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Vitamins

Vitamins. Chapter 7. Learning Objectives. Explain the roles vitamins play in growth and good health List and describe the general functions and food sources of fat-soluble vitamins and water-soluble vitamins

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Vitamins

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  1. Vitamins Chapter 7

  2. Learning Objectives • Explain the roles vitamins play in growth and good health • List and describe the general functions and food sources of fat-soluble vitamins and water-soluble vitamins • List nutrients of concern that many Americans lack in their diets and foods sources of these nutrients

  3. Learning Objectives • Identify diseases caused by specific vitamin deficiencies • Give tips to ensure that vitamin intake is sufficient • Identify cooking techniques that promote retention of nutrients and those that cause nutrient loss from foods

  4. Vitamins • Essential for life and health • Needs are small • measured in milligrams (1/1000 of a gram) or micrograms (1/1000 of a milligram) • Do not provide energy • Must be obtained through food

  5. Vitamins • All are organic compounds (contain carbon in their structure) • Each vitamin has specific biological functions • Absence of each vitamin causes a specific deficiency disease

  6. Vitamins 13 are essential nutrients • Must come from food, not made in the body or the body does not make enough • Some foods contain precursors that can be converted in the body into vitamins

  7. How the Body Uses Vitamins • Facilitate the processes by which other nutrients are: • Digested • Absorbed • Metabolized • Built into body structures • Absence of a vitamin may cause a nutrient deficiency (symptoms go away when vitamins are replenished through diet)

  8. Dangers of Excess Vitamins Regular intake of high-dose supplements can be dangerous, stressing liver and kidney • Amounts found in foods are safe Fat-soluble vitamins are stored, toxicity possible Supplements can interfere with meds/ alter lab tests

  9. Two Types of Vitamins 1.) Fat Soluble A, D, E, K 2.) Water Soluble B vitamins -thiamin, riboflavin, niacin, folate, B12, B6, Biotin, Pantothenic Acid Vitamin C

  10. Shortfall Nutrients – or Nutrients of ConcernMany people do not get adequate amounts of: Vitamins Minerals • Vitamin A • Vitamin C • Vitamin D* • Vitamin E • Vitamin K • Calcium* • Magnesium • Potassium * • Sodium* * Biggest nutrient gaps Most diets also lacking dietary fiber Most children and adults get too much sodium

  11. Fat soluble vitamins

  12. Fat Soluble Vitamins • Must be absorbed with fat • Stored in body fat and liver • Can build up to toxic levels, especially as supplements in high doses • Vitamins A, D, E, K

  13. Vitamin A Antioxidant Important roles in: Vision Bone and tooth growth Reproduction Cell functions Immune system

  14. Vitamin A • Retinol – active form • liver, egg yolks, dairy foods • Precursors include carotenoids – beta-carotene which can be changed to active form in intestine • bright orange, yellow, green fruits and vegetables • Measured in retinol activity equivalents (RE) • it takes 12 mcg of beta-carotene to convert to 1 mcg retinol

  15. Vitamin D Some made in body with sunlight • Those who do not have skin exposed to sunlight need more from diet Acts like a hormone to help body absorb and regulate calcium and phosphorus for strong bones, teeth and muscle Several forms: • Calciferol • D2 = ergocalciferol • D3 = cholecalciferol

  16. Vitamin D Food sources dairy and other fortified foods, egg yolks butter, salmon, shrimp, mushrooms 100 IU in 1 cup milk Deficiency • fragile bones (osteoporosis) • soft bones (osteomalacia), • rickets • increased cancer risk • depression, dementia • infections, gum disease

  17. Vitamin D Requirements • Dietary Guidelines 2010 • 600 IU children, most adults • 800 IU 70 and older • 1000 IU common supplementation recommendation • Up to 10,000 IU recommended to replenish for 1-2 weeks, then 1000 IU a day

  18. Vitamin E - Tocopherol Antioxidant in cell membranes • especially lungs, brain, blood Sources Seeds, nuts, oils fortified cereals, spinach greens, pumpkin, red bell peppers

  19. Vitamin K - Phylloquinone • Intestines make about half of daily need • Antibiotics reduce production • Needed to make the proteins involved in blood clotting • People who take meds to reduce blood clotting may need to adjust intake of foods with vitamin K • Works with vitamin D to regulate blood calcium levels and form bone • Food sources: green leafy veg (kale, greens, spinach, broccoli)

  20. Water soluble vitamins

  21. Water Soluble Vitamins • Should be eaten daily • None or little stored • Excesses usually excreted through urine • Excess by supplements can cause increased need

  22. The B Vitamins

  23. B Vitamins- General Functions Metabolize Energy as Coenzymes(catalysts) • release calories from carbohydrates, protein and fats Necessary to form red blood cells, heal wounds Growth and development Nerve functions Proper digestion and appetite

