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181 Cards in this Set
- Front
- Back
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T/F About half of the people with hypertension are not sodium sensitive.
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True
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Are sodium, potassium and chloride found inside or outside the cell and are they positive or negative?
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sodium -major positive ion found outside cells
potassium -major positive ion found inside cells chloride -major negative ion found outside cells |
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Calcium _____ is better absorbed by those with low stomach acid because it is ________
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citrate, acidic
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What are the functions of water?
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Temperature regulation
Solvent for reactions, waste removal (≥ 600 ml/d) Metabolic reactions – hydrolysis, electron transport Lubrication, insulation pH maintenance Fluid balance |
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How much of your body weight is water?
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50-70% water
~2/3 |
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How much of muscle is water
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~73%
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How much of fat tissue is water?
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~20%
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How much water is extracellular fluid? -blood plasma, lymph, synovial fluid
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37%
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How much water is interstitial fluid? -blood, bone, muscle, adipose
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63%
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What moves water?
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osmosis- it moves where there are more concentrated ions
it moves through phospholipid bilayers |
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Explain how Na/K ATPase (pump) works
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The Na/K ATPase pump is a membrane transport protein for Na+ and K+
Energy is used to move ions “against” (up) a concentration gradient, and water follows Cells use this mechanism to activate osmosis to maintain water volume electrolyte concentrations As an energy source for transporting other nutrients into the cell (“secondary” active transport, e.g. glucose and amino acids in small intestine) Nerve impulses, etc. |
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How do we intake water?
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Fluids, food, metabolism
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How do we output water?
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Sensible:
Urine, heavy perspiration Insensible: lungs, skin, feces |
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Kidneys reabsorb ___% of water filtered from waste products
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97%
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What is the AI for water?
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AI 3.7 liters (15 cups) for men (2.7 for women) total water intake per day
4.2 glasses/1000 kcal (FNB) from all sources, not just drinking fluids includes water in foods and fluids, and from metabolism, etc. Recommend 1 to 3 liters (13 cups) fluid alone to replace daily water losses. |
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Who is most at risk for dehydration?
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Infants
During illness, especially children with fever, vomiting, diarrhea Elderly During vigorous exercise Airplane passengers |
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Can water be toxic?
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yes, like that little girl who drank a gallon and died
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What does the body do when water levels are low?
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Renin-angiotensin- aldosterone system
kidney senses reduced blood pressure (dehydr.) Renin released Angiotensin II formed aldosterone from adrenal gland to kidney Na retention water retention Blood vessels constricted |
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What are minerals?
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Nutrients that are:
essential to health inorganic (not carbon containing) deficiency results in reduced health health restored when resupplied |
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What is the metabolic role of iron?
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hemoglobin, ETS cytochromes
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What is the metabolic role of Na, K, Ca?
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transfer of nerve impulses, cell integrity, water balance
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What is the metabolic role of Ca?
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bone structure, growth, muscle contraction
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What is the metabolic role of Mg, Mn?
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enzyme cofactors
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What is the metabolic role of I?
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part of a hormone
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What is the RDA/AI for major minerals
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>100mg/day
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What is the a RDA/AI for trace minerals?
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<100mg/day
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Bioavailability
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The degree to which an ingested nutrient is absorbed and available for use in the body.
Depends on many factors: physiological need at time of consumption mineral-mineral interactions same charge, similar size, competition for absorption Zn decreases Cu absorption, Ca supplementation decreases Fe vitamin-mineral interactions vitamin C and Fe vitamin D and Ca, P and Mg Non-mineral substances Phytate, e.g. in unleavened bread binds Zn. Decreased maturation, fertility Oxalate, e.g. in spinach binds Ca, 5% available fiber-mineral interactions fiber bulk |
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What is the best dietary source of minerals?
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an animal/dairy but, fiber free diet
Mg, Mn found in plant based foods |
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How is sodium absorbed and excreted?
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Almost all comes from salt
95% absorbed Excretion regulated by the kidneys |
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What are the functions of sodium?
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Major cation in extracellular fluid
Fluid balance, retaining body fluids Absorption of other nutrients e.g. glucose Nerve impulse conduction Muscle contraction |
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What's the AI and the rationale for sodium?
