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163 Cards in this Set
- Front
- Back
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Basic Water Facts
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Makes up about 60% of a persons body weight
Found in blood vessels, cells, tissues and organs Incompressible - molecules are not crowded |
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Water Functions in the Body
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Transport - brings nutrients to the cells
Cleansing agent - carries waste products away from cells Solvent for minerals, vitamins, amino acids, glucose Participates in many reactions Body temperature & sweat Lubricant for joints Protects spinal cord and fetus Keeps optimal pressure on the eye retina and lens |
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Water Balance
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The brain regulates water intake
The brain and kidneys regulate water excretion Keeps body water content constant |
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Dehydration
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Lack of water in the body
Signs: thirst, weakness, headache, exhaustion, delirium, |
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Water Intoxication
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Water content too high
Signs: headache, muscular weakness, lack of concentration, poor memory, loss of appetite |
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How Much Water Is Needed In One Day?
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DRI meets approx 80% of days need for wayer
Men: 3.7 litres Women: 2.7 litres The body produces water from the break down of energy yielding nutrients |
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Factors that increase water need
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Alcohol and caffeine
Hot weather, airplanes & sealed buildings Diabetes, kidney disease Dietary fibre, protein, salt, sugar Exercise High altitude Pregnancy and breast feeding Diarrhea, vomiting or fever Surgery, blood loss, burns, ketosis |
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Water Types
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Hard water - high calcium & magnesium
Soft water - high sodium Best Choice: Rich in calcium & magnesium, low in sodium |
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Bottled Water
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250 - 10 000 times the cost of tap water
33% contaminated with bacteria, arsenic or synthetic organic chemicals 25% of bottled water is drawn from the tap |
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Minerals
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Inorganic
Naturally occuring Homogeneous substances Chemical elements |
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Major minerals
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Essential mineral nutrients found in amounts larger then 5 grams in the human body
Calcium, phosphrous, potassium, sulfur, sodium, chloride, magnesium |
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Trace minerals
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Mineral nutrients found in amount less then 5 grams in the body
Iron, zinc, copper, iodine |
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Electrolytes
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Compounds that party dissociate in water to form ions such as K+ and Cl-
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Fluid and electrolyte imbalance
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Loss of water and minerals from cells, disrupted heartbeat
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Buffers
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Molecules that help keep pH of a solution by gathering or releasing H+ions
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Acid - base balance
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Excess H+ makes fluids acid - lower pH
Excess OH-makes fluids basic - raise pH |
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Calcium Functions
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Most abundant mineral in the body - 99% stored in the bones and teeth
Integral part of the bones , together with phosphorous Bones serve as a bank to release calcium Regulates transport of ions across cell membrane Nerve transmission Blood pressure Muscle contraction & heartbeat Secretion of hormones, digestive enzymes, neurotransmitters Blood clotting Activates cellular enzymes that regulate many processes |
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Hydroxyapatite
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Chief crystal in bone formation
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Calcium sources
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Dairy
Vegetables: rutabaga, broccoli, beets, turnips, mustard, bok choy, kale Small fishes with bones Almonds |
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How is blood calcium regulated?
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Calctonin and parathyroid hormone
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Calctonin
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Made in the thyroid gland
Acts to stop withdrawal of calcium from the bone o to slow the absorption from the intestine when the calcium concentration in the blood rises too high |
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Parathyroid Hormone
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Produced by the parathyroid glands
Acts opposite to calctonin |
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Excess calcium
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kidney stones - a collection of calcium in the kidneys
Interferes with mineral absorption Constipation |
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Calcium deficiency
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Osteoporosis
1 in 4 women & 1 in 8 men Bones are fragile, spine cant support weight, vertebrae crushing down pinch major nerves Could be due to estrogen or testosterone deficiency Excess protein Sodium caffience and soft drinks Inadequate vitamin K |
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Trabecular bone
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Calcium containing crystals inside the bone - part of the calcium bank
Provides strength along lines of stress Tapped to raise blood CA when days supply is short Sensitive to hormones |
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Cortical bone
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Dense, ivory like bone forming the exterior sturdy outer wall
Astronauts experience rapid bone loss |
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Calcium
2 - 12 13 - 30 31 - 50 51 + |
Grow strong bones
Achieve peak bone mass Maximize bone retention Minimize bone loss |
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Phosphorous
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2nd most abundant mineral in the body; ~ 85% combined with Calcium in the crystals of bone & teeth
Part of cell’s genetic material - DNA & RNA Essential for growth & renewal of cells Principal component of cell membranes - forms principal part of molecules of phospholipids Assists in energy transfer Assists many enzymes & vitamins in extracting energy from nutrients Plays a critical role in buffering systems May cause calcium excretion, calcification of kidneys |
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Phosphorous food sources
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animal protein; cottage cheese, salmon, milk, steak, navy beans
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Magnesium sources and recommendations
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~ 1 ounce in a 130-lb person
~ 50% in bones; rest in muscles, heart, liver, soft tissues ~1% in body fluids With low intake, bone supplies it to maintain constant blood level or kidneys conserve it RDA – 310 mg/d/F; 400 mg/d/M UL – 350 mg/d (synthetic - supplements or drugs) Good food sources – black beans, spinach, oysters, soy milk, black-eyed peas, yogurt |
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Magnesium functions, excess & deficiency
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Needed for release & use of energy; directly affects metabolism of K, calcium, vitamin D
