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146 Cards in this Set
- Front
- Back
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Nutrient
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Substance in food providing structural or functional components or energy to the body
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Essential Nutrient
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Nutrients that must be obtained from diet, body doesn't make them
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Macronutrient
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- Needed in large amounts
- Grams daily - Fats, carbs, proteins - Recommendations follow the AMDR (Acceptable Macronutrient Distribution) |
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Micronutrient
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- Needed in small amounts
- Milligrams daily - Vitamins, minerals |
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Fiber
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Not technically a nutrient because it is not in a metabolic pathway, but useful and needed
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Dietary Reference Intakes (DRI) - 4
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- Dependant on AGE
- EAR (Estimated Average Requirements) - RDA (Recommended Dietary Allowance) - UL (Tolerable Upper Limit Intake Level) - AI (Adequate Intake) |
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EAR (Estimated Average Requirement)
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- Average value which is used as a starting point for calculating an RDA
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RDA (Recommended Dietary Allowance)
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- Specific for different populations, specifically age
- EAR + 2 STD |
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AI (Adequate Intake)
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- Recommended intake level for use when RDA IS NOT AVAILABLE
- Use me when data SUCKS |
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UL (Tolerable Upper Intake Level)
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- MAXIMUM level of daily nutrient intake unlikely to impose risk
- Level at which it's okay, beyond which bad stuff happens. |
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Acceptable Macronutrient Distribution Range (AMDR)
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- Levels for Macronutrients
- FATS: 20-35% - CARBS: 45-65% - PROTEIN: 10-35% |
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Vegetarian Nutritional Concerns
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- Deficent in some AA's
- Diet must be carefully crafted - Vitamin B12, D, Calcium Deficiencies - Zinc deficency |
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Basal Energy Rate (BMR)
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- Energy needed to carry out fundamental metabolic functions
- Measured in RESTING state |
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How does BMR vary in a population?
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- Age
- Sex (men > women) - Peak in infancy |
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General Nutrition in Infancy
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- IDEAL: Human Milk
- Must provide for the greater metabolic needs and growth rate of individuals |
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General Adolescence in Childhood
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- Varied diet from all food groups
- Major concerns are iron, calcium deficency |
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Acceptable Macronutrient Distribution Range (AMDR)
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- Levels for Macronutrients
- FATS: 20-35% - CARBS: 45-65% - PROTEIN: 10-35% |
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Vegetarian Nutritional Concerns
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- Deficent in some AA's
- Diet must be carefully crafted - Vitamin B12, D, Calcium Deficiencies - Zinc deficency |
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Basal Energy Rate (BMR)
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- Energy needed to carry out fundamental metabolic functions
- Measured in RESTING state |
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How does BMR vary in a population?
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- Age
- Sex (men > women) - Peak in infancy |
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General Nutrition in Infancy
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- IDEAL: Human Milk
- Must provide for the greater metabolic needs and growth rate of individuals |
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General Nutrition in Childhood
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- Varied diet from all food groups
- Major concerns are iron, calcium deficency |
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Food Allergy vs. Food Intolerance
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Simplified, immune response vs. non-immune response (enzyme deficiency)
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General Nutrition in Adolescence
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- Intense Anabolism (growth spurts)
- Food habits can cause nutrient deficiencies - Eating Disorders, Obesity |
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General Nutrition in Elderly
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- Appetite decreases can lead to nutrient deficiencies
- Vitamin D, Calcium, Protein, Vitamin B12 - Social factors, physical limitations, sensory changes - Drug Interactions |
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1 Calorie vs 1 calorie
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1 Calorie = 4.184 kJ = 1 kcal = 1000 calories
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Basic Metabolic Rate (BMR)
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- Rate per hour we burn calories AT REST
- Can be divided by the person's weight in kilograms for units kcal/kg-hr |
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Total Energy Expenditure (TEE)
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- Total calories expended during the course of one 24-hour day
- 60% is basal metabolism (BEE) |
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Basal Energy Expenditure (BEE)
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BMR * 24hours
Units: kcal/hour |
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Resting Metabolic Rate (RMR) and the Resting Energy Expenditure (REE)
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- RMR is NOT at rest, but close enough
- REE is analogous to BEE except it is NOT at basal levels. |
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Harris-Benedict Equations
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Way we can ESTIMATE the BMR for an individual
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Indirect Calorimetry
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- Way we can MEASURE the BMR/RMR for an individual
- Measure O2 consumption and CO2 production... do this by multiplying liters by this. - O2 = 4.9 - CO2 = 5.75 |
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Respiratory Quotient
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- We can use the ratio of CO2/O2 to tell us what proportion of calories used comes from fat, and what comes from carbohydrates
- We can also measure this ratio to give us RMR. |
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RQ for Carbs, Protein, Fats
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Carbs = 1
Fat = 0.71 Protein = 0.82 |
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Caloric Content of Carbohydrates
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4 Cal/g
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Caloric Content of Fats
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9 Cal/g
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Caloric Content of Protein
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4 Cal/g
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Caloric Content of Ethanol
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7 Cal/g
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How do you LOSE WEIGHT?
