1. Vitamins: Vital Keys to Health BIOL 103, Chapter 9

2. Today’s Topics Understanding Vitamins Fat Soluble Vitamins: A, D, E, K, and Carotenoids The Water-Soluble Vitamins: Eight Bs and a C Bogus Vitamins

3. Understanding Vitamins Vitamins – Needed in small amounts – Not an energy source – Individual units – Organic compounds essential for normal functioning, growth, and maintenance of the body.

4. Understanding Vitamins Fat soluble vs. water-soluble – Fat-soluble: vitamins A, D, E, K Absorbed with fat, with lymphatic system Stored in larger quantities – Water-soluble: 8 B vitamins and vitamin C Absorbed into the bloodstream Stored in small amounts – Which is more vulnerable to cooking losses?

5. Understanding Vitamins Food preparation affections vitamin content in the foods – Factors that determine amounts: 1.Source 2.Sunlight 3.Moisture 4.Growing conditions 5.Plant’s maturity at harvest 6.Packaging and storage

6. Understanding Vitamins Vitamins in foods – Enrichment and fortification Enriched Fortified Some is required by law – Provitamins Inactive forms of vitamins

7. Vitamin A: The Retinoids Functions – Vision, cell development and health, immunity Food sources – Preformed vitamin A: liver, milk, egg yolks – Beta-carotene: yellow/orange fruits and vegetable

8. Forms of Vitamin A Three active forms of Vitamin A, collectively known as Retinoids: 1.Retinol 2.Retinal 3.Retinoic acid Carotenoids: precursors of vitamin A

9. Functions of Vitamin A 1.Vision: night and day – Night and color vision – Becomes part of the retina 2.Cell production and differentiation – Regulate production of enzymes, blood carrier proteins, and structural proteins – Cell differentiation 3.Skin – Required to replace epithelial cells, which make up epithelial tissues

10. Functions of Vitamin A (cont.) 4.Immune Function – Produce immune cells to fight microorganisms 5.Reproduction – Keeps reproduction tracts healthy – Cell differentiation contributes to embryo development during pregnancy 6.Bones – Trigger an increase in osteoclasts; this contributes to bone “remodeling”

11. Vitamin A Dietary Recommendations – Retinol activity equivalent (RAE) = 1 ug retinol Uses RAE to account for differences between retinoids and carotenoids Sources of vitamin A – Animal: retinoids – Plant: provitamin A carotenoids – Fortified foods

12. Vitamin A Deficiency 1.Eyes – Xerophtalmia 2.The skin and other epithelial cells – Hyperkeratosis 3.Immune function – Vulnerable to infection 4.Other effects: – Growth retardation, bone deformities, defective teeth, kidney stones

13. Vitamin A Toxicity Symptoms: – fatigue, vomiting, abdominal pain, bone and joint pain, loss of appetite, skin disorders, headache, blurred or double vision, and liver damage 1.Teratogen – Causes birth defects 2.Discoloration of skin 3.Acne Treatment: – Retin-A and Accutane

14. The Carotenoids Plant pigments (deep yellow, orange, red color) Can be converted to vitamin A – Beta-carotene supplies the most vitamin A of the carotenoids. Functions: 1.Vision 2.Lower risk of certain cancer

15. The Carotenoids Food sources: – Orange/yellow fruit and vegetables (tomatoes, apricots, carrots), dark green vegetables – Absorb 20-40% of what we eat – Dietary fat and cooking with heat (breaks down cell walls) increases absorption

16. Vitamin D Forms and formations: – Activated in liver and kidney In the skin, UV light converts a form of cholesterol to D3  to liver  dietary and synthesized forms of vitamin D are converted to an intermediate form  goes to kidneys  active form: 25-hydroxyvitamin D [25(OH)D] or calcitrol – Functions: Essential for bone health Regulate blood calcium levels

17. Vitamin D Sources: – Sun exposure helps activate an inactive form of vitamin D – Fortified milk – Fortified food Question: Why would manufacturers choose milk to be fortified with vitamin D?

18. Problem Set 9 Question #1 Name at least three reasons why people around the world will not have similar levels of vitamin D.

19. Vitamin D Deficiency: – In children: Rickets – In adults: Osteomalacia or “soft bones” Osteoporosis Toxicity – Hypercalcemia: a high concentration of calcium in blood  excess deposit of calcium in soft tissues Fun Topic: Melanin and Tanning

20. Vitamin E Forms – 8 similar compounds Essential: alpha-tocopherol – Stored mainly in body fat Functions – Antioxidant Protects cell membranes from free radicals

21. Vitamin E Food sources – Nuts, seeds, vegetable oil, whole grain, wheat germ oil, fruit, vegetables, and animal products Deficiency – Occurs with fat malabsorption – Rare genetic disorder Toxicity – Nontoxic and adverse effects have not been found – Can interfere with blood clotting

22. Vitamin K Forms: – K1 – K2 Functions: – Blood clotting (also requires calcium) – Bone formations Food sources; – Green vegetables (spinach, broccoli, brussel sprouts), plant oils, intestinal bacteria

23. Vitamin K Deficiency – Rare in healthy people – Newborn baby at risk Toxicity – Can interfere with anticoagulant medications – Toxicity is rare

24. Summary of Fat-Soluble Vitamins

25. The Water-Soluble Vitamins: Eight Bs and a C Primarily coenzymes Antioxidants What to keep in mind about each vitamins: – Function – Food sources – Toxicity vs. Deficiency

26. What is a Coenzyme? Coenzyme: a small compound that helps enzymes in biochemical reactions. Most coenzymes are derived from vitamins or are made from vitamins.