Assists enzyme actions and in normal muscular contraction/relaxation -calcium promotes contraction, Magnesium relaxes muscles afterwards Assists in nerve transmission Holds calcium in enamel of teeth Deficiency Due to inadequate intake (easily washed & peeled away during processing), vomiting, diarrhea, alcoholism or protein malnutrition Symptoms: weakness, uncontrollable muscle spasms (fatal in heart), convulsions, hallucinations , appetite loss, confusion Excess Excess supplement or antacids; medications for kidney Diarrhea, dehydration, acid-base imbalance |
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Sodium functions
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• Together with chloride & potassium,
• Maintains cells’ normal fluid & electrolyte balance and acid-base balance • Essential to muscle contraction & nerve impulse transmission |
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Sodium intake
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• Adults Canadians 19-30 years - sodium consumption on average:
• Males 4000mg • Females 2800 mg • Increased fast food/processed food = increased intake • Asian peoples, whose staple sauces and flavorings are based on soy sauce and MSG • May consume the equivalent of 30 to 40 grams of salt per day |
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DASH
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Dietary Approaches to Stop Hypertension Diet
Increase potassium & reduce sodium by: • Greatly increasing intakes of F & V, fish, low-fat dairy foods • Eating adequate amounts of meats, whole grains, legumes • Eating small portions of red meat, butter, high-fat foods & sweets • Greatly reducing sodium & salt • Increase physical activity |
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DASH Diet
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When people consume the DASH diet with progressively lower sodium, their blood pressure falls
Diet is modified to provide abundant magnesium, potassium, and calcium, as well as adequate protein and fiber, the average blood pressure drops even lower at each level of sodium intake Weight loss is also common with this diet regime |
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Sodium Excess and Deficiency
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Deficiency:
• No known human diets lack sodium • Muscle cramps, mental apathy, loss of appetite Excess: • Hypertension, hypertension-related stroke (cerebral hemorrhage) • Cardiovascular disease • Salt-sensitive (any amount raises BP) – those with kidney disease, diabetes, high blood pressure; African descent, parents have high blood pressure; age over 50 • Excess sodium causes increased calcium excretion |
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Potassium functions, deficiency and excess
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• Principal positively charged ion inside body cells
• Good food sources – whole fresh foods; OJ, banana, lima beans, salmon, baked potato, avocado, honeydew melon Functions • Plays a major role in maintaining fluid & electrolyte balance & cell integrity • Critical to maintaining heartbeat • Facilitates making of proteins, nerve impulse transmission, contraction of muscles Deficiency • Dehydration leads to K loss inside cells; muscular weakness, hypertension, glucose tolerance impaired; metabolic acidity, Ca losses, kidney stones Excess • Muscular weakness, vomiting, stops heart if given thru a vein; overdose (by mouth) not fatal – excess K in stomach triggers a vomiting reflex to get rid of it |
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Chloride - everything
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Major negative ion in the body
Outside cells, accompanies sodium; inside cells, pairs with K In its elemental form, chlorine forms a deadly gas; if dissolved in fluid, used as a disinfectant Found in salt and processed foods Functions Special role as part of hydrochloric acid to maintain strong acidity in stomach for protein digestion The pH of HCL in stomach is 1.5 Bicarbonate is released into the small intestine from the pancreas to balance out the stomach acid Can act as a buffer to maintain acid-base balance, fluid & electrolyte balance Deficiency: If deficient – growth failure in children, muscle cramps, mental apathy, loss of appetite Excess: Harmless – a poison but evaporates in water... Vomiting |
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Sulphur - everything
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Not used by itself as a nutrient
Sulphate is oxidized form in food & water Present in thiamin & in proteins; high amounts in skin, hair, nails Good food sources – all protein-containing foods Functions Required for synthesis of sulphur-containing compounds; helps strands of protein assume their functional shapes (S-S bridges) Deficiency is unknown Excess Diarrhea which may cause damage to colon |
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Trace minerals
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• Essential mineral nutrients found in humans less than 5 g
• Past research mostly in animals; some have human recommendations; others considered essential in animals, but not for humans • Human recommendations for - iodine, iron, zinc, selenium, fluoride, chromium, copper, manganese, molybdenum • Essential for animals (human requirements under study) – arsenic, boron, nickel, silicon, vanadium • Essential for animals (no known human intake limitation) - cobalt |
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Iodine
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Body needs minute quantity, but critical for human nutrition
Functions Part of thyroxine, a thyroid hormone Helps regulate growth, development, basil metabolic rate Deficiency One of the world’s most common & preventable forms of mental retardation; Goiter is the enlargement of the thyroid gland – sluggish, gain weight; Cretinism is irreversible mental/physical retardation of an infant; reversible if detected within 6 months of pregnancy, if not child has 20 IQ Excess Goiter-like thyroid enlargement [toxic, can block airways, cause suffocation] Recommendations Good foods sources – iodized table salt; seafood’s, bakery products that contain dough conditioners, milk (iodine used in disinfecting milking equipment) Iodine in food varies – iodine in soil varies in most parts of the country; plentiful in oceans Potassium iodide – used as a medication for preventing thyroid cancer caused by exposure to radioactive iodine – a nuclear emergency |
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Iron functions
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Functions
• Every living cell contains iron; • Iron is in ~80% of blood • Part of hemoglobin in red blood cells – carries O2 from the lungs to the tissues • Part of myoglobin in muscles – carries & stores O2 for the muscles • Necessary for many enzymes in energy pathways to release energy • Needed to make new cells, AA, hormones, & neurotransmitters |
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Iron deficiency
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• Iron deficiency: depleted iron stores without being anemic; physical work capacity & productivity impaired; less physically fit
• Iron deficiency anemia (IDA): A severe depletion of iron stores resulting in low blood hemoglobin; red blood cells shrink & lose color o Symptoms – weakness, pallor, headaches, reduced resistance to infection, inability to pay attention, tendency to feel cold, tiredness, apathy • Pica: abnormal appetite for ice, clay, paste, soil, & other non-nutritious substances, common in pregnancy • Deficiency usually caused by malnutrition; could be due to blood loss, heavy menstrual periods, parasitic infections, ulcers & other sores, inflammation of the GIT; o In developed countries, could be due to over-consuming foods rich in sugar & fats and poor in nutrients |
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Iron excess
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Difficult to excrete from the body
Iron overdose from supplements – # 1 cause of fatal accidental poisoning among young children Hemochromatosis: caused by a hereditary defect where intestine absorb excess iron at a high rate despite excess build up in cells Results in fatigue, infections because bacteria love iron-rich blood, mental depression, abdominal pains, liver failure, abnormal heartbeats, etc. Possible increased risk of heart disease, colon cancer Free iron is a powerful oxidant, starts free-radical reactions Growth retardation in children, acidosis, bloody stools, shock |
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Iron Recommendations
