Vitamins Biochemistry PDF

Vitamins In Depth of Chapter 7 Six classes of nutrients Macronutrients Micronutrients Carbohydrates Vitamins Lipids Minerals Proteins Water 8-2 Characteristics of Vitamins Vitamins are organic com...

Vitamins In Depth of Chapter 7 Six classes of nutrients Macronutrients Micronutrients Carbohydrates Vitamins Lipids Minerals Proteins Water 8-2 Characteristics of Vitamins Vitamins are organic compounds assisting in regulating body processes. Micronutrients – thus needed in small amounts NOT a source of ENERGY 13 Vitamins are considered essential Vitamin Classified; Fat Soluble & Water soluble 8-3 Fat Soluble Vitamins 8-4  Vitamins A, D, E, K Found in fatty portions of food (ex. Cod liver oil) Absorbed along with dietary fat Stored in adipose tissue - can build up in Fat-Soluble adipose, liver & other tissues and reach toxic levels Vitamins Vit A & D are the most toxic - megadosing can result in tissue damage Symptoms of overconsumption: damage to hair, skin, bones, eyes, irreversible organ damage and death Vitamin A Fat soluble vitamins Functions: require proteins (binding proteins & Healthy Vison - reacts to changes in chylomicrons) for transport through the light/ distinguish between different bloodstream to the tissues. wavelengths Active forms of Vitamin A collectively Antioxidant – protects low-density called retinoids: lipoproteins from becoming oxidized Retinol (beta-carotene converted to retinol in the walls of intestines) Reproductive function – essential for Retinal sperm production AND egg fertilization Retinoic acid Essential for cell differentiation - Such as T-lymphocytes, specialized cells lining trachea/bronchi/GI tract RDA of Vitamin A Recommended Daily Allowance (RDA) 900 µg/day for men; 700 µg /day for women 8-7 Vitamin D Functions: Since fat soluble…requires Maintains bone & muscle proteins (binding proteins & health chylomicrons) for transport through the bloodstream & Aids in Absorption of Calcium, tissues. Magnesium & Phosphorus Regulates blood calcium Forms of Vitamin D level D2 (Ergocalciferol) – occurs in Essential for cell differentiation plants, animals & mushrooms D3 (Cholecalciferol) – found only Research shows it leads to a reduction in in animals - thought to be more colon cancer easily absorbed  Recommended Daily Allowance (RDA) Adults 19-70 15 µg/day Adults >70 yrs 20 µg/day RDA of Canadians should take 25 µg (1000 IU) in fall/winter months. Vitamin D UL is 100 µg/day Check this article out… Vitamin E Functions: Powerful Antioxidant - donates an e⁻ to free Since fat soluble…requires fats to transport radicals and becomes oxidized – sparing it from intestine to other molecules Protects low-density lipoproteins (LDLs) Forms of Vitamin E from being oxidized – reducing risk of heart disease Tocotrienols – inactive forms must be converted inside the body to be used Protects RBC from being oxidized - reducing risk of anemia Tocopherols – active forms can be used as Protects WBC/macrophages from being is - alpha (most active), beta, gamma & oxidized - enhancing immune system delta Anticoagulant - lessens the stickiness of cells lining blood vessels Improves absorption of Vitamin A RDA of Vitamin E Recommended Dietary Allowance 15 mg/day of alpha-tocopherol (men and women) Upper limit (UL) is 1,000 mg per day 8-11 Food Sources  Vitamin C (ascorbic acid) & B-vitamins (thiamin, riboflavin, niacin, B12, folate etc) Water Soluble Absorbed through intestinal tract to bloodstream Vitamins Except for Vitamin B12, we do not store these vitamins Excreted in urine Toxicity is rare, but can cause nerve damage and skin lesions Best Sources of Water-Soluble Vitamins Found in whole grains, whole fruits, whole vegetables  Retaining the Vitamins in Food Exposure to oxygen Oxygen can destroy water-soluble vitamins & fat-soluble vitamin A, E & K Fruits/vegetables should be stored in airtight container Exposure to UV light fruits, vegetables, milk and grains stored in glass containers lose vitamins…milk is sold in opaque container Traditional methods of sun-drying fruits/vegetables destroy vitamins such as beta-carotene and Vit C. Exposure to Water Water-soluble vitamins leach out of foods when soaked/cooked in liquid Steam of microwave vegetables to minimize leaching Exposure to Heat Avoid high heat for long periods of time, heating destroys water soluble vitamins (microwave/steam/stir fry is best) 8-15