27. Thiamin/B1 Functions: – Coenzyme in energy metabolism – Part of the coenzyme: thiamin pyrophosphate (TPP) Food sources: – Pork, legumes, nuts and seeds, fish and seafood, enriched grain product – Cooking reduces content

28. Thiamin/B1 Deficiency: – Beriberi: overall profound muscle weakness and nerve destruction “I can’t, I can’t” – Q: Why would Beriberi be more common in Southeast Asia? Toxicity: – None reported

29. Riboflavin/B2 Functions: 1.Coenzyme in energy metabolism (extracts energy from glucose, fatty acids, and amino acids) 2.Supports antioxidants Food sources: – Milk and dairy products – Enriched grains, eggs Deficiency: – Arbioflavinosis Toxicity: UL is not set

30. Niacin/B3 Functions: 1.Coenzyme in energy metabolism 2.Supports fatty acid synthesis Food sources: – Can be made from tryptophan Need B1, B6, and iron to convert to B3 – Whole and enriched grains – Meat, poultry, fish, nuts, peanuts

31. Niacin/B3 Deficiency: – Pellegra: “rough skin” Four D’s: dermatitis, diarrhea, dementia, and death – Can worsen if also deficient in B1, B6, and iron. Toxicity and medicinal uses – High doses used to treat high blood cholesterol – Side effects: skin flushing, liver damage

32. Pyridoxine/B6 Functions: 1.Coenzyme in protein and amino acid metabolism 2.Supports immune system 3.Helps to lower blood levels of homocysteine  reduce risk for heart disease Diagram: Food sources: – Meat, fish, poultry, potatoes, bananas, sunflower seeds

33. Pyridoxine/B6 Deficiency – Microcytic hypochromic anemia Can also be caused by deficiency in iron. Toxicity – Can cause subtle neurological damage – Other symptoms: upset stomach, headaches, sleepiness, tingling/prickling or burning sensation

34. Folate/B9 Functions: 1.Coenzyme in DNA synthesis and cell division 2.Needed for normal red blood cell synthesis 3.Works with B6 and B12 to help control homocysteine levels Food sources: – Fortified cereals, enriched grains – Green, leafy vegetables

35. Folate/B9 Deficiency: 1.Megaloblastic anemia 2.Birth defects in the Neural Tube: Spina Bifida 3.Heart disease from elevated homocysteine levels Toxicity: – Can mask vitamin B12 deficiency when you take folate supplements

36. Cobalamin/B12 “Cobalt-containing compounds” (cobalamin) Functions: 1.Needed for normal folate functions DNA and red blood cell synthesis Metabolize homocysteine 2.Maintains myelin sheath around nerves  nerves protection Food sources: – Only animal foods: meats, liver, milk, eggs – Some fortified foods

37. Cobalamin/B12 Absorption: – Requires adequate stomach acid and intrinsic factor Deficiency: – Can be caused by Pernicious anemia: autoimmune disorder that damages stomach linings  reduced B12 absorption – Nerve damage Toxicity: – No UL set

38. Pantothenic Acid/B5 Function: 1.Component of coenzyme A  extract energy from nutrients and help build fatty acids Food sources: – Widespread in foods – Reduced by freezing, canning, refining Deficiency/Toxicity: Rare

39. Biotin/B7 Functions: – Acts as a coenzyme in: 1.Amino acid metabolism (amino acids  glucose) 2.Fatty acid synthesis Food sources: – Cauliflower, liver, peanuts, cheese – Protein avidin (raw egg whites) binds biotin and prevents absorption Deficiency and Toxicity are rare

40. Vitamin C Functions: – Antioxidant – Needed for collagen synthesis – Enhances the absorption of iron from plant foods Food sources: – Fruits: citrus, strawberries, kiwi – Vegetables: broccoli, tomatoes, leafy green, potatoes

41. Vitamin C Deficiency: – Scurvy Toxicity: – May cause GI distress – For some people: kidney stones, iron toxicity

42. Summary of Water-soluble Vitamins

43. Choline: A Vitamin-Like Substance Function: – Act as a catalyst to help metabolize homocysteine Food sources: – Milk, liver, egg yolk, peanuts; overall is abundant in food Deficiency: Unlikely in healthy people Toxicity: – Diarrhea, falling blood pressure, fishy body odor

44. Bogus Vitamins Bogus vitamins: Unnecessary substances found in some supplements – Examples: hesperidin, para-aminobenzoic acid (PABA), pangamic acid, rutin – Think twice before you buy them!