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Good food sources – clams, beef liver, beef steak, enriched cereal, Swiss chard, spinach, black beans, navy beans
Normally 10-15% absorbed; absorption often increases with low intake or special need Heme iron – from meat, fish & poultry, more reliably absorbed Non-heme iron – from plant sources; less absorbed Enhancers - vitamin C, MFP factor Inhibitors - phytates (legumes, whole grain cereal), tannins (coffee, tea), calcium & phosphorous (milk) Iron supplements – medical protocol for pregnancy and vegetarians/vegans often need |
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Iron in food
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Absorbing Iron
MFP factor: found in meat, fish and poultry Promotes the absorption of non-heme iron from other foods eaten at the same time Vitamin C can triple absorption of non-heme iron from foods eaten in the same meal The amount of iron absorbed from a meal depends partly on the interaction between promoters and inhibitors of iron absorption Cooking in an iron pan adds iron to food This iron is in the form of iron salts somewhat like those in supplements The iron content of 100 grams of spaghetti sauce Simmered in a glass dish = 3mg Cooked in a black iron skillet = 87mg |
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Zinc Functions
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Occurs in very small quantities
Zinc and iron share the same absorption site Assists many (~ 100) enzymes used to metabolize carbohydrates, protein and fat Helps regulate gene expression in protein synthesis Heme in hemoglobin Assists in immune reactions, liberates & transports vitamin A from storage in the liver (production of active form in visual pigments) Essential to taste perception, wound healing, sperm production, fetal development, growth & development in children Involved in disposal of damaging free radicals Affects behavior & learning |
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Zinc Recommendations and Deficiency
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Recommendations
Good food sources include oysters, shrimps, beef steak, yogurt, enriched cereal, pork chop, leavened (with yeast) bread Deficiency Population groups at risk for deficiency: pregnant women, young children, elderly, poor Growth failure in children (thyroid function disturbed & slows energy metabolism); abnormal vision Skin lesions, delayed sexual maturation, diarrhea Abnormal taste, loss of appetite, poor wound healing, vitamin deficiencies |
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Zinc Excess
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• Blocks copper absorption which leads to degeneration of heart muscles in animals
• May reduce HDL concentration • Inhibits iron absorption from GIT due to competition with protein carrier; likewise, too much iron inhibits zinc absorption • Loss of appetite, impaired immunity • Excess zinc (from supplements like cold lozenges & sprays) excreted out |
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Selenium Everything
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Assists enzymes that work to prevent formation of free radicals
Works with vitamin E as an antioxidant Plays a role in activating thyroid hormone (BMR regulation) Recommendations Good food sources include meats & shellfish, grains & veggies grown on selenium-rich soils Deficiency Uncommon if balanced diet of mostly unprocessed foods Soils vary in content Muscle degeneration & pain Cataracts Depressed sperm production, prostate cancer Fragile red blood cells, pancreatic damage Growth failure in children Heart damage Excess Possibly from supplements which may raise risk of skin cancer Diarrhea, hair loss, nerve abnormalities |
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Fluoride Everything
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• Not essential to life, but beneficial to public dental health
• Has an ability to inhibit dental caries • Functions – help form bones & teeth (more decay resistant fluorapatite); acts directly on bacteria of plaque, suppressing metabolism & reducing acid produced • Good food sources – drinking water from the tap with fluoride, tea, seafood Deficiency • Susceptibility to tooth decay Excess • Fluorosis – irreversible discoloration of teeth due to wider availability of fluoride-containing products such toothpaste, mouthwash & supplements or excess fluoride in tap water • Mottled teeth enamel – not a health problem; more of a cosmetic problem • Fluoridation – 1 ppm - as a public health measure to prevent population-wide tooth decay; some water supply may contain too much fluoride (2-8 ppm) |
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Chromium everything
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Biologically-active chromium or glucose tolerance factor – chromium exists in food in complexes with other compounds
Good food sources include liver, unrefined whole grains, nuts, chesses, vegetable oils; easily lost during processing Functions Works with insulin to regulate & release energy from glucose “Glucose tolerance factor” No ability to promote weight loss/muscle gain Does not lower blood cholesterol Deficiency Abnormal glucose metabolism Diabetes-like high blood glucose – (slim person with diabetes like blood glucose) Excess Supplements may cause skin eruptions Other forms may cause cancer & other abnormalities |
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Copper Everything
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• RDA – 900 ug/d (F/M); UL – 10,000 ug/d
• Good food sources include organ meats, seafood, nuts & seeds, drinking water (copper plumbing pipes) Functions • Helps form hemoglobin & collagen • Part of several enzymes (oxygen handling ability) to release energy • Plays role in handling of iron and energy release & controlling free radical activity in tissues Deficiency • Rare • Severely disturbs growth & metabolism in children Can impair immunity & blood flow through arteries in adults Excess • Supplements can cause it; vomiting, diarrhea, liver damage |
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Other trace minerals
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• Molybdenum (DRI set) – part of several metal-containing enzymes (some are giant proteins)
• Manganese (DRI set) – works with dozens of different enzymes that facilitate body processes • Boron – influences activity of many enzymes; low intake increases susceptibility to osteoporosis • Cobalt – part of vit B12 (alternate name for B12:cobalamin) • Nickel – important for health of many body tissues • Silicon – involved in bone calcification in many animals • Barium, cadmium, lithium, etc. |
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Relationship between trace minerals
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• An overdose of any trace mineral could have a large negative effect on the body
• Research shows a lot of interaction between trace minerals • Slight Mn overdose can aggravate an iron deficiency |
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BMI
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divide weight in kg by height in meter2
o Obese BMI 30+; o Overweight 25.0 – 29.9 o Normal 18.5 – 24.9 o Underweight <18.5 |
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Risks from being underweight
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• Thin/underweight individuals
o Die first during a siege or famine o Disadvantaged during times of surgery or illnesses that limit their intakes (fasting for tests, low appetite) or increase their outputs (vomiting/diarrhea) • Those fighting a wasting disease o Cancer may die from starvation • People need body fat stores for energy reserves, protection for the bones & organs, nutrient stores, body temperature controls |
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Risks from being overweight
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• Mild to moderate overweight
o Increased risks for diseases o Risk of premature death • Obese o Now declared a chronic disease o Major risk for cardiovascular disease • High blood pressure, heart disease • Other risks o High blood lipids, sleep apnea, gout, arthritis o Abdominal hernias, liver malfunction, flat feet o Varicose veins, gallbladder disease o Respiratory problems, kidney stones o Complications in pregnancy, surgery o High accident rate, some cancers |
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Abdominal fat
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• Who is most prone to abdominal fat?