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AI for adults <51 is 1500 mg/day
Body needs 200 mg/day for phys. functions Rationale: Additional amount allows for a more varied diet Ensures overall diet provides adequate amounts of other nutrients |
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What is the UL for sodium?
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Typical intake
2300-4700 mg/day Na intake used in dietary recommendations NaCl is 40% Na One tsp = 5 g NaCl = ? g Na 40% of 5 grams = 2 grams Note that “salt is not the major cause of hypertension in North America.” UL is 2300 mg/day. About 95% of North Americans exceed Intakes above UL typically increase blood pressure |
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What are risk factors for hypertension?
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Obesity (6x risk)
Inactivity Alcohol (10%) Salt intake |
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What are the requirements for the DASH diet?
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increased dietary K
Rich in fruits and vegetables: 8-10 servings Low in fat and sodium: Low-fat dairy products High fiber (overall a diet high in K, Mg and Ca) Mg - reduces contractile activity in smooth muscle K - most definitive role, inverse association with BP |
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DGA for sodium
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don't eat more than 1 tsp a day
those at risk- hypertension, blacks and older adults don't eat more than 1,500 mg and meet the potassium requirement |
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What are the symptoms of sodium deficiency?
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Rare
Persistent vomiting/ diarrhea Excessive perspiration (losing 2-3% of body weight) Depletion of sodium in the body Muscle cramps, nausea, vomiting, dizziness, shock, coma Normally kidney will respond by conserving sodium |
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What are the functions of K?
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Fluid balance
Nerve impulse transmission, muscle contraction Major cation inside the cell |
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How much of potassium is absorbed?
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90%
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What is the AI for K?
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4700 mg/day
maintain lower BP, blunt effects of Na on BP, reduce risk of kidney stones, decrease bone loss |
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What are good sources of potassium?
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Fruits, juices, vegetables, milk, grains, meats, and dried beans; “whole foods” (intact, unprocessed)
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What are the symptoms of K deficiency?
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Deficiency rare, may occur in people using diurectics, alcoholics, or those with eating disorders.
Life threatening: irregular heart beats muscle cramps/weakness, irregular heart beat (arrhythmias), glucose intolerance |
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Do diuretics increase or decrease the amount of K in the body?
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decrease
at risk for a stroke |
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What are good sources of K/
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still has cells intact
bananas potatoes |
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What is the AI for Chloride?
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AI: 2300 mg/day
Based on Na on 40:60 ratio of Na (1500mg) to balance on a molar basis |
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What are the functions of chloride?
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Functions:
Balances Na positive charges, electrolyte balance Negative ion in extracellular fluid Components of hydrochloric acid (HCl), immune response, nerve function |
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what are the food sources of Cl?
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Food sources: most from salted foods
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What is the UL for Cl?
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UL 3600 mg/day to match Na UL
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What is the function of Ca?
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99% in structural function in skeleton and teeth
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What is the AI for Ca?
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AI:1000-1200 mg/d for adults
Based on balance studies showing intake to offset losses For young people, additional for achieving peak bone density before decline Average intakes 600-800 for women 800-1000 for men 25% of women <300 mg/d |
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What are the food sources of Ca?
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dairy products, kale, collard, calcium fortified foods, canned fish, Tofu (if made with calcium carbonate), mustard greens
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Can increased Ca intake give some people colon cancer?
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yes, some genotypes
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How is Ca absorbed?
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Ca forms the insoluble precipitate Ca(OH)2 above pH 6, so it is not available for absorption very long after pancreatic HCO3- secretions neutralize stomach acid.
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What is the bioavailability of Ca?
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Enhanced by: PTH, glucose, lactose, estrogen, Vit. D
Limited by: fiber (phytic acid) , xs phosphorus, tannins, vit. D deficiency, rapid intestinal motility, achlorhydria, aging, menopause |
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How much Ca do we absorb?
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Normally absorb 25-30% of calcium in food
Increases to ~60% during time of need (pregnancy, infancy) |
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What are the functions of Ca?