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Expend more calories than you take in.
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Physical Activity Ratio (PAR)
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- Express it as a multiple of BMR
- Indicates how much faster energy is being expended doing that activity than under basal conditions |
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Calculating TEE (Total Energy Expendature) for Normal People
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- Need BMR or RMR estimation
- Need duration of physical activity TEE = (BMR * 24hrs) + (PAR * Time) * 1.10 |
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Thermic Effect
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Heat produced by the body accompanying food digestion
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Calculating the TEE (Total Energy Expenditure) For SICK PEOPLE
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TEE = BMR x Injury Factor x Activity Factor x 1.1 (the thermic effect) x 24 h
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Hypercatabolic State
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Hormones rise that cause increase in protein breakdown, gluconeogenesis, and glyconeolysis.
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Injury Factor
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What we need to multiply the TEE by for sick patients
Trauma 1.4 Sepsis 1.6 Burns 2.1 |
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Reactive Oxygen Species
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- Toxic by-products causative of pathologies
- Superoxide, Hydrogen Proxide, Hydroxyl Radical - MUST react where generated |
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ROS and Lipids
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- Chain reaction makes lipid radicals with unsaturated fatty acids
- Continue chain.... |
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Oxidative Stress
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- Pro-oxidant conditions lead to production of ROS more rapidly than antioxidant defenses can consume them
- Cell damage, cell death |
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Major Source of ROS
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- Mitochondria
- Complex IV, if it doesn't get 4 electrons, will form this |
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Respiratory Burst
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- Some leukocytes when stimulated make superoxides
- Destroy microbacteria - Inflammatory response |
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What do ROS play a role in?
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- Disease
- Immune Response - Cancer |
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Lipophilic Antioxidant Purpose (Vitamin E)
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- Chain breaking antioxidant
- Remember lipid carbon-centered radicals? It stops that. - Lipid Soluable |
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Where is Vitamin E found?
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- Grains
- Wheat - Vegetable Oils |
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Problems with Vitamin E
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- If you have TOO MUCH of it, it can compete with Vitamin K
- Lowers Vitamin K activity - Bleeding |
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Vitamin E Structure
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- Lipid Soluable
- Ring structure is "activity" site - Has saturated side chains, methyl groups on ring contribute to diversity and activity - Alpha = Natural |
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Hydrophilic Antioxidant Vitamin
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Vitamin C
Ascorbate |
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Vitamin C Importance
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- Protects against oxidation of water-soluble components
- "Detoxifies" - Returns Vitamin E to reduced state.. impacts membrane components too indirectly - NO VITAMIN C: SCURVY, slow wound healing... |
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What does Vitamin C effect?