o Women after menopause, men, people with diets high in saturated fat • What are the risks of extra abdominal fat? o Increased diabetes, pressure on organs, high risk of coronary heart disease, cancer • What is an “apple” shape and what is a “pear” shape? o Pear = bigger bum and thighs |
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Visceral fat
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• Increased risks for diabetes, stroke, hypertension, coronary artery disease
• Central fat released readily into the blood stream • Significant contribution to the blood’s daily burden of LDL |
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Energy references for man and woman
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o Reference woman – ‘active’ physical activity, 21.5 BMI, 140 cm tall, weigh 57 kg (126 lb)
o Reference man – ‘active’ physical activity, 22.5 BMI, 154 cm tall, weigh 70 kg (154 lb) |
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The thermic effect of food
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• Diet-induced thermogenesis (DIT)
• Stepped-up metabolism in the 5 hour or so after a meal • Effects are minimal • TEF is greater with spicy foods • The body uses a little it more energy to digest cold foods than hot |
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Estimating energy requirements
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• Gender – women generally have less LBM than men
• Age – BMR declines an average of 5% per decade • Physical activity – grouped according to intensity (very active, active, low active, sedentary) • Body size & weight – taller & heavier people have higher BMR – WHY? • Quick & easy way: o Men – kg BW x 24 = calories/day o Women – kg BW x 22 = calories/day |
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BMI not suited for
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o Athletes because highly developed muscles increase values
o Pregnant & lactating women because increased weight is normal in childbearing o Adults over 65 years because people ‘grow shorter’ with age |
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Anthropometry
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Direct body measurements
o Skinfold or fat-fold test (calipers) – accurate estimate of total body fat & fair assessment of location o Waist circumference (tape measure) – visceral fatness; cut-off points: men 102 cm (40 in); women 88 cm (35 in) o Consistency is a concern with these techniques |
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Density
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Lean tissue is denser than fat
o Underwater weighing – measures body weight compared with volume displaced; lean tissue denser than fat tissue o Air displacement plethysmography – Bod Pod measures air displacement by the body; estimates & tracks body composition over time o Expensive! |
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Conductivity
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o Bioelectrical impedance analysis– lean tissue & water conduct electrical current; fat does not
o Need adequate water in body for accurate results |
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Average body composition
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• Men:
o 45% muscle, 25% organs, 15% fat, 15% bone • Women: o 36% muscle, 24% organs, 27% fat, 13% bone o Substantially greater fat tissue is normal & necessary for reproduction |
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Go signals
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• Hunger – physiological need to eat; triggered by contracting empty stomach & small intestine, the hormone grehlin, and chemical/nervous signals in brain
o Hunger response adapts quickly to changes in food intake – stomach contracts or enlarges • Appetite – physiological desire to eat; learned motivation, positive sensations; affected by aversions, cravings, environment, temperature o Endorphins – brain’s pleasure molecules; enhance desire for the taste of delicious foods; triggered by smell, sight, taste of foods o Inborn preferences for fatty, salty & sweet tastes o Affected by social interactions, some diseases, drugs (depressants) |
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Stop signals
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Satiation
• Perception of fullness & satisfaction that halts eating; determines how much food is consumed at one sitting • Stomach distention: The stomach stretches which signals the brain of fullness • Nutrients in the small intestine, hormonal & neural signals inform the brain’s hypothalamus about the meal • Affected by type of food, stress, activity level Satiety • Fullness lingers hours after a meal; determines length of time between meals • Wait 20 minutes after eating to know if satisfied or not |
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Stop signals II
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Hormone “Leptin”
• A peptide hormone produced by the fat tissue; suppresses appetite & food intake between meals; • Has other regulatory roles Protein • Perhaps the most satiating food together with fiber; Sustains satiety far longer than those high in fat, white flour, or sugar • Protein is satisfying but does not provide a lot of energy |
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Enzyme Theory of Obesity
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• Elevated lipoprotein lipase (LPL) enables fat cells to store triglycerides
• Fat cells of obese people contain more LPL (than lean) |
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Fat Cell Number Theory of Obesity
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• Number and size of fat cells determine body fatness
• Fat cell numbers increase in growing years • Fat cells do not grow or reduce in number – they will either grow in size of decrease in size • Fat cell number may increase more rapidly in obese children (than lean) |
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Set Point Theory of Obesity
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• Body ‘chooses’ a weight & defends it by regulating behaviors & metabolic activities
• When weight is lost or gained, set-point changes metabolic energy expenditure to restore ‘chosen’ weight |
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Thermogenesis Obesity Theory
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• Enzymes ‘waste’ small % of energy as heat, thus body can spend more excess energy (rather than store more)
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Genetics and Obesity
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• Genetics strongly influences a person’s tendency to become obese
• One obese parent: 40-70% risk of child being obese • Adopted children are similar in weight to their biological parents – pushes the genetic side of obesity • Identical twins weigh the same (not fraternal twins) when reared in same environment; if they are not in the same environment, they weigh differently – pushes the nurture side of obesity • Lifestyle choices determine whether the genetic tendency is realized • We are genetically predisposed to a certain weight but the surroundings will effect heavily |
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External Cues to Over Eating
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• Eating behavior in response to exposure, yearning, craving, addiction, stress, depression, compulsion, loneliness,
o Comfort in food o Addiction to the endorphin release in the brain • High body fatness - a diet ‘cafeteria –style’ with a variety of sweets, snacks, condiments & main dishes • Lower body fatness - a diet with a wide variety of veggies, grains, low fat proteins, and not many treats |
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Change in Body Weight
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• Reflects shifts in body fluid content, in bone minerals, in lean tissues (muscles), in contents of bladder or digestive tract
• Correlates with time of day; We weigh the least before breakfast • Quick large changes usually due to large changes in body fluids; dramatic but temporary change with little change in the long run • 3500 calories are in one pound of fat |
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Diuretics and Laxatives
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o Diuretics causes an individual to release more fluid
o Laxatives cause food to move through the body very quickly. Little minerals and vitamins. The body will eventually adapt. The smooth muscle in the large bowel will stop to function. |
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Diet Pills
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o Designed to speed up metabolism
o Can result in cardiac arrest |
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Sweating
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o Dehydrating in order to make weight
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Smoking
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o An appetite suppressant
o When a person quits smoking they may try to replace the “hand to mouth” concept o In 20% in the female population, there is a gene that is expressed that results in weight gain. The gene is turned on once smoking occurs. |
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Low Carb Diets
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• Skipping meals
o Get very hungry and then over eat at the next meal • Over exercising o Same result as skipping meals |
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Response to Early Food Deprivation
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• In fasting, glycogen from liver depleted quickly and then glycogen from muscles not released