  24. B Vitamins Continued.. • B vitamins found in most protein foods, leafy green vegetables and grain (enriched) products Enrichment- replaces thiamin, riboflavin, niacin • Generally little stored in the body • Oversupply or deficiency of one B vitamin can effect need and use of others

  25. Thiamin- B1 • Critical role in energy metabolism • Necessary for nerve and heart function

  26. Riboflavin- B2 • Essential for metabolism of carbohydrates to produce energy • Milk, dairy and organ meats are rich in riboflavin. • Light destroys riboflavin. Dairy should be in containers that block light

  27. Niacin- B3 • Essential for metabolism of carbohydrates to produce energy • Body can make niacin by converting tryptophan (essential amino acid) • Niacin- high doses can cause itching, flushing, liver damage, high blood sugar

  28. Pantothenic Acid- B5 • Coenzyme in metabolic processes • Deficiencies Uncommon • No toxicities reported

  29. Pyridoxine- B6 • Part of coenzyme necessary for metabolism of carbohydrates, fat and protein • Necessary for nervous and immune system • Needed to convert tryptophan to niacin • Needed to make hemoglobin

  30. Vitamin B12 • Assists in bone-blood cell formation • Pernicious anemia • Protects nerve fibers • Carbohydrate, protein, fat energy metabolism • Needs intrinsic factor for absorption • Found in animal foods, fortified in vegetarian. • Vegans should B12 supplement

  31. Folate • Part of coenzymes necessary to form DNA • Important for red blood cell formation • Helps the body use protein

  32. Folate • Food Sources: legumes, oranges, green leafy vegetables, enriched grains, asparagus, beets • Some lost in cooking • Fortification- adds folacin to grain foods. • Folacin- more stable form Critical in early pregnancy to prevent birth defects • Part of coenzymes necessary to form DNA • Women of child bearing age need supplemented folate

  33. Vitamin C – Functions • Helps make collagen (protein that stabilizes cell walls) • Helps keep gums and other tissues healthy • Aids in the healing of cuts and wounds • Helps the body absorb iron • Necessary to form thyroxin (hormone that regulates metabolic rate)

  34. Vitamin C Shortfall nutrient because many Americans do not eat enough fruits and vegetables • More needed by: • Pregnant and lactating women • Smokers • Infections, fevers or wound healing

  35. Food Issues Related to Vitamin C • Least stable nutrient. Destroyed by: • Heat • Leaching into water while cooking • Evaporation • Some juices and cereals fortified with Vitamin C • Supplements in high doses may cause gastrointestinal symptoms

  36. Vitamin C - Sources Excellent sources include: • Red bell peppers • Oranges • Grapefruit • Broccoli • Strawberries • Papaya • Brussels sprouts • Fortified cereal or juices • Tomatoes

  37. Bioavailability is Influenced By: • Nutritional status - if you are deficient your body will absorb more • Other nutrients at the same meal- compete for protein carriers needed for absorption • Nutrients in high dose supplements are not used as well as nutrients in foods • Binders such as oxylates and phytates

  38. Nutrient Bioavailability Enhanced By: The form of a nutrient; • vitamin D3 is absorbed better than D2 Fermentation processes • Ex. miso and tempeh, may improve iron bioavailability Food preparation techniques • soaking and sprouting beans, grains and seeds, leavening bread, can reduce binding of zinc by phytic acid and increase zinc bioavailability Organic acids • Ex. citric acid can enhance zinc absorption

  39. Nutrient Bioavailability is Reduced By: • Too much of one mineral can reduce the absorption of another • Polyphenols in regular and herbal teas, coffee and red wine bind some iron • Cooking softens cell walls of food so more nutrients released

  40. Nutrient Retention – Purchase Forms • Canned: Canned foods are packed at their peak of freshness and due to the absence of oxygen during their storage period, canned fruits and vegetables have a longer shelf life and remain relatively stable up until opened. • Fresh: Fresh is best if consumed within a short time after purchasing. • Frozen: Frozen products are packed at their peak of nutrition and freshness. At least equal to fresh in nutrients.

  41. Nutrient Retention – In the Kitchen • To retain nutrients: keep fresh produce chilled and covered • Peel only when necessary. Peeling removes nutrients and fiber of peel and under peel • Use pulp in citrus rather than straining it out • Purees and coulis increase nutrient availability by breaking cell walls • Serve cooked vegetables immediately after cooking – holding causes nutrient losses

  42. Nutrient Retention – In the Kitchen • Reserve liquids from cooked vegetables and add to stocks, sauces, etc • Fry as little as possible. High heat destroys some nutrients and creates free-radicals • Drain and rinse canned beans to reduce sodium • Drain brines from capers, pickles and other foods packed in salted liquids

  43. Chapter 7: Vitamins, Minerals and Phytochemicals • Discussion • Questions and Answers • Assignments

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