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- Lowers DNA oxidation
- Lowers Membrane Oxidation - Possibly lower heart disease, might help smokers |
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Glutathione Peroxidase
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- Another way ROS is combatted
- Catalyze reduction of Hydrogen Peroxide to Water through GSH to GSSG - Also breaks down lipid peroxides - Selenium at active site |
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Selenium
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- Required for GSSG reduction to GSH by NADPH so that we can get glutathione back
- Essential, but not an antioxidant.. antioxidant cofactor |
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Superoxide Dismutases
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- Dismutation of superoxide to Hydrogen Peroxide and Oxygen
- AEROBIC ORGANISMS - Requires Cu/Zn - Lou Gehrig's Disease |
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Catalases
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- Also combats ROS species
- Hydrogen Peroxide to water and oxygen - Hemoprotein, located in peroxisomes |
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Glutathione
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- Intracellular reductant
- Exists as GSH - Helps with ROS |
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Flavonioids
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- Dietary compoud that might provide antioxidant protection
- Green Tea, Blueberries, Red Wine |
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Urate
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- In blood
- Stabilizes Vitamin C (asorbic acid) and acts as a radical scavenger |
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Thiamin (Vitamin B1)
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- Cofactor in a lot of reactions (TPP in PDH)
- Coenzyme in carbohydrate metabolism - Glucose metabolism in brain, muscle, CNS |
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Beri Beri
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- Thiamin deficency
- Muscle Weakness, ataxia - "Wet" Beri Beri displays pitting edema |
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Wernicke-Korsakoff Syndrome
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- Weak TPP binding, manifests if not getting enough thiamin in diet
- Basically beriberi + CNS problems - Seen in alcoholism |
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Where can we get Thiamin?
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Grain cereals, pork
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Niacin (Vitamin B3)
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- NAD, NADPH
- Made from tryptophan (part of our Niacin requirement from this) - Dehydrogenase reactions, substrates, precursors |
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Where can we get Niacin?
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Lean meats, fish, cereal, poultry
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Pellagra
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- "Three D's - Diarrhea, Dementia, Dermatitis...DEATH"
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Excess B3 will cause....
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- Flushing, biochemical abnormalities
- If we give a LOT, we can reduce elevated cholesterol levels - PELLAGRA |
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Folic Acid
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- One Carbon Donor
- Purine deNovo Synthesis - The "folate pool" is complex, know that it mostly gets converted to 5-methyl THF to be put into a pool |
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Where can we get Folate from?
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- Dark green leafy vegetables
- Legumes - Fruits |
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Neural Tube Deficiency
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- Not enough folate in the early stage of pregnancy leads to defects
- Combated by prenatal vitamins |
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Inadequate Folate Intake
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- Serum Folate Drops
- RBC Folate Drops - Hypersegmented Neutrophils - MCV drops - Hemoglobin Drops AKA ANEMIA |
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Macrocytic Anemia
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- RBC are larger than normal
- Folate deficiency inhibits DNA synthesis - No bumps on tongue - So we have huge RBC, not enough of them, and crappy hemoglobin levels |
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Hyperhomocysteinemia
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- Accumulation of Homocysteine
- If you have crappy levels of folate, then you have crappy levels of 5-methyl THF, and homocysteine is used to convert that into THF |
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Vitamin B12
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- Helps convert 5-Methyl THF to THF
- Helps convert methylmalonic acid to Succinyl CoA |
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What's BAD about B12 deficiency?
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- Folate is "TRAPPED" since B12 is fundamentally required to get folate turned into other things useful for bodily biochemical processes
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What's BAD about too much folate?
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- Too much folate can "mask" a B12 deficiency, as it can be converted to THF in excess
- B12 eventually leads to neuropathys which are irreversible |
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Pernicious Anemia
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- Autoimmune B12 deficency
- Cannot synthesize IF - Poor absorption of B12, so anemia |
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How is B12 absorbed?
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- INTRINSIC FACTOR in stomach
- R-proteins bind to it in stomach and then unbind in the ileum, where it is efficiently absorbed - We have "stores" of B12 that will last us years as long as stuff isn't damaged |
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Where do you get B12?
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- Eggs, dairy products, fish, meats
- Vegans at risk, old people at risk |
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Vitamin B6
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- Glycogen breakdown
- Precursor to biologically active form, PLP - Possibly involved in steroid synthesis |
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Where can we find Vitamin B6?
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- Wide distribution
- Poultry, fish, vegetables |
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Excess consumption of B6
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- Pellagra-like syndromes (DDD)
- Toxic irreversible neuropathy |
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Riboflavin (B2)
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- Think of the enzyme prosthetic groups FMN and FAD
- Redox Reactions - Angular Stomatitis (kinda like the Joker Smile) |
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Biotin
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- Prosthetic group for carboxylation reactions
- If you eat too many eggs, "ROCKY SYNDROME", you can cause this because of the protein in it which has a strong biotin affinity |
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Where can we get riboflavin, biotin, and panthoenic acid?