• Fuel for muscles, heart, other organs = FAT • Fuel for Nervous system = GLUCOSE • Body fat cannot be converted to glucose • Body protein can be converted to glucose; proteins are sacrificed to supply raw materials to make glucose |
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Fasting for 10 Days
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• The body will start to use up stores
o Death would ensue with continued consumption of lean tissue; blood proteins, liver, heart muscle, lung tissue burned as fuel • Fasting or starving people remain alive only until their stores of fat are gone or until half their lean tissue is gone, whichever comes first |
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Ketone Bodies
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• Produced for the nervous system to spare tissue protein to feed the brain and nervous system when too little carbohydrate is available
• Made from partially broken down fragments & some AA • Ketosis – may harm the body; upsets the acid-base balance of the blood; promotes excessive mineral losses in the urine • Leads to tendency to overeat/binge with food |
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Carbohydrate Restriction
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• Loss of appetite accompanies any low-calorie diet
• Sizable initial weight loss due to ketosis; as carbohydrates run out, body breaks down fat & protein for energy & form ketone bodies to feed the brain & nervous system • Severe calorie restriction means loss of water, glycogen, & lean tissue • High intakes of cholesterol, fat, saturated fatty acids lead to high cholesterol • No milk or fruits & minimal veggies result in lack of needed nutrients & phytochemicals • Lack of fiber may lead to GIT problems such as colon cancer, kidney disease, heart disease or constipation |
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Weight Gain
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Excess carbohydrates
• First stored as glycogen to be used to energy • When glycogen stores are full, excess carbohydrates are converted to fat and stored as fat Excess Fat • Efficiently & easily stored as body fat Excess Protein • Only stored in the body in response to exercise; present as a working tissue; excess amino acids have their nitrogen removed & are used for energy or converted to glucose or fat • Too little Physical Activity encourages body fat accumulation • Overall, weight gain comes from spending less energy than is taken in |
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Weight Gain and Alcohol
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• Alcohol has calories that are used for fuel or converted into body fat for storage
• 7 calories per gram • Alcohol slows down the body’s use of fat for fuel by as much as ≈ 33%, causing more fat to be stored Primarily stored as visceral fat |
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Ideal Weight Loss Diet
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• Reduce calorie intake by:
o 500 to 1000 calories/day for BMI >35 o 300 to 500 calories/day for BMI 27 – 35 • Best diet for managing weight: o Abundant fresh fruits and vegetables o Low-fat milk products/lean meat, fish and poultry o Whole grains and legumes for fibre o Moderate carbohydrates, adequate protein & fiber, low SAFA/Trans fat |
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High Protein Low Carb Diets
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• Laboratory studies have shown that when energy intake is the same, there is no difference in weight loss on a high-protein, low-carbohydrate diet compared to a lower-protein, higher-carbohydrate diet
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Energy Density
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• A measure of the energy provided by a food relative to its weight
• To lower caloric intake, reduce the energy density of the diet • Energy in must be less than energy expended • Calorie intake must decrease to attain weight loss • Diet based on all the food groups may be the safest and easiest in the long term • While providing adequate essential nutrients and limiting saturated and trans fat intake • Increase physical activity |
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PA for Gaining Weight
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• Choose strength building exercise combined with a high-calorie diet
• Use a balanced exercise routine to gain muscle & fat • Perform exercise with increasing intensity • Choose nutritious foods with high energy density • Increase portion sizes, eat frequently • Avoid tobacco – depresses appetite, kills taste buds & sense of smell |
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Drugs and Surgery to Treat Obesity
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Prescription Drugs
• Suppress appetites; inhibit pancreatic lipase activity Over-the-Counter Drugs & Products • Reduce taste sensations & appetite Surgery • Reduces stomach size; delays passage of food from stomach to intestine; liposuction or lipectomy to remove external body fat • Traditional stomach size is about 1 -2 cups Herbal products • Effectiveness & safety not proven, herbal teas, Ephedra, dieter’s teas • For many, their effectiveness and safety have not been proved • “Natural” does not always mean safe o Belladonna, hemlock, and sassafras all contain toxins • Check the Office of Natural Health Products web site • To identify status of herbs or natural products of which there are claims relating to weight loss |
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Training
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• Regular practice of an activity; leads to physical adaptations of the body; improve flexibility, strength, & endurance
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Physical Activity
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• Bodily movement with muscle contractions, substantially increasing energy expenditure
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Exercise
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• Planned, structured, vigorous, repetitive bodily movement that promotes or maintains physical fitness
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Canadian Goal by 2015
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– Healthy Eating
• Increase by 20% Canadians who make healthy food choices – Physical Activity • Increase by 20% Canadians who participate in regular physical activity – 30 min/day moderately vigorous – Healthy Weights • Increase by 20% Canadians at a “normal” or healthy BMI |
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Benefits of Being Physically Fit
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More Restful Sleep
• So body can repair muscles, build new tissues • This can vary with time of work-out Better Nutritional Health • Often people want to make healthy choices to ensure best outcomes from physical activity • Sometime people increase their caloric intake too much- why? Improved Body Composition • Less body fat, more lean mass Improved Bone Density • Weight-bearing physical activity builds bone strength Enhanced Immunity • To colds & other infectious diseases Lower Risks • Of some types of cancers: colon, breast Increased Blood Circulation & Lung Function • Increased oxygen intake and CO2 output; exercises heart and lungs |
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Benefits of Being Physically Fit II
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Lower Risks of CVD
• Lowers blood pressure & cholesterol, raises HDL-Cholesterol, reduces intra-abdominal (visceral) fat stores Lower Risk of Type 2 Diabetes • Normalize glucose tolerance Reduced Risk of Gallbladder Disease • (In women) • Lower levels of blood lipids Lower Incidence & Severity of Anxiety & Depression • Improves mood; endorphin release; feeling of self efficacy Stronger Self-Image • Sense of achievement; feeling of self efficacy Increased Length and Quality of Life Social outlet OR Time for self |
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Canada's PA Guide to Healthy Active Living
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Choose a variety of activities from these three groups:
• Endurance: 4-7 days/week – Continuous activities for your heart, lungs, & circulatory system • Flexibility: 4-7 days/week – Gentle reaching, bending, & stretching activities to keep your muscles relaxed & joints mobile • Strength: 2-4 days/week – Activities against resistance to strengthen muscles & bones & improve posture • Recommended: 60 min moderately intense activity (walking, jogging); 30 min not always enough to maintain healthy BMI |
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Essentials of Fitness
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• Flexibility – capacity of joints to move through a full range of motion; ability to bend & recover without injury (stretching)
• Muscle strength – ability of muscles to work against resistance (weight training) • Muscle endurance – ability of a muscle to contract repeatedly within a given time without becoming exhausted • Cardiorespiratory endurance –ability to perform large muscle dynamic exercise (aerobics) |
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PA Pyramid
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• Do sparingly – limit sedentary activities; watch TV, video, or movies; play computer games
• 2-3 days/week – engage in strength & flexibility activities; sit-ups, push-ups; weight lifting; stretching exercises (yoga); leisure activities (dancing, bowling) • 3-5 days/week – engage in vigorous activities regularly; aerobic activities (kickboxing, power walking, biking, swimming, rowing) • Everyday – be as active as possible; walk or bike to class, work, or shops; play with children |
