Nutritional Sciences 1034 Exam 2 Notes

Dietary Reference Intakes (DRI) 09:00:00

19/09/2007

Ch2 DRIs • • • • • • • • •

Replace and expand on the Recommended Dietary Aowance Intended to prevent nutritional deficiencies as well as reduce the risk of chronic diseases Specific for gender, age (infants to 70+ years), and pregnancy/lactation Consists of several types of reference intakes RDA – Recommended Dietary Allowance AI – Adequate Intake UL – Tolerable Upper Intake Level EER – Estimated Energy Requirement DV – Daily Value, for food labels (Not the same as the rest, RDA for worst case scenerio)

RDA •

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Average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97 – 98 percent) healthy individuals in a particular life stage and gender group o Not the minimum requrement o You can be below RDA and not have deficiency Developed to prevent nutrient deficiency diseases Age and gender specific Deficiency: intakes below 70% of RDA over and extended period o 2/3 of RDA is ok for a few days

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Toxicity: intakes above 3 times RDA Adequate Intake (AI) • Recommended intake value based on observed or experimentally determined approximations or estimates of nutrient intake by a group of healthy people • Used when an RDA cannot be determined o Not as definitive as RDA; more research needed Tolerable Upper Intake Level (UL) • The highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects increases. o Adverse effects over a long time of eating bad Estimated Energy Requirement (EER) • An estimate of the calorie needs of the average person based on gender, age, height, weight, and physical activity level o Energy = calories Range of Intake • Upper Level (UL) met or exceeded • RDA/AI/EER (good) • Deficient State Daily Value (DV) • Used on food labels (%DV) • Based on 2,000 kcal diet • Rough guide for comparing food nutrient content to requirements

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Vitamins: Fat Soluble (A, D, E, K) 09:00:00

19/09/2007

What are Vitamins? • Essential organic compounds o Essential – important to proper growth o Organic - carbon • Needed in very small amounts • Do not provide energy • Function as coenzymes: B vitamins and vitamin K o Work with enzymes • Fat soluble: vitamins A, D, E, and K o Soluble in non polar things • Water soluble: B vitamins and vitamin C o Soluble in polar things Why are they essential? • Vitamins either cannot be synthesized in the body or are not synthesized in adequate amounts o We are one of the few animals that do not make vitamin C o We didn’t make some vitamins we needed as infants • Must be supplied in the diet • Exceptions: vitamins D, K, niacin, and biotin • Produce deficiency symptoms when missing from the diet Function of vitamins • Participate in energy-yielding reactions

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Contribute to blood formation, clotting, bone health, protein metabolism, antioxidant defense Sources and storage • Plant and animal foods in diet • Supplements • Fat-soluble vitamins (except vitamin K) are stored in body – not readily excreted o Hard to get deficiency • Water-soluble vitamins (except vitamins B6 and B12) are not stored – readily excreted via urine Deficiency and toxicity • Deficiency: vitamin is lacking in the diet and the body stores are

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depleted, loss of function o Not often seen in our country Toxicity: excessive intake can cause damage to the body o Upper limit – line at where toxicity begins

Toxicity • Fat-soluble vitamins accumulate in the body most readily and can cause toxic effects (3x RDA for vitamin A-most extreme and easy to overtake) • Water-soluble vitamins are toxic only in very large amounts (15100x RDA) • Toxicity most likely from supplementation Preservation of vitamins • Eat foods soon after harvesting • Tore properly (avoid heat, light, air) o Cold/dark • Avoid excessive cooking

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o Boiling in water causes vitamins to go into water • Frozen frouts and vegetables are as nutritious as fresh Absorption of fat-soluble vitamins (A, D, E, K) • Absorbed along with dietary fat o Some drugs block absorption • Transported with fat through the bloodstream inside lipoproteins • Usually 40-90% of fat-soluble vitamins are absorbed • Fat malabsorption (diseases or weight loss during orlistat) may cause deficiency Vitamin A • Found in several forms of foods o carrots • •