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Bone formation and maintenance, teeth
Blood clotting Needed to convert prothrombin to thrombin Nerve impulse transmission Transmitted at the site of the target cell Muscle contraction Cell metabolism Binds with calmodulin Activates various enzymes, i.e. glycogen breakdown Several other possible roles |
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Is Ca part of any hormones?
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osteoblasts- lower blood calcium
hydroxyapatite- with fluoride make teeth stronger osteoclasts- raise blood calcium SHBG- sex hormone binding globulin |
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How does Ca help with blood clotting?
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fibrin formation
vit K-dependent clotting proteins depend on Ca interaction with gamma-carboxyl glutamic acid in the protein Synthesis of osteocalcin for bone formation, same rxn |
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How does Ca help with neurotransmitters?
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Synapse between nerve and target cell
Influx of Ca in response to nerve impulse Fusion of vesicles with membrane Release of neurotransmitters into synaptic cleft Cascade to target cell |
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How does Ca help with muscle contraction?
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**helps actin and myosin slide
Ca storage in smooth ER Ca released from intracellular stores on nerve impulse, the “on” switch. w/ ATP, Ca acts to “walk” myosin along actin Ca returned to smooth ER when muscle relaxed |
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How does Ca help with Calmodulin and cell metabolism?
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**calmodulin complex starts phosphorylation
Regulation of metabolic pathways Calmodulin/Ca complex influences the activity of some enzymes that are key in some metabolic pathways e.g. glycogenolysis |
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What are other Ca effects?
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Decreased risk of colon cancer
Decreased kidney stones Reduced lead absorption Decreased blood pressure Improved blood lipids Possible link with weight loss Reduced PMS symptoms |
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Calcium and weight loss?
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increased dairy leads to weight loss, not necessarily Ca supplementation
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How is blood Ca regulated?
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Every cell needs Ca. Delivered by blood
Highly regulated, hormonal Storage compartment is bones Calcitonin acts in 2 ways to decrease PTH acts in 3 ways to increase |
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What do osteoclasts require to work?
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Requires vit D and PTH, Mg and K.
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What is osteomalacia?
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bone contains too little Ca, linked to insufficient Vit D.
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What are the risk factors for osteoporosis?
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Slim figure
Family history of hip fracture and osteoporosis Genetics control up to 80% of variation Reduced vitamin D receptor activity in small intestine Irregular menstrual cycle Premature menopause xs dietary protein and caffeine (increase Ca loss in urine) Prolonged bed rest |
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How do you prevent osteoporosis?
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get enough vitamin D and Calcium now!
estrogen replacement therapy after menopause- increases cancer risk weight bearing exercise |
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What are the different calcium supplements?
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Ca carbonate (40% calcium):
small pill, Ca concentrated; found in antacids needs good gastric acid production (with or just after meals) not readily dissolved, not as readily absorbed Ca citrate (21% calcium): very large pill is acidic, does not require as efficient gastric acid production, so more efficiently absorbed Recommended for elderly Ca supplements may decrease Zn absorption Avoid interference with Fe absorption-supplement between meals |
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Where is most of the body's phosphorous found?
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80% found in bones and teeth
found in every body cell |
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How bioavailable is Ca?
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Body absorption based on body’s need (70%-90%)
Absorption enhanced by calcitriol (1,25-(OH)2 D3) |
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How is P absorbed?
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Passive absorption based on phosphorus concentration in the lumen, excess excreted by kidney
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What are the functions of Phosphorous?
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Functions include: Bones, teeth, Cellular components (ATP, DNA, RNA, phospholipids), acid/base balance
May be needed in elderly to preserve bone |
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What is the RDA for P and what is the rationale?
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RDA = 700 mg
Assumes 60-65% absorption (typical of mixed diets) Based on intake needed to achieve lower end of range of normal adult serum levels of inorganic phosphate |
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What is the UL for P and the basis?
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UL = 4.0 g/d
Based on upper boundary of normal adult serum levels (NOAEL) |
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What are dietary sources of P?
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Foods - dairy, meats
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What is the deficiency of P?
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Deficiencies highly unlikely
rickets, weakness, bone pain, weight loss, anorexia, decreased growth and tooth development Who could be at risk? Premature babies, alcoholics, long-standing diarrhea, people using Al-antacids |
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What are the symptoms of P toxicity?