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Pretty much everywhere, which is why having deficiencies in them is so rare
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Panthothenic Acid
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- Helps create Coenzyme A
- Cooking destroys it |
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Inadequate Uptake
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- Alcoholism
- Avoidance of foods - Calories, protein lacking - B Viamin Deficencies - Wernicke-Korsakoff syndrome |
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Inadequate Absorption
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- Malabsorption
- Drug-nutrient interactions - Not enough vitamins |
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Decreased Utilization
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- Drug-nutrient interactions
- Isoniazid: drug that reduces PLP |
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Increased Losses
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- Diarrhea, Blood Loss
- Water, Iron Loss |
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Increased Requirements
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- Fever, Pregnancy
- "Feed a cold" .. increased caloric needs because of catabolism |
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Anthropometric Measures
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- Physical measures of weight or dimensions of the human body
- Good for establishing nutritional status especially in children |
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Height & Weight
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- Observed over time
- Measured by Stadiometer |
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Hamewi Rules
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- Compare someone's BW against the desirable weight
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BMI
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- Weight (KG)/Height (meters)
- Most useful in adults with a normal build |
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Malnutrition
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- INVOLUNTARY WEIGHT LOSS of 10% or more over a six-month period
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Why Measure Head Circumference?
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- Non-nutritional abnormalities
- Severe malnutrition: the head will be bigger relative to chest due to wasting of muscle and fat in chest wall - Useful for under the age of 3 |
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Skinfold Thickness
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- Estimate subcutaneous fat deposition
- Not useful in acute setting |
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Where are the Albumin's made?
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- LIVER!!!
- So affected by liver disease |
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What biochemical measurements are useful in a nutritional exam? (HINT: LAB TESTS)
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- Electrolytes
- Lipid Profile - Serum Albumin/Prealbumini/Transferrin - Hemoglobin - CHI |
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Serum Albumin
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- Common visceral protein
- Useful for hospital admissions... not useful if ongoing - What's their risk of morbidity or mortality due to malnutrition? - Slow to change with recent dietary modifications, has a long half-life - Susceptible to clinical conditions.. like the liver |
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Serum Prealbumin
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- Transthryetin
- Half-life of 2-3 days.. measure of choice in the hospital - Affected by liver failure |
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Serum Transferrin
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- Half life of 8-9 days, maybe useful for cumulative nutritional status over intermediate time interval
- IRON affects it - Affected by liver failure |
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Createnine Height Index (CHI)
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- Estimate of skeletal muscle mass
- Urinary levels depend on the extent of muscle catabolism CHI = mg creat 24 hrs/mg normal subject of same height sex Affected by liver failure |
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NPO
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- Nothing BY Mouth
- They can still eat: liquid diet by stomach (TPN), intravenous (PPN) |
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What do the brain and RBC use for their primary energy source?
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CARBOHYDRATES
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What are the functions of carbohydrates in general?
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- Largest source of dietary caloric intake
- Important for certain tissues energy source - contribute to taste, texture, preservation of foods |
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Where are carbohydrates found in our diet?
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Plants, fruits, vegetables, grains/cereals
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Complex Carbohydrates
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- Starch (we can digest if we cook it)
- Cellulose (we can't digest because we don't have enzyme to break beta bonds) - Broken down into limit dextrins |
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Simple Carbohydrates
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- Refined sugars, like table sugar, HFCS
- Sucrose (Glucose + Fructose) |
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Why is HFCS bad?
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- Possibly contributes to obesity
- By-passes glycolysis - Possible high fructose/glucose ratio increases lipogenesis |
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Sugar Alcohols
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- Sorbitol
- Poorly absorbed, aimed at those trying to avoid caloric intake - Marketed toward diabetes patients, but sugar alcohols can build up - Can cause eye damage, kidney damage |
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AMDR and RDA values for Carbohydrates
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AMDR: 45-65%
RDA: 130g (minimum amount for brain). We get a lot more than this though |
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Isomaltase
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Debranching enzyme in our stomach and pancreas that gets rid of limit dextrins. Recall: carbs are almost 100% effectively absorbed and metabolized (RQ = 1)
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Where does digestion begin? Where does it end?