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How Muscles Become Fit
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• Muscle cells & tissues - respond to physical by gaining strength & size (hypertrophy); opposite is atrophy
• Note: increased dietary protein does not guarantee increased muscle mass |
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Weight Training
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• Use of free weights or weight machines;
• Resistance training such as boxfit classes or yoga/pilates; • Method to build LBM, develop & maintain muscle strength & endurance • Benefits: – Improved posture; – Reduced risk of back injury, mobility decline, and osteoporosis – Enhance performance in other sports • Football, Hockey, Golf, Cycling, etc. |
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Cardio Training
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• Enhances the ability of the heart & lungs to deliver oxygen to the muscles
o Increased cardiac output (blood volume discharged) and oxygen delivery o Increased heart strength & stroke volume (amount ejected from the heart) o Slowed resting pulse; improved circulation o Increased breathing efficiency; raised HDL o Improved circulation; reduced BP • Examples: swimming, brisk walking, jogging, soccer, hockey, basketball, rugby |
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The Body's Active Use of Fuel
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• Carbohydrates – glucose (esp. stored glucose of muscle glycogen)
• Fats – fatty acids (prolonged aerobic exercise) • Proteins – spared with enough glucose from CHO; little use for energy – more for repair/building muscle tissue) • Body uses different mixtures of fuels depending on intensity & duration of its activities & depending on its own prior training (aerobic vs. anaerobic) • Each of these nutrients play a role in exercise & excluding any one of these in the diet can affect health & performance |
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Anaerobic Use of Glucose
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• Intense activity (weight lifting) uses glycogen quickly; muscles break down glycogen supply by anaerobic mechanism
• Lactic acid – produced in anaerobic activity; in excess, travels to liver & converted back to glucose • When lactic acid accumulates, it is hard to move muscles |
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Aerobic Use of Glucose
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• Moderate physical activity (easy jogging or walking) uses glycogen slowly
• Muscles extract their energy from glucose & fatty acids (conserves glycogen stores) |
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Factors Affecting Glucose During PA
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• Intensity & duration of activity
o First 10 min, muscles use their glycogen stores o Within first 20 min, muscles increase uptake of blood glucose o Longer than 20 min, body uses less glucose & more fat for fuel o Glycogen depletion occurs after 2 hr vigorous exercise • Depends on… • Degree of training o Muscles that deplete glycogen through work adapt to store greater amounts o Trained muscles burn more fat at higher intensities for longer periods o Diabetic patients – their muscles adapt to PA and may reduce need for daily drug doses & help body lose fat |
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Maintaining Glucose for Activity - Endurance Athletes
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• Eat a high carbohydrate diet regularly
• Take glucose (usually in carbohydrate containing sports drinks or gels) periodically during endurance activities • Eat simple carbohydrate-rich foods ASAP after performance/training to replenish glycogen storage – Example: • Train the muscles to maximize glycogen stores (carbohydrate loading – 6/7 day plan) |
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Carbohydrate Loading
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• Muscles trained to store extra glycogen temporarily before competition
• Can nearly double muscle glycogen concentration • Athlete tapers training during the week before competition, then eats a high-carbohydrate diet (10 g/kg BW) during the 3 days prior to the event • Extra glycogen needed for activities 90 min or longer; helps meet fluid needs, water released when glycogen is broken down • Eating high-carbohydrate foods or drinking high-carbohydrate energy drinks after physical activity enlarges glycogen stores • Appropriate Activities: – Marathons, long-distance swimming, cross-country skiing, long bike races – Triathlons, 30-K runs, cycling time trials – Long-distance canoe racing • Inappropriate Activities: – Football games; 10-K runs, walking & hiking – Most swimming events, weight lifting – Basketball games, most track & field events |
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Fat and PA
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TOO MUCH IS NOT GOOD…
• Consuming high-fat, low-carbohydrate diets impairs performance; small glycogen stores are quickly depleted • High-fat diets carry risks of heart disease; adverse health effects from prolonged high-fat diets make them an unwise choice for athletes TOO LITTLE IS NOT GOOD… • Overly restricting fat below 20% of total energy – failure to consume adequate energy & nutrients; very-low fat diets inhibit performance • Endurance athletes - recommended to consume 20-30% of E from fat • Body fat – theoretically an unlimited source of energy; fat cells release FA all muscles share |
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Factors Affecting Fat Use in Physical Activity - Intensity
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Intensity & Duration of Activity
• Fat broken down for energy only by aerobic metabolism after 20 min of sustained submaximal activity; they empty out their fat stores & shrink in size • Glucose starts to be burned in aerobic activity for first 15-20 minutes and when ability to provide energy aerobically is surpassed >80% max. HR Over 60 minutes of aerobic activity |
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Factors Affecting Fat Use in Physical Activity
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Degree of Training
• Training (repeated aerobic activity) stimulates the muscles to develop more fat-burning enzymes • Aerobically trained muscles burn fat more readily than untrained muscles; increase in BMR after physical activity • Heart & lungs stronger & better able to deliver oxygen to muscles; therefore becomes easier over time |
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Protein and PA
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• Protein for building muscle tissue
o Eating protein, together with CHO, after PA enhances muscle protein synthesis by providing needed AA o Both protein dismantling & protein-synthesizing equipment of individual muscle cells work together to remodel muscles • Protein for fuel o Athletes use a little more protein as fuel o Proteins contribute about 10% of total fuel used • Diet affects protein use during activity o A CHO-rich diet spares protein from being used as fuel o Some AA can be converted into glucose when needed |
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Using Protein and AA
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• Dietary protein provides the needed amino acids for the synthesis of new muscle protein
o However, the true director of synthesis of muscle protein is physical activity o Repeated activity signals the muscle cells’ genetic material to begin producing more of the proteins needed to perform the work at hand |
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Factors Affecting Protein Use in Physical Activity
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Intensity & Duration
• Endurance athletes may become more dependent on body protein for energy (glycogen stores easily depleted) • Anaerobic strength training does not use more protein for energy, but does demand more protein to build muscle Degree of Training • In strength training (bodybuilders), the higher the degree of training, the less protein a person uses during activity at a given intensity |
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Athletes and Protein Consumption
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• Most athletes need somewhat more protein than sedentary people do
• Who needs more dietary protein? – Endurance athlete or body builder? • Recommended intake for power (strength or speed) athletes: 1.6 – 1.7 g/kg BW/d • Recommended intake for endurance athletes: 1.2 – 1.6 g/kg BW/d • No need for special foods, protein shakes, or supplements if you eat a balanced high-carbohydrate diet that provides enough total energy – Exceptions… |
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Nutrient Supplements and Athletic Performance
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• Use of vitamin-mineral supplements
• Elite athletes>university or college >high school; women athletes>men; athletes>general population • Nutrient supplements – do NOT enhance performance of well-nourished or active people; meeting energy needs usually means meeting V-M needs • Deficiencies of V-M do impede performance; V-M taken right before event does not improve performance. • Practice of “making weight”/on-going dietary restriction and/or intense training – single daily dose of V-M may be beneficial • Many vitamins and minerals assist in releasing energy from fuels and transporting oxygen |
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Vitamin E
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• Potent fat-soluble antioxidant