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Toxicity - most likely in people with kidney disease
Phosphate ions bind Ca, Ca/P precipitate in body tissues e.g. kidney May contribute to bone loss if Ca intake is low so that Ca/P ratio is imbalanced (e.g. when adolescents substitute soft drinks for milk). |
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What is the function of Mg?
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Functions - >300 enzyme reactions; ATP
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What are the sources of Mg?
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Primarily in green leafy plants, also found in whole grains, veggies, nuts and seeds, dairy, chocolate, meat, hard tap water
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What is the bioavailability of Mg?
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Absorption based on body’s needs (40%-60%)
Absorption enhanced by vitamin D Kidneys regulate blood concentration Alcohol increases loss in the urine Lots stored in the body |
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What is the RDA and UL for Mg?
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RDA = 400-420 mg/d for men; 310-320 for women
Balance studies UL = 350 mg of supplemental Mg No effects of high Mg from food Osmotic diarrhea |
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What are the symptoms of Mg deficiency?
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Deficiency - women more likely to be low; diuretic users
Alcoholism, heavy perspiration, long-standing diarrhea or vomiting Develops slowly; rapid heartbeat, hypertension, weakness, muscles spasms, disorientation, nausea, seizures May increase risk of osteoporosis |
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What are the symptoms of Mg toxicity?
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Toxicity – uncommon
in kidney failure; in supplement users (diarrhea) Weakness, nausea, malaise |
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What are the functions of sulfur?
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Functions: disulfide bridges, acid/base balance, drug detoxifying pathways
Primarily from protein Cysteine, methionine Used to preserve foods |
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Does every trace mineral have an RDA?
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No!
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What is the most important factor that determines iron absorption?
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amount of body stores
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T/F Triiodothyroxine (T3) is the active form of thyroid hormone and regulates basal energy expenditure.
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true
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T/F An essential function in metabolism has not been described for fluoride.
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True
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cretinism
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stunting of body growth and mental development due to iodide deficiency in utero
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ferritin
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protein that serves as storage form of iron in blood and tissues
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mottling
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discoloration or marking of the surfaces of teeth
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goiter
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enlarged thyroid gland due to iodide deficiency
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hypochromic
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pale red blood cells lacking sufficient hemoglobin
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metallothionein
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protein that regulates release of zinc and copper in intestinal and liver cells
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What is the main way a DRI is set for trace minerals?
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balance studies
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What minerals affect Zinc absorption?
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Cu or Fe
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What affects Cu absorption?
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Zn
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What affects Fe absorption?
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Ca
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Does the mineral content of the soil affect the mineral content of the plants?
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yes
some areas of China have high Se, some have low Se not a problem if you eat many different types of food soil depleted? = big fat lie! |
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What minerals are lost changing wheat flour to white flour?
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Fe, Se, Zn, and Cu are lost.
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How is iron absorbed?
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in duodenum and upper jejunum
heme iron: Hb Fe (30% of Fe in meat is absorbed) crosses mucosal cell membrane whole, released non-heme iron: Fe (2 to 10% absorption) oxidation and reduction mucosal block for iron Iron recycled from old RBC in liver and spleen |
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the mucosal block and Fe
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Ferritin synthesized in proportion to iron stores. If stores of Fe low, little ferritin to bind iron, and it is absorbed into blood. If Fe stores high, more is held 2-5 days by ferritin until mucosal cells are sloughed off.
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what are the functions of iron?
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hemoglobin O2 transport in blood
myoglobin O2 binding in muscle cytochromes Electron Transport System many other Fe-containing enzymes Immune function, drug-detoxification pathway, cognitive development, temperature regulation |
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What are iron deficiency symptoms?
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Fatique: decreased O2 delivery and ETS
Iron deficiency (marginal Fe deficiency, can lead to fatigue by effect on ETS alone) Iron deficiency anemia Lack of organ system development Lack of cognitive development |
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hematocrit
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percentage of total blood volume occupied by red blood cells.
anemia: < 34 to 37% |
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microcytic hypochromic anemia
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2-5% of adolescent girls and women in US have Fe deficiency
much greater in developing countries pale skin, brittle fingernails, fatigue, weakness, breathing difficulty with exertion, inadequate temperature regulation, loss of appetite, apathy. |
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RDA & UL basis for Iron
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Based on balance for losses
RDA: 18 mg/d for women, 8 mg/d for men Assumes 18% absorption Avg. intake > RDA for men, < RDA for women Most women consume < RDA not all need this much RDA sufficient for 98% of population Differences in menses, Fe absorption UL = 45 mg/d, based on GI distress |
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what are the symptoms of iron toxicity?
