CL ASS NOTE S NOV 11 2013 NUTRI TION CONCEPTS Highlight 11 Free Radicals and Disease Free radical Unstable molecule with one or more unpaired electrons Production Environmental factors Look to steal electron from vulnerable compound Electron snatching chain reaction Normal bodily functions Ultraviolet light air pollution tobacco smoke Oxygen reacts with body compounds produces free radicals Antioxidants Donate an electron neutralize free radicals end chain reaction Free radical attacks Antioxidants are stable in various forms therefore do not become free radicals Some are helpful defense against viruses and bacteria Most cause damage Damage polyunsaturated fatty acids in lipoproteins and membranes disrupts transport of substances into out of cells Contribute to cell damage disease progression and aging Alter DNA RNA and proteins Free radical damage Creates excesses de ciencies of speci c proteins impairs cell functions elicits in ammatory response Body s natural defenses and repair systems Not 100 percent effective Less effective with age Oxidative stress Can occur when antioxidants are or free radicals are Oxidative stress causative and antioxidants protective in Cognitive performance Cancer diabetes hypertension heart disease Arthritis and cataracts Defending Against Free Radicals System of enzymes against oxidants Copper selenium manganese and zinc CL ASS NOTE S NOV 11 2013 NUTRI TION CONCEPTS Antioxidant vitamins Vitamin E Beta carotene Vitamin C Defends lipid membranes Defends body lipids by stopping free radical chain Protects other tissues i e skin and uid of blood against free radical attack Antioxidant Roles Dietary antioxidants defend against cancer and chronic disease Limit free radical formation Destroy free radicals or precursors Stimulate antioxidant enzyme activity dietary antioxidants minerals all work together to make sure that antioxidant enzymes and repair enzymes are working Repair oxidative damage Stimulate repair enzyme activity Support a healthy immune system Defending Against Cancer Cancers due in part by damage to cellular DNA Vitamin C unique situation Vitamin E Antioxidants may protect DNA from this damage Inverse relationship with vegetable intake Positive relationship with beef and pork intake as those go up risk for cancer also rises High beta carotene one of the key factors but no evidence supporting supplementation In high doses might act as a pro oxidant can be a concern for some nutrients but not in this situation generate free radicals possibly useful in destruction of cancer cells research inconclusive May inhibit cancer formation by attacking free radicals that damage DNA research inconclusive every time isolate don t always get desired results from food is best bene ts CL ASS NOTE S NOV 11 2013 NUTRI TION CONCEPTS Defending Against Heart Disease Increased LDL increased risk for heart disease but the oxidation for LDL is above the ratio What s causing the Accelerate formation of artery clogging plaques Additional changes in arterial walls clogging is the oxidization Oxidized LDL scenario Vitamin C E protection Diet high in foods rich in vitamin E reduced atherosclerotic plaques and risk for heart disease Vitamin C protects against LDL oxidation increases HDL and decreases total cholesterol improves blood Supplements are less clear Foods give best reduced risks and bene ts Supplement ef cacy is less clear Risk of Vitamin E supplement use by those who already have heart disease is not recommended pressure may minimize in ammation and free radical action in arterial wall Foods Supplements or Both Must replenish dietary antioxidants regularly Physiological levels vs pharmacological doses where we see when we have too high of a dose basically a drug reaction and potential side effects Antioxidants and other valuable nutrients Antioxidant actions of fruits and vegetables are greater than their nutrients alone Foods Supplements Contents are limited CL ASS NOTE S NOV 11 2013 NUTRI TION CONCEPTS Review Antioxidants What is a free radical When do they occur In excess antioxidants can act as pro oxidants Antioxidants can protect against disease examples are the protection the following from free radical damage DNA cell Molecule that oxidizes others unstable missing electrons Can cause oxidative damage Occur in ultra violet rays pollution tobacco smoke and everyday daily life membranes
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