• Prolonged high-intensity physical activity produces damaging free radicals; needed to defend cell membranes against oxidative damage; little evidence that supplements can improve performance |
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Iron
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• Iron losses in sweat may contribute to deficiency; small blood losses through GIT; damages red blood cells in runners
• Muscles’ have high demand for iron to make iron-containing molecules of aerobic metabolism; • Supplement may assist if…habitual low intakes of iron-rich foods, high iron losses through menstruation, vegetarianism |
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Iron Deficiency
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• Impairs performance because iron helps deliver oxygen to muscles; insufficient oxygen reduces aerobic work
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Sports Anemia
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• Not a true IDA; an adaptive temporary response to endurance training; goes away by itself
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Sodium-Hyponatremia
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• Decreased concentration of Na in the blood
• Symptoms – debilitating cramps, confusion, seizure, severe headache, vomiting, bloating & puffiness (water retention) |
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Hydration and PA
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• Temperature regulation: sweat and water intake cool the body
• Heat stroke: Dangerous accumulation of body heat with accompanying loss of body fluid o Symptoms: clumsiness, confusion, loss of consciousness, dizziness, headache, nausea, stumbling,. hot./dry skin o Prevention: drink enough fluids before or during activity; rest in the shade when tired; wear lightweight clothing that encourages evaporation • Hypothermia: Loss of body heat; below-normal body temp – Symptoms: initially shivering, euphoria; then shivering stops, weakness, disorientation, apathy |
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Fluid Needs During PA
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• Athletes must hydrate before, during & after activity to replace all lost fluid
• During activity, thirst becomes detectable only after fluid stores are depleted • Schedule of hydration: – 2 hr before activity 2 to 3 c – 15 min before activity 1 to 2 c – Every 15 min during activity 1 to 1 ½ c – After activity 2 to 3 c for each pound BW lost • Weigh yourself before & after activity – difference is all water: 2 cups (500 mL) = 0.5 kg – why might this not work? |
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Types of Fluids
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Water
• Best drink for most active bodies; water rapidly leaves the GIT to enter tissues; cools the body from inside out Vitamin/Protein Water • Provides hydration with other micro/macronutrient Sports drinks • Replace glucose, fluid & electrolytes lost (Na, K, Cl in sweat, esp. in endurance athletes); • Warranted for those who do not want limit fat burn; those exercising more than 1 hour; in hot weather • Can provide a psychological edge for some Other beverages • Iced tea, carbonated beverages, alcohol are not good choices |
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Choosing a Diet for an Athlete
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• Nutrient density – nutrient-dense foods that supply maximum V-M
• Balance – High-carbohydrate (60-70% of total calories), • Glucose polymers (liquid supplements for CHO & energy) needed for heavy training & top performance – Moderate in fat (20-30%), – Adequate in protein (10-20%) • Protein - moderate in meats & milk products, extra servings of legumes, grains, veggies • Pregame meal – CHO-rich, light meal (300 – 800 calories), easy to digest (no hard bran/beans/fresh veggies), contain fluids (water or fruit juices); eat meal 3 – 4 hour before competition |
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Creatine
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Creatine supplementation may enhance performance of high-intensity strength activity such as weight lifting or repeated sprinting
Other studies have found no effect of creatine supplements on strength performance Appropriate long-term studies are lacking to determine safety Immediate side effects such as cramping and gastrointestinal distress May pose risk to athletes with kidney disease or other conditions Children as young as 9 years old are taking it with unknown consequences |
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Infectious Diseases
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• Caused by bacteria, viruses, parasites;
• Can be transmitted from one person to another through air, water, or food, by contact, or through vectors such as mosquitoes or fleas |
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Degenerative Diseases
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• Chronic, irreversible diseases
• Characterized by degeneration of body organs due to poor lifestyle choices o Poor food choices, smoking, alcohol use, & lack of physical activity o Lifestyle diseases, chronic diseases, or diseases of old age • Cancer, obesity |
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Bioterrorism
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Intentional spreading of disease-causing organisms or agricultural pests as a political weapon to produce fear & intimidate people
• Often shown on shows such as “24” • Rapid global spread of new & old diseases – H1N1 (swine flu) virus, SARS (sudden acute respiratory system), or resurrected TB, measles |
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Leading Causes of Death in Canada
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Cardiovascular Disease
• Heart disease, stroke & Cancer • Leading causes of death (2004) • Diet as a risk factor Degenerative Diseases • Genetic predisposition & personal medical history • Both uncontrollable & lifestyle choices Other causes of death • Chronic respiratory diseases, accidents |
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Nutrition and Immunity
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• Deficient intakes of many vitamin & mineral associated with impaired disease resistance
• Immune tissues first to be impaired in nutrient deficiency or excess • Some deficiencies are more immediately harmful to immunity than others • Malnutrition worsens disease, disease worsens malnutrition o Disease impairs food assimilation; drugs impair nutrition status • People-at-risk: those who restrict their intakes, very young or old, poor, hospitalized, or malnourished • A well-balanced diet is cornerstone in building the best possible immune system defense |
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Malnutrition and the Immune System
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• Skin – thinned, with less connective tissue
• Mucous membranes – microvilli flattened • GI tract – atrophy of intestinal cells • Lymph tissues – thymus gland, lymph nodes, & spleen reduced in size; T-cell areas depleted of lymphocytes • Phagocytosis – kill time delayed • Cell-mediated immunity – circulating T-cells reduced |
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Nutrition and Immunity
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Immunonutrition
• Influence of nutrients on the functioning of the immune system, esp. in medical nutrition therapies Deficiency or Toxicity • Either of a single nutrient can seriously weaken a person’s immune defenses, • Vitamin A deficiency Deficiencies • Known to impair immunity • Protein, energy, vitamin A, D, E, C, B, folate, copper, Mg, Se, Fe, Zn Toxicities • Known to impair immunity • Fe, Zn |
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Life Style and Risk Choices
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Risk Factors
• Known to be related to diseases but not proved to be causal • Presence of risk factors often predicts the occurrence of diseases Environmental, Behavioral, Social, & Genetic Factors • Tend to occur in clusters & interact with each other • Environmental: Living in the city • Behavioral: Handicapped person cant exercise (not in control) or choosing to eat fast food (control) High SAFA/Trans intake • Risk factor for cancer, high blood pressure, type 2 diabetes, atherosclerosis, obesity, stroke, diverticulosis • In many cases, one disease or condition intensifies the risk of another; e.g., diabetes leads to atherosclerosis & HBP • Family history & lab test results together = powerful predictors of diseases |
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Risks for CVD - Modifiable and Non-Modifiable
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Non-modifiable risk factors
• Age, gender & genetics • Increasing age: men 45+ years old; women’s risk increases 2-3x after age 55 or past menopause • Male gender: more cases in men than women; differences reduced after menopause; more women killed by cardiovascular disease • Genetics: siblings or parents history; more members or earlier age of onset = greater risk • Atherogenic diet: high in saturated fatty acid, Trans, cholesterol, sodium & alcohol Modifiable • Central obesity & physical inactivity • High blood LDL-C & low blood HDL-C • Hypertension • Diabetes |
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Metabolic Syndrome
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• Central obesity - visceral stores
• High fasting blood glucose or insulin resistance • Low HDL-C due to lack of exercise • Hypertension - high blood pressure • Elevated blood triglycerides - often high sugar diet • Poor waist-hip circumference ratio • Cigarette smoking o Damages the heart directly with toxins; raises blood pressure; damages platelets which makes clots more likely |