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Retinoids in foods of animal origin Carotenoids (pigments) in vegetables, can be converted into vitamin A o Pre- or pro- vitamin A Vitamin A Functions o Promotes vision  Night blindness o Promote growth, development, reproduction o Prevents drying of the skin and eyes  Xerophthalmia (dry eye)  Need to maintain skin

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Promotes immune function and infection resistance Cardiovascular disease prevention Cancer prevention Acne medication (vitamin a derivatives) Vitamin A recommendations o Measured in Retinol Activity Equivalents (RAE) = vitamin A + carotenoids (beta-carotene) o RDA is 900 ug RAE for men, 700 ug RAE for women o DV is 1000 ug RAE o Average intakes in the us meet the RDA o Much of vitamin A is stored in the liver o o o o

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Vitamin A Deficiency o Leading cause of preventable blindness in children o Night blindness o Xerophthalmia o Dry skin o Poor growth Vitamin A Toxicity o Highly toxic o Enlarged liver o Fetal malformations and spontaneous abortions (why Accutane is not prescribed during pregnancy) o Bone/muscle pain, fractures

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Headaches Hair loss Skin changes Eating polar bear liver – toxicity, makes person blind. Vitamin A sources o Yellow-orange vegetables (beta-carotene), dark green leafy vegetables (lutein and zeaxanthin) and tomatoes (lycopene) o Liver o Fish oils o Eggs o Fortified milk and yogurt o o o o

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Vitamin • • • • • •

D Prohormone: activated by enzymes in the liver and kidneys Derived from cholesterol (like a hormone Synthesized from sunlight 80-100% of vitamin D needs can be provided by sunlight Deficiency causes bone diseases Functions o Calcium metabolism and bone health o Regulates absorption of calcium and phosperos from intake o Regulates deposition of cacium in bones o Influences cell development

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o Immune function and cancer prevention o Immune system modulator Reccomendations o 5 ug/day for adults under 51 o Sun Deficiency o Rickets, deficiency in children  Bowed legs  Rib “beads” at sternum  Slow growth  Bowed spine o Osteonalacia – deficiency in adults “soft bones” bones lose minerals and become pourous

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Toxicity o Toxic in high amounts, especially for infants and children o Over-absorption of calcium, calcium deposits in organs o Weakness, appetite loss, diahrea, vomiting, mental confustion, increased urine Sources o Fortified milk/milk products o Fortified breakfast cereals

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o o o o Vitamin • • • • • •

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Fish oils Sardines Salmon Sunlight

E The fat soluble antioxidant vitamin Protects unsaturated fats from oxidization Donates electron to electron seeking compounds, “free radicals” Found mostly in cell membranes Improves vitamin A absorption Recommendations o 15 mg/day for adults o many adults get recommended Deficiency and toxicity o Deficiency  Breakdown of cell membranes  Hemolytic anemia  Nerve degeneration o Toxicity (not likely)  Muscle weakness  Headaches

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Nausea Inhibition of vitamin K metabolism

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Sources o Plant oils and products made from plant oils o Green leafy vegetables o Some fruits o Nuts and seeds o Fortified breakfast foods Vitamin K • Supplied by diet as well as intestinal bacteria • Synthesized by bacteria in the colon, 10% of Vitamin K needs • Functions o Coenzyme with major role in coagulation process (blood clotting) o Activates proteins invoved in bone metabolism • Deficiency o Hemorrhage o Fractures o Most at risk: patient with long standing fat malabsorption, person taking antibiotics fro long periods, infants • Toxicity o Unknown • Sources o Green leafy vegetables o Liver o Broccoli o Peas o Green beans o Fresh oils o Meats

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Water Soluble Vitamins

19/09/2007 09:00:00

Water-Soluble Vitamins

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Dissolve in water Very little is stored in body Excreted from body if consumed in excessive amounts Include all essential B vitamins, Vitamin C, and choline (vitamin-like compund) • Large amounts can be lost during cooking B Vitamin Functions • Coenzymes in energy metabolism o Pathways used by carbohydrates (CHO), amino acids, and fats • Red Blood Cell formation and functions • Neurological function • Nearly 50-100% of B vitamins in the diet are absorbed Thiamin (B1) • Coenzyme form used in CHO metabolsm • Nerve function • RDA o 1.1 to 1.2 mg/day o most diets exceed RDA •

