1.1. • Unessential in the diet • Calciferol – Vitamin D2 (plant foods in diet) – Vitamin D3 (animal foods in diet and sunlight)
1.2. Vitamin D roles • Assisting in the absorption of calcium and phosphorus • Bone growth and health • Brain and nerve cells • Muscles • Immune system
1.3. Vitamin D deficiency • Dark skin, breastfeeding, lack of sunlight • Calcium uptake hindered • Osteoporosis • Rickets (bowed legs and beaded ribs) • Elderly – Little milk consumption – Impaired organ function – Spend most of their time inside
1.4. Vitamin D toxicity • Likely candidate for toxicity • Supplements • Increase in calcium • Calcification, stone forming
1.5. Vitamin D recommendations • Assumes no sunlight • Vitamin D fortified foods • Egg yolk, oily fish • Sunlight – Hands, face and arms on a clear summer day for 5-10 minutes, 2-3 times a week
2. Interplay of Vitamins
2.1. • Vit. E deficiency impairs vit. A absorption and storage • Vit. A, D and K play important roles in bone growth • Vit. K synthesizes bone protein, vit. D regulates this, while vit. A controls the genes for this • Vit. E and K can impair each other.
3. Vitamin B12
3.1. • Synthesis of DNA • Protects nerve cells and their normal growth • Bone cell activity and metabolism • Hydrochloric acid and pepsin release vitamin B12 from protein – Intrinsic factor • Excess secreted via the gall bladder • Deficiency related to poor absorption – Hydrochloric acid – Intrinsic factor • Neurological degeneration • Anemia – interplay with folate! • Animal derived – Vegetarians milk and eggs – Vegans fortified foods • Microwave heating inactivates B12
4. Folate/ folic acid
4.1. • Converts vitamin B12 to its active coenzyme form • Synthesizes DNA for rapidly growing cells • Excess is excreted via the gallbladder • Alcohol • Synthetic folate 1.7x more available than naturally occurring folate Folate • Deficiency related to impaired cell division and protein synthesis – Red blood cells (anemia) – GI tract cells • Primary deficiencies • Secondary deficiencies
5. Vitamin B6
5.1. • Family of compounds – Pyridoxal – Pyridoxine – Pyridoxamine • Coenzyme PLP (pyridoxal phosphate) – Can add and remove amino groups – Very important in metabolism • Can be stored in the muscles • Deficiency related to diminished neurotransmitter synthesis – Depression, confusion, convulsions – Alcohol related to deficiency • Toxicity found in over-consumers (20x UL) caused neurological damage
6. Vitamin B2
6.1. • Coenzyme in energy metabolism • No recommendations • Deficiency accompanied by other nutrient deficiencies – Inflammation of the GI tract • Destruction due to UV light and irradiation – Milk
7. Vitamin A
7.1. • Three different active forms, commonly animal derived: – Retinol – Retinal – Retinoic acid • Carotenoids are plant derived – Beta-carotene, greatest vitamin A activity • RAE – retinoid activity equivalents
7.2. Roles of vitamin A • Gene regulator • Antioxidant (beta-carotene) • Promotes vision – Retinal • Protein synthesis, cell differentiation and growth – Retinoic acid • Supports reproduction – Retinol and retinoic acid
7.3. Vitamin A and vision 1. In the eye, retinal is bound to opsin - Together called rhodopsin 2. When light strikes the retina, opsin is released 3. Retinal shifts from a cis to a trans configuration 4. This generates an electrical impulse, sent to the brain 5. Some retinal may convert back, but is sometimes oxidized.
7.4. Vitamin A and cells • The body is a tube, covered by cells • Vitamin A promotes cell differentiation – Cells lining the body, inside and outside – Mucus producing cells • Normal foetal growth
7.5. Vitamin A status • 90% is stored in the liver • Deficiency is uncommon – Needs 1-2 years to completely deplete storage – Developing countries • Blindness (night and total) • Immune functions (measles, malaria, HIV)
9.1. • Two subgroups, each with different members – Tocopherols – Tocotrienols • Alpha-tocopherol • Antioxidant • Deficiency rare – premature infants • Toxicity rare – may interfere with vitamin K blood clotting
10. Vitamin C
10.1. • Ascorbic acid • Antioxidant • Free radicals – Unpaired electrons – Unstable – Highly reactive • Oxidative stress • Enhances iron absorption – Prevents iron oxidation • Cofactor – Activates enzymes • Connective tissue – Collagen – Iron and vitamin C are needed • In stress – Infections – Burns – Heavy metals – Smoking – Medicine • Common cold
11. Vitamin B3
11.1. • Nicotinic acid • Nicotinamide: major form in blood • Coenzyme forms: NAD and NADP • Recommendations: – Niacin equivalents (NE) – Tryptophan 60:1 • Pellagra – Diarrhea, dermatitis, dementia and death • Toxicity at 3-4 times the RDA, “niacin flush” – Supplements, not diet
12. Vitamin B1
12.1. • Coenzyme for pyruvate to acetyl CoA • Nerve and muscle activity • No recommendations • Deficiency when you fail to eat enough food – Malnourished – Homeless – Alcoholics • Heat unstable, leaches into boiled water – Steaming – Microwave
