The Vitamins

1. The Vitamins Zeina Ghossoub El-Aswad, MSc The Vitamins

2. Vitamins • Vitamins: organic compounds that are vital to life and indispensable to bodily functions, but are needed only in minute amounts • Non caloric essential nutrients • Required in very small amounts The Vitamins

3. Vitamins • Sources • Diet • Synthesized by the body (vitamin D) • Synthesized by the bacteria in the body (vitamin K, biotin) • Efficiency of absorption depends on • Food in which they occur • Body need • Presence of other compounds in the intestine The Vitamins

4. Classification • Based on their solubility: • Fat soluble • Water soluble The Vitamins

5. The Fat-Soluble Vitamins (A,D,E,K) • Are considered as lipids (soluble in organic compounds) • Need bile, pancreatic enzymes and other fats to be absorbed • Are incorporated in chylomicrons and join the lymphatic system first • Are generally stored in the body (except vitamin K), not excreted in the urine • Often found in liver and adipose tissue The Vitamins

6. Vitamin A • Family of compounds referred to as retinoids • Functions • Role in vision: component of retina’s pigment (responsible for capturing photons) • Role in growth: necessary for the development of skeletal and soft tissues The Vitamins

7. Vitamin A • Role in maintenance or epithelia (body’s protective tissue: skin, cornea, digestive tract lining…) • Sources • Preformed vitamin: (usable form) • Only in foods of animal origin • Best are liver, fish liver oil, and milk fat (butter, cream) • Destroyed by oxidation and very high temperatures (stable in usual routine cooking methods) The Vitamins

8. Vitamin A • Carotenoids (pro-vitamin A) • E.g. beta-carotene • Can be converted to vitamin A by the body • Are pigments found in orange-red vegetables and fruits (carrots, peaches, apricots, mangos,…) and dark green leafy vegetables (spinach, broccoli). Amounts decrease upon dehydration. • Not toxic in large amounts • Antioxidant activity: protect from reactive oxygen-containing free-radicals The Vitamins

9. Vitamin A • Deficiency: • Eye and vision troubles: night blindness, inability to adapt from bright light to darkness • Xerophthalmia (dry eye), corneal deterioration that leads to irreversible blindness The Vitamins

10. Vitamin D • Functions as a hormone • Main function is maintaining blood calcium levels and bone and teeth integrity • Maintains calcium levels for other cellular functions (utilizing bone as the major storage of calcium in the body) The Vitamins

11. Vitamin D • Sources • Major part: synthesized by the body from cholesterol • Food sources: variable amounts in natural foods (richest are fatty fish: salmon, sardines) • Best dietary sources are “vitamin-D fortified” foods (milk, cereals) • Ergosterol can be transformed to pro-vitamin D to vitamin D The Vitamins

12. Vitamin D • Deficiencies: deficient calcium deposit which leads to bone malformation or deterioration • In children: vitamin D deficiency disease causes rickets • Short bones that cannot withstand stresses (bowed legs) The Vitamins

13. Vitamin D • Deficiency in adults: • Osteomalacia: causes bending of the spine and bowing of the legs • Osteoporosis:symptoms similar to osteomalacia, but more factors involved (decreased estrogens, lack of exercise, smoking, age…) • Toxicity: excessive calcification even in soft tissues (kidneys with stones…) The Vitamins

14. Vitamin E • Primary function as an antioxidant • Collects and neutralizes O-containing free radicals that can oxidize and thus damage cell components, in particular membrane PUFA’s The Vitamins

15. Vitamin E • Sources: widely available in plant and animal food • Best sources are plant seed oil (soybean, sunflower…). Amounts decrease as oil ages The Vitamins

16. Vitamin E • Classic signs and symptoms of deficiency include • Anemia due to erythrocyte (red blood cell) hemolysis • Loss of muscle coordination and reflexes • Impaired movement, vision and speech The Vitamins

17. Vitamin K • Main function is to help the blood clot • Sources: best food sources are green leafy vegetables • Can be obtained from a non food source- the intestinal bacteria The Vitamins

18. Vitamin K • Deficiency: • Common causes: destruction of intestinal bacteria by continued antibiotic treatment • In newborn infants that fail to establish intestinal bacteria that produce vitamin K leads to hemorrhage The Vitamins

19. The Water Soluble Vitamins • The B and C vitamins • Absorbed easily directly into the blood and easily secreted • Vitamin B12 needs to combine with an “intrinsic factor” (made by the stomach) to be absorbed The Vitamins

20. The Water Soluble Vitamins • Are not stored in the body (except B12) • First deficiency symptoms occur within few days after inadequate intake • Help enzymes in their function The Vitamins

21. The B Vitamins and Their Relatives • B vitamins involved in energy production (ATP) reactions • Thiamine (B1) • Deficiency: beriberi: nervous and cardiovascular problems • Niacin (B3) • Deficiency: pellagra: the “3 D’s” disease (dermatitis, dementia, diarrhea) • Riboflavin (B2) • Pantothenic acid The Vitamins

22. The B Vitamins • Vitamins involved in CHO, lipid and protein metabolism: • Pyridoxine (B6) • Biotin The Vitamins

23. The B Vitamins • Vitamins involved in nucleic acid synthesis: • Folate • Cobalamine (B12) • Deficiency: influences cell proliferation which leads to poor growth, anemia, intestinal disorders The Vitamins

24. The B Vitamins • Sources: • Common food sources: meat (especially liver) and poultry, yeast, bran and germ of cereal grain, eggs • Biotin: significant amounts produced by intestinal bacteria • Cobalamine: found only in animal foods. Strict vegetarians need supplements • Stability: excess heat and alkali (e.g.: soaking peas and beans in water and soda) destroy some B vitamins The Vitamins

25. Vitamin C • Promotes the immune response to infections • Stimulates iron absorption • Involved in collagen synthesis: a protein substance that forms the base for all connective tissues in the body. Important for fracture/wound healing The Vitamins

26. Vitamin C • Sources: fresh fruits and vegetables (esp. if acidic). Content decreases during storage, esp. if peeled, cut… • Processed and cooked foods are poor resources • Easily destroyed by heat and upon exposure to air (oxidation) • Stable in acidic environments The Vitamins

27. Vitamin C • Deficiency causes scurvy, and symptoms include: • Swollen and inflamed gums, loose teeth • Dryness of eyes and mouth • Dry itchy skin, hair loss • Defect in wound healing • Frequent infections The Vitamins

28. Vitamin Supplements • Needed/recommended: • Nutrient deficiencies • Pregnancy and lactation (folate, iron) • Newborn infants (K) • Frequent diets • Elderly • AIDS and other wasting illnesses The Vitamins

29. Vitamin Supplements • Drug/alcohol abuse • Recovery from surgery, injury or illness • Strict vegetarians (B12) The Vitamins

30. Vitamin Supplements • Conditions where they may be risky/useless • To feel secure about getting one’s needs • Conditions that increase vitamin toxicity (kidney or liver disease) • To get energy when feeling tired • To cope with stress • To build muscles faster • To prevent/cure self-diagnosed conditions The Vitamins