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Atherosclerosis
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The most common form of cardiovascular disease
• Characterized as plaques formed along the inner wall of the arteries – especially at branching points How it Develops • Diet high in saturated fatty acids: major contributor to the development of plaques & progression of atherosclerosis • Plaques – mounds of lipid material mixed with smooth muscle cells & cancer that develop in artery walls; formation of plaques initiates a complex inflammatory response to tissue damage • Arterial damage – due to high LDL-C, HBP, cigarette toxins, elevated H-cys, viral or bacterial infections |
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Aneurysm
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• Ballooning out of weakened artery wall
• Can burst & lead to massive bleeding/death |
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Thrombus
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• Stationary blood clot; could shut off blood supply to surrounding tissue
Coronary thrombosis: • Closes off a vessel that supplies heart muscle • Heart attack Cerebral thrombosis • Closes off vessel that feeds brain • Stroke |
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Embolus
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Thrombus that breaks loose & travel through the blood vessels until it reaches an artery too small to allow its passage
Embolism • Embolus that causes sudden closure of a blood vessel |
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Heart Attack and Stroke
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Heart Attack
• AKA Myocardial infarction • An embolism, thrombus with resulting tissue death, closes off Artery of the heart Stroke • Sudden shutting off of blood flow to brain by thrombus, embolism, or the bursting of a blood vessel |
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CVD, HBP & Atherosclerosis
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• Hypertension & atherosclerosis worsen cardiovascular disease, & each worsens the other
• Hypertension worsens atherosclerosis – stiffened artery strained by blood surges & high internal pressure; more plaques grow, more weakened vessels likely to burst & bleed • Atherosclerosis worsens hypertension – hardened arteries cannot expand to allow blood through freely through the body (esp. kidneys); kidneys sense the reduced flow & respond as if BP were too low & take steps to raise it further |
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A Diet to Reduce CVD Risk
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• A diet high in saturated fatty acid & trans fat contributes to high blood LDL-C
• Reducing saturated fatty acids & trans fat in diets lowers blood LDL-C & may reduce risk of CVD • Fatty acids & trans fat <10% of total calories; total fat <35%; cholesterol 300 mg/d • Increase legumes, F & V, milk products, whole grains (complex CHO); 2 fish meals/week; fish oils (omega-3) • Flaxseed, flaxseed oil, canola oil, soybean oil, nuts • Increase soluble fiber (oats, barley, legumes, pectin-rich F & V) • Alcohol: one to 2 drinks/day; no binge drinking |
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Chronic High Blood Pressure
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• Target values: 120/80 mm Hg; systolic/diastolic BP
• Risk factors: high blood pressure strongly related to central obesity, atherosclerosis, insulin resistance • Other risk factors for ages 50 – 60 years old: Inherited genes: salt sensitive? Race/ethnicity: Africans, South Asians, Inuit) Environmental factors: stress) • “White coat syndrome” can also occur is when blood pressure increases because one is fearful of the doctor |
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Systolic Vs. Diastolic
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• Systolic: pressure during contraction of heart’s ventricle (large pumping chamber)
• Diastolic: pressure during relaxation, when heart is between beats |
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Nutrition and Hypertension
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• Lose weight, if overweight, & exercise regularly
• Weight loss of 4.5 kg or 10 pounds significantly lowers blood pressure • Moderate physical activity such as walking, jogging, cycling helps in weight loss & reduce high blood pressure directly; raises HDL-C and lowers LDL-C; reduces secretion of stress hormones • Moderate alcohol consumption • In moderate doses, initially relaxes peripheral arteries so blood pressure reduced; high blood pressure leads to cardiovascular disease; alcohol may cause stroke even without high blood pressure • Increase intakes of fruits & vegetables fish, low-fat dairy products • Adequate intakes prevent & correct high blood pressure |
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Nutrition and Hypertension II
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• Decrease sodium/salt intakes
• High dietary intakes of salt & sodium associated with hypertension • Moderately restrict to <2300 mg/d • As salt intakes decrease, blood pressure drops in a stepwise fashion • Salt-sensitive populations such as Africans, people with family history or high blood pressure, kidney problems or diabetes, older people Calcium, potassium, magnesium &vitamin C • Increasing calcium reduces blood pressure • Diets low in potassium-rich fruits & vegetables associated with HBP • Mg deficiency causes artery walls & capillaries to constrict & may raise BP • Adequate vitamin C helps normalize BP • Should diet & exercise fail, diuretics & other antihypertensive agents are prescribed • Most would increase fluid & potassium losses in urine |
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Nutrition and Cancer
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• Foods may cause, promote, or protect against cancer
• Dietary fat, meat, alcohol, excess calories, low intakes of fruits and vegetables, low intakes of fibre are topics of interest in cancer research • Vitamin & mineral research with cancer • Cancer: mutated cells multiply out of control & disrupt normal functioning of one or more organs ◦ 2nd to HD & stroke as a leading cause of death & disability in Canada |
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Cancer Development
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• Cancer is thought to develop through the following steps:
• Exposure of the cells genetic material (DNA) to a carcinogen ◦ Radiation or free-radical compound • Entry of carcinogen into a cell • Initiation of cancer as the carcinogen damages or changes the cell’s genetic material - carcinogenesis • Acceleration by other carcinogens, called promoters, so that cell begins to multiply out of control - tumor formation • Spread of cancer cells via blood & lymph - metastasis • Disruption of normal body functions - cachexia • The first 4 steps are key to cancer prevention |
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Diet and Cancer
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Restricting energy intakes inhibits cancer formation
Excess calories Obesity is linked to cancer of the colon, breast, kidney and esophagus Risk of cancer rises with BMI High fat diets correlate with cancer Saturated fat from red meats and high fat dairy Omega-6 polyunsaturated fatty acids Omega-3 fatty acids protect from cancer and support recovery |
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Acrylamide
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A chemical produced in carbohydrate rich foods when cooked at high temperatures
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Dietary Factors and Cancer Prevention
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Folate deficiency is related to cancer of the cervix and colon
Vitamin A regulates cell division Cancer opposing roles for vitamin D, B6, B12, iron, zinc, copper, selenium & pantothenoic acid Calcium prevents colon cancer |
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Causes of Eating Disorders
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Excessive pressure to be thin
Painful emotions turned inwards genetics |
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Amenorrhea
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Multiple months without a period
Usually occurs with a body fat composition of less than 20% |
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Female Athlete Triad
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Disordered eating
Amenorrhea Osteoporosis |
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Anorexia Nervosa
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Distorted body image that overestimates body fatness
Self starvation and limited portions of low calorie foods Calorie contents and costs are memorized Calorie over estimation is common |
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Anorexia in Athletes
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Loss of lean tissue impairs performance
Heart pumps inefficiently and irregularly Heart becomes weak and thin BP falls Electrolytes go out of balance Death due to heart failure |
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Anorexia Symptoms
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Anemia
Impaired immune response Altered blood lipids High blood concentration of vitamin A and E Low blood protein Dry skin and low body temperature Fine body hair |
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Binge Eating Disorder
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Consume less during a binge, rarely purge and exert less restraint
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