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- Begins in MOUTH with alpha amalyse
- STOPS in the STOMACH (pH issues) - Ends in the SMALL INTESTINE where it is completed |
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Alpha Amylase
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- Hydrolyzes ALPHA 1,4 glycosidic linkages
- Present in the mouth - Cellulose not digested well because of this |
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Pancreatic Glysosidases
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- Digestion re-resumes in the stomach because alpha amalyse is inactivated by stomach pH
- Continues getting rid of dextrins - Still can't digest cellulose |
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Unavailable Carbohydrates
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- Carbs that can't be enzymatically digested
- Pass into Large Intestine, are excreted - Celluose |
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Lactose Intolerance:
What are the primary and secondary causes? |
1) Missing Lactase
- Helps hydrolyze LACTOSE into Galactose and Glucose 2) Stomach Surgery, stomach diseases |
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Who is affected by Lactose Intolerance?
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- 75% of adults
- Actually begins in infancy when we are being weaned from milk - Common in Asians, not so much in Europeans - Common in US because we're so |
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Lactose Intolerance
Consequences |
- Abdominal Bloating, cramping, gas, diarrhea
- Why? Bacteria tries to metabolize lactose (does, into gas) ... osmotic effect of colon. |
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Lactose Intolerance
Treatment |
- Avoid dairy products
- Take supplements pre-treated with lactase - "Train" your body slowly to tolerate some, but not a lot |
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How is fructose absorbed?
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- Through own transporter: FRUC5
- Facilitated diffusion |
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How is Galactose and Glucose absorbed?
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- Secondary Active Transport (depend on Na/K ATPase
- SLGT - Why sodium-glucose drinks are used to rehydrate. |
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How does fructose, galactose, glucose exit enterocytes?
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- Facilitated Diffusion
- Transporter, GLUT2, at basolateral membrane... enter circulation and are metabolized in liver |
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What is fiber composed of?
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- Non-starch plant polysaccharides and lignin
- Found in plants, cell walls |
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Insoluble/Soluble Fibers
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- Metabolized by gut bacteria
- Get them from whole grains, apples, fruits, gums - Insoluble fibers: cellulose (legumes) nad lignin |
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Why is fiber important?
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- Absorb water, increase speed of digestion and absorption, increasing satiation
- Enlarge and soften stools, shorten transit time - Slow glucose absorption, reduce peak BGL after meal - Bind bile acids |
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Glycemic Response
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- How fast and how far BGL rises after a meal is eaten
- Easier to eat and digest, higher the response - Fibers "blunt" this response by reducing the BGL peak (it's hard to digest them) |
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Glycemic Index
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Raking of foods based on glycemic response
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Glycemic Load
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GL = GI(%) * carbs(g)
- How much a typical food will raise BGL - A bit of a misleading thing. Ex, carrots might have a high GI, but they have a low carb amount. |
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Hypocholesterolemic Effect
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- Fiber binds bile acids
- We have to make them now to digest things, and they're derived from cholesterol - Effectively lowering cholesterol - Fiber can help lower the risk of heart disease this way |
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Fiber Daily Recommendations
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- 25-35g a day
- Ratio of 3:1 insoluble:soluble Average US diet does not meet this because we don't like vegetables. |
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Diverticulosis
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- Sac-like hernias that develop with age
- Caused by increase in intracolonic pressure needed to expel feces, due to lack of fiber intake - Can progress to bleeding, sepsis, and other fun things |
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Diverticulitis
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- INFLAMMATION and DISEASE caused by the accumulation of bacteria in the diverticulosis patches in colon
- Infection - Treatment: Antibiotics, initial decrease in fiber followed by high fiber intake |
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Consequences of under/overingestion of fiber
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- Under: Diverticulosis
- Over: Constipation, problems eating (always feel full), decreased absorption of mineral cations (calcium) because fiber binds to them |
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Artificial Sweeteners
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- Much sweeter than sugar but aren't sugar
- Aren't terribly bad unless you have PKU - Pregnant women shouldn't consume anything with asparatme in it - Can cause bad side effects in some people |
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Benefits of a Low-Carb diet
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- Decrease carbs, decrease insulin/glucagon ratio, which makes glucagon increase, which promotes breakdown of fats
- Most physicians and nutritonists state that you should just decrease calories and increase exercise, doesn't matter the diet |
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Cariogenic
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Tendency of food to produce cavities
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Dental Carries
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- Fancy name for davities
- Metaboliation of simple carbs into acids by bacteria - Degrades plaque, demineralization - Sucrose is the worse |