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UL 45 mg/day
Stomach irritation Free radical formation because of valence considerations Excess iron deposited in muscles, pancreas, heart and liver, leading to organ damage Hemochromatosis -“mucosal block” less efficient 1 in 200-500 Americans homozygous 1 in 9 (of European ancestry) heterozygous Fortification – should it be increased? |
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Describe the Absorption of Zinc and Copper, and the Role of Metallothionine
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Zn absorption induces metallothionein in intestinal cell.
Binds Zn and Cu like ferritin binds Fe. Zn is transferred to blood transport proteins based on the body’s need for Zn, not on how much is in the intestinal cell. If not needed, it is sloughed off with cell in 2-5 days forming a mucosal block large doses of Zn override block |
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How is Zn absorbed?
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What dietary constituents affect Zn absorption?
Oxalate – spinach, chard, berries, chocolate, tea Phytate – maize, whole grains (bran), legumes Ca supplements inhibit Interacts with Cu absorption Competes with Fe absorption Excess excreted by pancreas to feces (unlike Fe) |
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What are the functions of Zn?
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50-200 enzymes require Zn as cofactor
DNA, RNA synthesis Protein metabolism, related growth and development Superoxide dismutase (antioxidants enzyme) Cell membrane stabilization Wound healing, immune function; development of sex organs and bones Other enzymes: e.g. carbonic anhydrase, alcohol dehydrogenase Insulin storage, release, functions Gene transcription factors (zinc fingers) |
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symptoms of Zn defiiciency?
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Dietary content not low
Unleavened bread consumed contains high concentrations of phytic acid which chelate much of what little Zn is in the diet, and binds it strongly enough that it is not absorbed. The activity of yeast during leavening of bread destroys phytic acid in raised bread. Acrodermatitis enteropathica – genetic impairment of Zn absorption Skin condition that develops in infancy |
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what are the sources of Zn?
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Animal products, shell fish, legumes
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RDA basis for Zn
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RDA rationale: replace daily loses, factorial (balance) approach
Men: 11 mg/d; women: 8 mg/d Avg. intake marginal for women, adequate for men Other acute deficiency symptoms: reduced sense of smell and taste acne-like rash lack of appetite Those at risk of deficiency: malabsorption problems, protein-energy malnutrition, sickle cell disease, alcoholics, anorexics, elderly, pregnant women, |
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Why is zinc toxic at only 3-5 times the RDA?
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Long term high Zn intakes, greater than 3-5 times the RDA, inhibit copper absorption by overly stimulating synthesis of metallothionein, used as a mucosal block.
Decreased Cu status @ 50 mg/d of Zn for 10 wks UL based on adverse effects on Cu status, enzymes UL = 40 mg GI distress @ 50-150 mg (5-50X RDA) suppl. Zn (diarrhea, cramps, nausea, vomiting) 50-150 mg/d may decrease HDL Mineral supplements should not be consumed in excess except under close scrutiny of a physician. |
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What are the functions of Cu?
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Cu functions in many enzymes systems
Fe transport: ceruloplasmin elastin and collagen cross-linking (lysyl oxidase, connective tissue and vessel walls) aneurysms result from severe Cu deficiency neurotransmitter synthesis: norepinephrine immune system, blood clot, brain development, cholesterol metabolism antioxidant enzymes, superoxide dismutases (SOD) ETS: in cytochromes of cytochrome oxidase; redox reactions. |
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symptoms of Cu deficiency?