Thiamin Deficiecy and Toxicity o Deficiency  Beriberi

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 Sinhalese: “I cannot, I cannot”  Dry: wasting, peralisys  Wet: edema, heart failure  Seen in areas where white rice is a staple o Non-Toxic Thiamin Sources o Lean pork products o Organ meats o Whole and enriched grain products o Dried beans o Seeds o Peanuts o Peas

Riboflavin • Coenzyme form participate in energy-yielding metabolic pathways (aerobic energy) • RDA o 1.1 to 1.3 mg/day o nutrient-poor diets are usually low in riboflavin, i.e. alcoholics • Riboflavin deficiency and toxicity o Deficiency  Cheilosis (cracking on outside of lips), angular stomaitis (cracks or sores at corners of mouth, inflimation of mouth and tounge, and dermatitis)

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Niacin • •

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o Non-toxic Sources o Milk and milk products  Destroyed by light o Enriched and whole grains o Meat, liver, eggs, spinach, oysters Coenzyme forms in energy metabolism RDA o 14 mg/day for women o 16 mg/day for men Deficiency and Toxicity o Deficiency  Pellagra – 4 D’s  Dermatitis  Diarriha  Dementia  Death o Toxicity with intakes >100 mg/day  Vasodilation, itching, headaches, flushing Sources

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Poultry, beef, tuna, and other fish (high protein foods) Enrichd prducts Wheat bran Asparagus Peanuts Can be synthesized from tryptophan (essential amino acid)

Vitamin B6 • Coenzyme form o Activates enzymes needed for metabolism of CHO, fat, and protein o Synthesizes non-essential amino acids o Synthesizes neurotransmitters o Synthesizes hemoglobin & WBC o Role in homocysteine metabolism o PROTIEN METABOLISM •

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RDA o Avg daily intake is more than RDA o Alcoholics at risk for deficiency B6 Deficiency and Toxicity o Deficiency  Irritability, nervousness, depression/moodiness, vomiting, skin disorders, and impaired immune response o Toxicity >200 mg/day can lead to irreversible nerve damage

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Folate • • •

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Risk with using megadoses to reduce the symptoms of PMS

Sources o Animal products o Dairy products o Bananas o Potatoes o Widely available Coenzymes help form DNA and metabolize various amino acids Red blood cell formation and maturation RDA o 400 ug/day adults o 600 ug/day pregnant women Deficiency and Toxicity o Deficiency  Results in neural tube defects in fetus  Results in megaloblastic anemia in adults (large immature RBC in the blood, fewer mature RBC, decreased ability to carry O2) o Toxicity  Excess can mask B12 deficiency Sources o Foliage

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Liver OJ Enriched products Grains, legumes  Heat and microwave can destroy some forms

Vitamin • • •

B12 Coenzyme form Role in folate metabolism Maintaining myelin sheaths o Transfer electrical pulse • RBC formation • RDA o 2.4 mg/day for adults o stored in liver •

Absorption o Requires a protein from salivary gland o Requires stomach acid o Requires intrinsic factor  Protein-like compund produced by the stomach that enables B12 absorption o Absorbed in the last part of small intestine  About 50% absorbed

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Deficiency and Toxicity o Deficiency  Pernicious anemia: (“deadly, fatal”) duue to lack of intrinsic factor  inability to absorb B12  Megaloblastic anemia  Nerve degerneration & peralysis o Non-toxic Sources o ONLY in foods from ANIMAL SOURCES o Animal products o Organ meats o Seafood o Eggs, milk o Hot dogs o Synthesized by bacteria, fungi, and lower organism

Pantothenic Acid • Coenzyme form essential for metabolism of CHO, fat, and protein • RDA o 5 mg/day • Deficiency o Rare, however usually in combination with other deficiencies • Toxicity unknown

