Vitamin and phytochemicals

Vitamins and Lecture Units 20, 21 Phytochemicals Vitamins: General Info Organic compounds      Micro nutrients need in small amounts Function as regulators allow metabolic reactions to occur Have no calories Excess may be toxic, does not enhance Classification  Water Soluble (9) – B1, B2, B3, B6, B12, folate, biotin, pantothenic acid, & C Little storage, Excess excreted in urine  Fat Soluble (4) – A D E & K Absorbed with fat  Excess may be toxic Causes of Deficiency    Little variety in diet insufficient intake Poor of vitamin Increased requirement for vitamin illness  competing drugs  growth, etc   Vitamin deficiency not big US problem Thiamin, Riboflavin & Niacin      B 1, B 2, B Function: as Deficiencies: B1-beriberi; B2-ariboflvinosis; B3-pellagra Must be added to enriched flour Source: whole grains, enriched products  Thiamin (B ) : pork  Riboflavin (B ) : milk  Niacin (B ) : protein foods Pyridoxine (B6)    Function: protein and amino acid metabolism; neural function; conversion of tryptophan to niacin Source: protein foods (meats, milk) Whole grains, fortified cold cereals Deficiency: anemia, muscle weakness Folic Acid Folacin     Functions: production of red blood cells; protein synthesis Prevents neural tube birth defects; maintains normal homocysteine level Current recommendation( µg): Women should take folic acid supplement when want to become pregnant Food sources: “foliage” vegetables, enriched bread & grain products Vitamin(B12) Cobalamin      Function: red blood cell production Nerve tissue production Deficiency: pernicious anemia; neurological disorders Source: animal products only should take supplement Absorption can be problem in elderly-take B12 shots Vitamin C - Ascorbic Acid    Functions:  Collagen formation  Antioxidant  Fights infection,  ↑ absorption of Fe Deficiency: Sources: citrus, kiwi, green peppers, cabbage family, potato Biotin & Pantothenic Acid    Functions: various metabolic reactions Biotin – glycogen, fat, protein synthesis PA – energy production No “classical” A variety of foods will provide enough Vitamin A  Retinol “pre-formed” vit A  Animal sources only   Beta carotene “precursor” changed to at absorption  Plant sources bright orange color  Anti-oxidant function  Functions of Vitamin A    Prevent night blindness Bone growth Healthy epithelial cells (not dry) skin  mucous membranes  Deficiency: xerophthalmia causes ; susceptible to infection  Vitamin A Toxicity  Concept of optimum intake Too little → deficiency  Too much → toxicity     Birth defects; liver damage; hair loss Toxic only by , not food Vit A is toxic but not carotene Vitamin A Food Sources   Precursor carotene from plants  bright orange: carrots, cantaloupe, pumpkin, sweet potato  dark green: spinach, broccoli Preformed vitamin from animals  liver - richest source  whole or fortified skim milk  egg yolk Vitamin D - Cholecalciferol      Function: ↑ blood Calcium (↑ absorption) Deficiency: Rickets in children; loss of Ca leading osteoporosis in adults Toxic in excess – Few food sources  Fortified milk, butter/margarine  Liver Sunlight activates precursor in skin Vitamin K      Function: blood “K”oagulation Synthesized by in GI tract Deficiency: abnormal blood clot;bruise easily  Hemorrhage in infants b/c little synthesis  Long term use of antibiotics Toxic only with excess synthetic supplements Food sources leafy green veg Vitamin E Tocopherol    Fertility function only in Function as anti-oxidant  Foods: protects against rancidity  Body: protects from “free radical damage” to cells and tissues; prevents artery plaque formation Food sources  Nuts, seeds, wheat germ, whole grain  Veg oil, marg, mayo & salad dressing Antioxidants      Beta-carotene Vit E Vit Selenium PUFA in our cell membranes  double bonds susceptible to oxidation  free radical + FA oxidized FA(reactive)  anti oxidants get oxidized instead Phytochemicals      Plant chemicals Not essential nutrients Rich in veg & fruits known to be protective against heart disease, cancers Most are beneficial but some are Supplements have no proof of benefit Examples of Phytochemicals       Indoles : cruciferous veggies Terpenes: orange, grapefruit Flavonoids: apple, celery, green tea Allicin: garlic, onions, leeks Phytoestrogens: soybean, soyfoods Isoprenoids: grains, fruits, veggies Genetically Modified Foods       Biologically altering food composition Enhances Improves Herbicide and insect resistance Concerns about safety of environment Controversies: unscientific and emotionally driven speculations