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Deficiency: usually consequence of Zn supplementation; decreased Cu stores at birth, poor abs., elevated needs, or increased losses
Normocytic, hypochromic anemia (Why?), one WBC low, bone loss, inadequate growth At risk: undernourished or preterm infants, dialysis or burn patients, excess Zn suppl. Marginal Cu def. being studied: low immune system, poor resistance to oxidative stress |
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symptoms of Cu toxicity
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Toxicity not common
Wilson’s disease (genetic disorder of Cu excretion) accumulates Cu in the liver, brain, kidneys, and cornea; fatal if left undetected Liver damage (UL 10 mg, based on liver damage) Aqueous Cu at 10-15 mg tends to cause vomiting |
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Food sources of Cu
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Food sources:
organ meats, seafood, cocoa, mushrooms, legumes, seeds, and nuts, whole-grains |
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basis for Cu RDA
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RDA = 900 ug/d; ave. intake 1-1.6 mg/d
based on plasma ceruloplasmin, RBC superoxide dismutase |
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absorption of Cu
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dependent on body’s needs
absorbed in duodenum, excess excreted via bile absorption decreased by high Zn suppl., can result in severe Cu deficiency |
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bioavailability of Se
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Readily absorbed, high bioavailability, no regulation, excretion via urine and feces
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food sources of Se
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fish, meats, eggs, milk, shell fish, grains, seeds, nuts (dependent on soil content)
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basis for RDA of Se
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RDA = 55 ug/day, avg. intake exceeds RDA
Based on plateau in plasma glutathione peroxidase activity |
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functions of selenium
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Glutathione peroxidase (enzymatic antioxidant)
spares vitamin E Thyroid hormone metabolism (T4 to T3) Effect on rate of metabolism Other antioxidants (e.g. thioredoxin) Other selenoproteins of unknown function Se alone is NOT an antioxidant |
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what are the symptoms of Se deficiency
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Deficiency - muscle pain, wasting, cardiomyopathy;
At risk: dialysis patients, TPN patients, some local soil users Keshan disease (irreversible) – Se protective, not curative. cardiomyopathy and accumulation of fatty acid peroxides in heart in children; soil Se deficiency in areas of China, Finland and New Zealand |
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symptoms of Se toxicity
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Toxicity - hair & nail brittleness & loss; nausea, vomiting, weakness, rashes, liver cirrhosis, garlicky breath
UL = 400 ug/d Some plants are Se accumulators Custer’s reinforcements did not arrive at the Little Big Horn when mules and horses consumed astragalus (Se concentrators) in Northern Wyoming Se and cancer, role in antioxidant enzyme systems |
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Is Se alone an antioxidant?
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no, it has to be bound to amino acids
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Where is iodide absorbed?
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Absorbed along GI tract, including stomach (unusual); transported free or bound to proteins in the blood
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functions of Iodide
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Thyroid hormone (thyroxine, T4) synthesis
T4 a “prehormone”, converted to T3 in target cell. T3 in cell regulates metabolic rate, growth, development Development of the CNS Binds to DNA receptor |
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RDA basis for iodide
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RDA = 150 ug/day (50 ug prevents goiter), avg. intake exceeds RDA (not including iodized table salt).
Based on thyroid iodine accumulation and turnover |
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food sources of iodide
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Saltwater fish, seafood
Iodized salt (1/2 tsp. meets RDA) milk: I used as sterilizing agent baked goods: I used in dough conditioners food colorants Plant content depends on soil content not “natural” sea salt from supplement stores. I is removed during processing |
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symptoms of iodide deficiency
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Deficiency:
continual release of TSH, goiter, drop in metabolic rate, cretinism World War I draftees from Great Lakes and Pacific Northwest Define goitrogens. consumption of goitrogens inhibits iodide metabolism in thyroid gland (raw turnips, cabbage, brussel sprouts, cauliflower, broccoli) goitrogens destroyed by cooking |
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symptoms of iodide toxicity
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Toxicity: UL set at 1.1 mg/day (based on increased TSH above baseline)
High I inhibits thyroid hormone synthesis, “Toxic goiter” results, consumption of seaweed |
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Thyroid stimulating hormone and goiter development
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Pituitary gland senses lack of thyroxine, secretes TSH
TSH stimulates growth of thyroid gland to produce more thyroxine Thyroid can’t produce thyroxine because it has no I, so the cycle continues. 2 billion people in the world are at risk for deficiency, 200 million have goiter. |
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iodide deficiency and cretinism
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I deficiency in early (first 4) months of pregnancy
T3 role in CNS development Infant with short stature, mental retardation Maternal I needs take precedence over fetal I needs. 50 million people have preventable brain damage from maternal I deficiency. Major preventable cause of mental retardation worldwide. |
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functions of fluoride
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Essential function has not been described other than dental caries (definition of essential?)