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Biotin • • • •

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Sources o Found everywhere o Wheat, milk, veggies, sunflower seeds, mushrooms, peanuts, eggs Coenzyme form aids in fat and CHO metabolism Helps break down certain amino acids RDA o 30 ug/day Deficiency o Rare. Scaly/inflamed skin, changes in tounge and lips, decreased appetite, nausea/vomiting Non-toxic Sources o Caluflower o Egg yolk o Peanuts, cheese o Intestinal bacteria can synthesize and supply some biotin o More than a dozen raw egg whites a day can cause absorption to be inhibited C Synthesis of callogen o Makes up connective tissue Iron absorption

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Choline • • •

Immune function Antioxitant RDA o More for smokers Deficiency of Vitamin C o Scurvy: bleeding gums, pin-point hemorrhaging, poor wound healing, wakness Toxicity o Stomach inflammation and diarrhea Sources o Citrus fruits o Potatoes o Green peppers o Cauliflower o Broccoli o Strawberries o Lettuce o spinach 8-3 Essential nutrient, however it is not considered a vitamin All tissues contain choline Precursor for acetylcholine (neurotransmitter)

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• • Choline • •

Choline • • • • • •

Precursor for phospholipids o Good for tying things together RDA o 425-550 mg/day for adults Deficiency (never the right answer) Deficiency o Rare Toxicity o In high doses: associated with fishy body odor, vomiting, salivation, sweating, hypotension, GI effects Sources Widely distributed in foods Milk Liver Eggs Peanuts Lecithin added to foods

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Major/Macro Minerals

19/09/2007 09:00:00

Minerals • Various functions in the body • Do not provide energy • Major/macro minerals • Micro/trace minerals • Bioavailability depends on interactions with fiber, vitamins, and other minerals o Sometimes 10% absorbed o Fiber keeps some from being absorbed o Compete for absorption • Toxic in excessive amounts, especially trace minerals Major/Macro Minerals • Calcium (Ca) • Magnesium (Mg) • Sodium (Na) • Sodium (Na) • Chloride (Cl) • Potassium (K) • Phosphorus (P) • Sulfur (S) Calcium • 99% in bones and teeth

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makes up 40% of all the minerals present in the body Functions o Forming and maintaining bones o Blood, nerve, muscles, and cells RDA o 1000 to 1200 mg/day for adults o 1300 mg/day for children o Avg intake is NOT enough Absorption of calcium o Normally 25% absorbed from food o Vitamin D and acidic gut help absorption o Absorbed in upper part of small intestine o Absorption increased to 60% in time of need, i.e. pregnancy, infancy Decreased Absorption of Calcium o High fiber intake o Excess phosphorus  soda o Vitamin D deficiency o Polyphenols (tannins) in tea o Diarrhea o Aging

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Calcium Deficiency o Deficiency  Osteoporosis: loss of bone mass  Most at risk • Post-menopausal women • Slender, inactive women who smoke  Previntion • Build peak bone mass when young with adequate calcium and vitamin D intake • Weight-bearing physical activity o Calcium Toxicity  Not common  Risk of kidney stones and other problems o Sources  Dairy products  Canned fish  Ca-fortified orange juice  Supplements

Magnesium • 60% is found/stored in the bones • Functions o Bone formation

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o Enzyme function o Nerve and heart function RDA o 310-320 mg/day for women o 400 to 420 mg/day for men Deficiency o Unlikely unless diurectic use or alcoholism o Weakness, muscle pain, poor heart function Toxicity o Overuse of antacids, laxatives, or supplements o Causes diarrhea and weakness in patients with kidney failure Sources o Whole grains o Nuts, beans, green vegetables

Sodium • Major positive ion in extracellular fluid • Blood Na levels controlled by the kidneys • Functions o Water balance o Nerve and muscle function

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RDA o 1500 mg/day age 19-50 o 1300 mg/day age 51-70 o 1200 mg/day age 71 years and older Deficiency o Hyponatremia  Rare, only with persistent vomiting, diarrhea, or excessive perspiration (losing 2-3% body weightmarathon runners)  Muscle cramps, nausea, vomiting, dizziness, shock, coma Toxicity o Contributes to hypertension in susceptible  Increases Ca loss in the urine Sodium Sources o Table salt (40% Na) o Processed foods o Condiments o Chips o Added to flavor foods

Chloride • Major negative ion for extracellular fluid • Functions o Hydrochloric acid in stomach

