Vitamin E.pdf

HNUT10010 HNUT10020 Human Nutrition 1: Understanding Nutrients Aifric O’Sullivan BSc, MSc, PhD UCD Institute of Food and Health School of Agriculture and Food Science Vitamin E Vitamin E Foods AI 0.4mg -tocopherol equiv/g dietary PUFA -tocopherol (mg) -tocopherol (mg) 1 tablespoon 1.9 0....

HNUT10010 HNUT10020 Human Nutrition 1: Understanding Nutrients Aifric O’Sullivan BSc, MSc, PhD UCD Institute of Food and Health School of Agriculture and Food Science Vitamin E Vitamin E Foods AI 0.4mg -tocopherol equiv/g dietary PUFA -tocopherol (mg) -tocopherol (mg) 1 tablespoon 1.9 0.1 Soybean oil 1 tablespoon 1.1 8.7 Corn oil 1 tablespoon 1.9 8.2 Canola oil 1 tablespoon 2.4 3.8 Safflower oil 1 tablespoon 4.6 0.1 Sunflower oil 1 tablespoon 5.6 0.7 Almonds 1 ounce 7.4 0.2 Hazelnuts 1 ounce 4.3 0 Peanuts 1 ounce 2.4 2.4 Spinach ½ cup, raw 0.3 0 Carrots ½ cup, raw chopped 0.4 0 2.7 0.4 Food Serving Olive oil Avocado (California) 1 fruit Vitamin E The vitamin E vitamers, tocopherols and tocotrienols Cannot interconvert The Nutrition Society Textbook Series, Introduction to Human Nutrition, Second Edition © 2009, 2002 -tocopherol Equivalents • Different vitamers have different biological potency • -tocopherol is the most active • -tocopherol Equivalents = – mg -tocopherol + 0.5 x mg β-tocopherol + 0.1 x mg -tocopherol + 0.3 x mg -tocotrienol -tocopherol Equivalents mg -tocopherol + 0.5 x mg β-tocopherol + 0.1 x mg -tocopherol + 0.3 x mg -tocotrienol Sunflower Oil Soybean Oil -tocopherol 48.7 10.1 β-tocopherol 5.1 59.3 -tocopherol 0.8 26.4 -tocotrienol 0 0 Sunflower Oil = 48.7 + (0.5 x 5.1) + (0.1 x 0.8) + (0.3 x 0) = 51.33 mg Soybean Oil = 10.1 + (0.5 x 59.3) + (0.1 x 26.4) + (0.3 x 0) = 80.99 mg Vitamin E Absorption and Metabolism VLDL transports to other tissues +E Chylomicron +E Antioxidants • • • • Neutralize free radicals Donate an electron End the chain reaction Antioxidants remain stable Antioxidant A dietary antioxidant is a substance in foods that significantly decreases the adverse effects of reactive species, on normal physiological function in humans. Free Radical Vitamin E: Antioxidant Function Free Radical Cascade • When a molecule has an unpaired electron it is highly reactive • The free radical will search for a stable molecule to steal an electron • This can create a cascade of destruction • The once stable molecule forms an new free radical and seeks another stable molecule... Free Radicals • Damage – Cell membranes – DNA – RNA – Proteins • Effect – Transport in and out of cells – Impair cell function – Illicit inflammatory response Not always bad – white blood cells generate oxygen radicals to help fight invading pathogens Vitamin E Metabolic Function • Limits radical damage from oxidation of PUFAs Tocopheroxyl radical Non-radical product • Vitamin E radical reduced back to tocopherol by reaction with vitamin C The Nutrition Society Textbook Series, Introduction to Human Nutrition, Second Edition © 2009, 2002 Nutrients With Antioxidant Activity Body’s defence mechanisms Antioxidant vitamins • Vitamin C • Vitamin E • Beta-Carotene Example of the interconnection between many micronutrients Cofactors Enzymes • Zinc • Selenium • Copper • Manganese Defending Against Disease Dietary Antioxidants Low antioxidant intake in diet Free Radicals Oxidative Stress = increase disease Age related decline in natural defence Exposure to toxins Cigarette Poor nutrition Stress Ultra violet light Defending Against Disease • At high levels free radicals cause damage to cells damaging and may contribute to cellular dysfunction and disease. – Cancer – Cardiovascular Disease – Cataracts – Age Related Macular Degeneration – Alzheimer’s – Diabetes Vitamin E Metabolic Function • Epidemiology studies show a clear association between high blood concentrations of vitamin E and lower incidence of CVD • Randomised controlled trials with high dose vitamin E supplements have been disappointing – Small effect – No effect – Increased health risks Reading • Gibney M, Lanham-New S, Cassidy A, Vorster H, eds. Introduction to Human Nutrition. 2nd ed: Wiley-Blackwell, 2009. Chapter 8 • Gropper SS, Smith JL. Advanced Nutrition and Human Metabolism, International Edition 6th ed: Wadsworth Cenage Learning, 2013. Chapter 9/10 • Whitney E, Rolfes SR. Understanding Nutrition, 13th Edition: Wadsworth, Cengage Learning, 2013. Chapter 10/11 Other • National Research Council. Washington, DC: The National Academies Press – Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc – Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids – Dietary Reference Intakes for Calcium and Vitamin D . Washington, DC