Dental caries prevention Aids in synthesis of fluorapatite crystals Fluoridated water (1ppm) Fluoride in saliva bathing teeth Stimulates osteoblasts; a treatment for osteoporosis? (Ref 1, ADA, “bone and teeth health”) |
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how is fluoride absorbed and stored
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Passive diffusion throughout the GI tract, most in stomach, excreted through the kidneys via urine
Stored in calcified tissue (teeth, bones) |
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explain fluoride and cavity prevention
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Lower incidence of caries in areas with fluoridated water systems
Fluorapatite (bone and teeth hydroxyapatite with fluoride interspersed in crystals) more acid-resistant. Reduces acid solubility, promotes remineralization, incr. deposition, reduces rate of transport. Fluoride excess causes “mottling” of teeth. Even more results in skeletal fluorosis (crumbling). |
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sources of fluoride
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Fluoridated water (~0.2 mg/cup), tea,seafood, seaweed, toothpaste
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AI for fluoride and basis
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AI: men = 3.8 mg/d; women = 3.1 mg/d
Based on relationship between water F and dental caries |
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fluoride toxicity and basis
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Toxicity: UL is 10 mg/day
Mottling of teeth in children In high amounts can weaken teeth in children Fluorosis : poor tooth structure, discoloration of teeth |
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functions of chromium
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Glucose uptake
Enhances conversion of glucose to fat Impaired glucose tolerance with low intake Elevated cholesterol and triglycerides with low intake (sensitive measure of Cr status not available) 0.5-2% of chromium from food is absorbed, excretion via the feces Concentration of chromium very low in the body Binds to transferrin in the blood |
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chromium and glucose tolerance
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Cr increases insulin activity in glucose uptake, possibly by increasing insulin receptor activity in target cells.
Some marginally deficient in Cr; may contribute to type II diabetes Claims made for Cr picolinate (increased muscle mass,decreased fat mass) not based on scientific evidence. |
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food sources of Cr
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Food Sources
AI is 25 - 35 ug/day; based on estimated mean intakes in healthy diets; avg. intake meets AI Egg yolk, mushrooms, bran, cereal, organ meat, meat, beer |
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Cr toxicity
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Toxicity (no UL) – few serious effect of high food Cr
Exposure to Cr waste sites Lung damage, skin allergies, ulcers, convulsions, kidney damage, liver damage, cancer, death Chromium picolinate – free radical production? |
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functions and toxicity of Mn
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cofactor for many enzymes, bone formation
AI based on median intakes in FDA Total Diet Study No deficiency symptoms observed in humans Toxicity seen in individuals working in manganese mines: Severe psychiatric abnormalities, violence, impaired muscle control |
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functions of Mo
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xanthine oxidase and xanthine dehydrogenase
RDA based on Mo balance in controlled studies roles in gout (uric acid formation) high intake inhibits Cu absorption |
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Boron
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fruits, leafy veggies, nuts
“not shown to have a sufficiently definitive pattern of effects to establish a function” (NAS 2000) Metabolism of steroid hormones (vitamin D, estrogen)? |
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Nickel
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nuts, beans, grains, chocolate
“No biochemical functions clearly demonstrated in higher animals or humans” (NAS) Deficiency signs in several species: Ni is an essential trace element in animals Activates enzymes – BCAAs, B12, folate, met |
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Silicon
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plants, unrefined grains, cereals, root veggies
involved in bone formation in small animals (chickens, rats) deficiency could effect brain and bone formation, atherogenesis? |
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Arsenic
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fish, grains
Role in methionine metabolism? Poisonous, need in trace amounts Gene expression of stress proteins |
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Vanadium
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shell fish, mushrooms, grains
Enhances enzyme activities mimics insulin – stimulates cell proliferation, differentiation |
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Which of the following accounts for the greatest percentage of energy requirement?