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o Nerve function o Water balance RDA o 2300 mg/day Deficiency o Rare, convulsions in infants Toxicity o Unlikely, linked to hypertension in susceptible people when combined with Na Sources o Table salt (60% Cl) o Some vegetables o Processed foods

Potassium • Major positive ion in intracellular fluid • Functions o Water balance o Nerve and muscle function • RDA o 4700 mg/day • Deficiency

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o Rare, only with persistent vomiting or prolonged diuretic usage o Irregular heart beat, muscle cramps Toxicity o Unlikely, seen only in kidney failure Sources o Fruits, vegetables, milk, grains, meats, dried beans o Bananas o Orange juice

Phosphorus • Major negative ion of intracellular fluid • Bone and tooth component • Component of cell membranes, DNA • Acid/base balance • RDA o 700 mg/day for adults o 1250 mg/day for children o Average intake exceeds RDA • •

Deficiency o Unlikely, possible bone loss Toxicity

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Sulfur • •

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o Impairs bone health in people with kidney failure or low Ca intake Sources o Wide variety of foods o Dairy products o Breads and cereals o Meats and fish o Soft drinks

Dietary proteins supply all we need Functions o Part of amino acids and vitamins o Drug detoxification No deficiency if protein is adequate No toxicity Sources o Protein foods

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Minerals: Micro/Trace

19/09/2007 09:00:00

Micro/Trace Minerals • Needed in much smaller amounts than macro minerals • Essential for health • Difficult to study o Only trace amounts in the body • Animal sources of mineral are generally better absorbed Minerals • Iron (Fe) • Iodine (I) • Zinc (Zn) • Copper (Cu) • Chromium (Cr) • Fluoride (F) • Selenium (Se) Iron • •

~ 18% is absorbed, determined by body’s need Heme iron vs. nonheme iron (heme as in hemoglobin which iron is part of) o Heme iron found in animal products, better absorbed that nonheme iron  No hemoglobin in plants  Redder the better

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o Meat protein factor my aid in nonheme absorption Vitamin C enhances absorption of nonheme iron Functions o Component of hemoglobin in RBC transport of oxygen and carbon dioxide o Energy metabolism o Immune function  Need iron to fight off disease o Cognitive development (brain) RDA o 8 mg/day men o 18 mg/day women o Average intakes for men exceed the recommendation, most women’s intakes are low Deficiency o Microcytic hypochromic anemia, low levels of hemoglobin and hematocrit, insufficient intake and stores o At risk: infants, toddlers, chronic blood loss, vgans, runners, and women of childbearing years o Signs: paleness, brittle nails, fatigue, poor temperature control, poor growth Toxicity o Fairly rare (1/250 have both hemochromatosis genes) o Liver and heart damage (extreme cases of Fe overload) o GI upset with Fe supplements o Infants/children at risk of Fe poisoning

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Iodine • •

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Iron o o o o o

 Vitamins and mineral supplements can poison children Sources Med (redder the better) Seafood Broccoli Peas Whole and enriched grains

70-80% of Iodine in the body is found in the thyroid gland Functions o Supports thyroid hormone synthesis o Regulates metabolic rate, growth, and development RDA o 150 ug/day Deficiency o Goiter: thyroid gland enlarges  Mountainous areas o Cretinism: stunting of fetal growth and mental development as a result of low iodine in maternal diet Toxicity o Thyroid hormone synthesis is inhibited o Looks like iodine deficiency, swelling of thyroid gland

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o Consumption of seaweed poses risk Sources o Iodized salt o White bread o Saltwater fish o Dairy products

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Involved in many areas of metabolism 40% of Zn in absorbed, competes with copper and iron for absorption Functions o Required for nearly 200 enzymes o Normal growth and sexual development o Immune function o Protein and nucleic acid metabolism o Wound healing RDA o 8mg/day for women o 11 mg/day for men Deficiency o Dwarfism  Groth retardation and poor sexual development

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 Decreased appetite and taste sensation  Poor wound healing Toxicity  Excessive intakes reduce copper absorption  Diarrhea  Depressed immune function Sources Seafood Meats milk legumes