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basal metabolism
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Human energy use can be estimated by indirect calorimetry, which measures
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oxygen consumption
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T/F Appetite is defined as the primarily physiological drive that encourages food consumption.
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False
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What type of fat distribution is associated with an increased risk of hypertension, CVD, and type 2 diabetes?
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android obesity
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ghrelin
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hormone made by the stomach that stimulates eating
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leptin
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hormone made by adipose tissue that influences long-term fat regulation
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underweight
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body mass index below 18.5
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thrifty metabolism
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metabolism that conserves more energy than normal
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endorphins
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the body's natural opiod pain killers
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stimulus control
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altering the environment to minimize the stimulus for eating
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energy balance
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Components of energy intake
Components of energy expenditure Change in energy stores “Let the refrigerator replace the need to store body fat—food is always at hand.” Availability Larger portions |
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4 types of energy expenditure
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Basal metabolism (BMR, RMR)
Physical activity (PA) Thermic effect of food (TEF) Adaptive thermogenesis (NEAT) |
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BMR/BEE
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Resting, awake, not aroused
no food intake in 12 hours warm, quiet environment 60-70% of TEE heartbeat, respiration, body temperature, organ activity |
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RMR/REE
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aroused but resting
6% difference “kcal/kg” method Males: 1 kcal/kg/hour Females: 0.9 kcal/kg/hour |
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Harris Benedict Equation
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REE = (655.1 + (9.6*WT) + (1.9*HT) - (4.7*AGE)
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Determinants of BMR/RMR
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body composition - lean body mass increases
body surface area - increases gender- males increases/females decreases body temperature- increases 7% per degree F Thyroid hormone- increases nervous system activity- increases Age- decreases 2% per decade after 30 Decreased energy intake - decreased 10-20% Pregnancy - increases caffeine and tobacco- increases |
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Thermic Effect of Food
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GI transit, digestion, absorption, packaging, transport of nutrients; waste excretion
Estimate 10% of total Kcal intake or 10% of BMR + PA expended Different for different foods protein-rich meal, 20-30% of energy consumed. CHO rich-meal 5-10%. fat-rich meal, 0-3%. |
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Thermogenesis
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NEAT, shivering or fidgeting
Production of heat in response to a cold environment (in animals and neonates) and to overfeeding. Some animals and human neonates have brown adipose tissue which uncouples oxidation and phosphorylation to produce heat rather than ATP in mitochondria, using uncoupling protein 1 (UCP1). Humans have UCP2&3 in muscle which make the ETS less efficient. Regulation and relation to energy balance is being studied. |
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Respiratory Quotient
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RQ is the ratio of CO2 produced to O2 consumed (CO2 / O2)
Genetics affects use of fuel, RQ, risk of obesity. Dietary intake of energy nutrients also has an effect on RQ, because it alters use of fuels. higher for glucose than fat |
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+/- of BMI
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Correlates with health risks for populations
Less useful for: Elderly, Preg & lactating, Athletes Does not tell % body fat |
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DEXA scan
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Considered most accurate
And expensive Not widely available Provides three compositions Fat mass Fat free soft tissue Bone mineral density |
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hunger
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primarily physiological drive to find and eat food.
Internal stimuli. regulated by: organ nutrient receptors, nerves (vagus), hormones, neuroendocrine factors and receptors. |
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Appetite
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primarily psychological influences that encourage us to find and eat food, often in the absence of hunger. "When food is ample, appetite-not hunger-mostly triggers eating
external stimuli affected by: visibility, availability, color, temperature, emotional state (stress, boredom) social (decreases risk) |
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Leptin
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Made in adipose
Targets hypothalmus, others Causes satiety w/ incr stores Energy conservation during decr. food supply Decreases activity of neuropeptide Y |
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CCK
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Made in duodenum
Decr. intake, brings satiety. ↓ in bulimia |
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Ghrelin
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Made in stomach, GI
stimulates food intake |
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Neuropeptide Y
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Made in brain
increases intake, decreases expenditure regulated by leptin |
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consequences of weight cycling
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Possible consequences
Increased risk for upper-body fat deposition Erosion of self-esteem Decrease in HDL Decrease in immunity Increase in fat/lean ratio |