Zinc o o o o o Whole grains

Copper • Function o Aids in Fe metabolism o Hemoglobin formation and Fe transport o Elastin and collagen synthesis  Proteins that hold everything together o Antioxidant enzymes o Immune function • RDA

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o 900 ug/day Deficiency and Toxicity o Deficiency  Anemia  Low WBC count  Poor growth  Bone loss  Some forms of cardiovascular disease o Toxicity  Vomiting  Wilson’s Disease: A genetic deficit that causes an

accumulation of Cu in the brain or liver  brain damage, liver failure, death • Copper sources o Organ meats o Whole grains o Legumes o Nuts Chromium • Recently discovered essential trace element (1959) • Functions o Maintenance of glucose uptake into cells o Aiding insulin function

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RDA o 25 to 35 ug/day Chromium Deficiency and Toxicity o Deficiency  Impaired glucose control  Diabetes like symptoms  Elevated blood cholesterol and triglycerides o Toxicity  Caused by industrial contamination, not by food sources  Liver damage and lung cancer Chromium Sources o Egg yolks o Whole grains o Pork o Nuts o Mushrooms o Beer

Fluoride • Functions o Strengthens tooth enamel o Decreases the risk of dental caries

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o Inhibits tooth demineralization and enhances tooth remineralization RDA o 3.1 mg/day for women o 3.8 mg/day for men Fluoride Deficiency and Toxicity o Deficiency  Increased risk for dental caries o Toxicity  Fluorosis: mottling (staining) of teeth during tooth development  

Bone pain Stomach upset

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Sources o Fluoridated water o Toothpaste o Tea Selenium • Functions o Antioxidant enzymes (glutathione peroxidase) o May help prevent cancer • RDA o 55 ug/day • Selenium Deficiency and Toxicity o Deficiency  Muscle pain and weakness  In China a while back  Form of heart disease o Toxicity  Hair loss, nausea/vomiting, weakness, rashes, cirrhosis of the liver • Selenium Sources o Meats o Eggs o Fish o Seafood 37

Review

19/09/2007 09:00:00

Functions of B-Vitamins

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Fat, CHO, and Energy metabolism o Thiamin o Riboflavin o Niacin o Pantothenic Acid o Biotin

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Protein and Amino Acid Metabolism o Vitamin B6 Red Blood Cell formation o Folate, o Vitamin B12 (& Vitamin B6)

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Functional Roles • Coenzymes o B-Vitamins o Vitamin K • Antioxidants o Vitamin E o Vitamin C o Selenium • Bone Health

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Vitamin D Vitamin K Calcium Phosphorus Magnesium • Red Blood Cells o Folate o Vitamin B12 o Iron o Copper (& Vitamin B6) Water Balance Minerals • H2O Balance o Sodium (Na), Potassium (K), Chloride (Cl), Phosphorus (P) as Phosphates • Extracellular: Na (+) Cl (-) (Salt) • Intracellular: K (+) P(-) Notable Deficiencies • Xerophthalmia o Vitamin A • Rickets o Vitamin D • Beriberi o o o o o

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o Thiamin Cheilosis o Riboflavin Pellagra o Niacin Scurvy o Vitamin C Goiter o Iodine Dwarfism o Zinc Night Blindness o Vitamin A Osteomalacia o Vitamin D Neural tube defect o Folate Osteoporosis o Calcium Weakness, muscle pain o Magnesium

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Creinism o Iodine • High Blood Glucose o Chromium • Dental Caries o Fluoride Deficiency Anemias • Megaloblastic Anemia o Folate • Pernicious Anemia o Vitamin B12 • Microcytic, Hypochromic Anemia o Iron (Copper) Deficiency and Toxicity • Most likely to be deficient in US diet o Vitamins  Vitamin E  Folate o Minerals  Calcium, Iron • High potential for toxicity

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o Vitamins  Vitamin A o Minerals  Iron  Chromium Enriched/Fortified Foods • Flour and other refined grains o Thiamin o Riboflavin o Niacin o Folate o Iron •

Milk and dairy products o Vitamin A o Vitamin D

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Salt o Iodine Water and toothpaste o flouride

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