USF-COM Department of Family Medicine

Patient Education Information on... Index of Patient Education Topics

INTRODUCTION

Antioxidants are a group of vitamins, minerals and enzymes that may reduce the risk of some forms of cancer, heart disease and strokes.  Some antioxidants are manufactured by our bodies while others must come from the diet.   Dietary antioxidants include folate, Vitamins A, C, and E, the mineral selenium, and certain substances called “phytochemicals” found in fruits and vegetables.

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MECHANISM

Oxygen is part of the air you breath and is vital to life.  However, when oxygen is metabolized, or used by the body, cells form by-products called free radicals.  These free radicals are also created by exposure to various environmental factors, tobacco smoke and radiation.  If uncontrolled, these free radicals can cause damage to cell walls, certain cell structures, and genetic material within the cells.  Such damage is thought to contribute to aging and various health problems.  Antioxidants protect important cell components by neutralizing the free radicals.  Antioxidants that occur naturally in the body or consumed in the diet may block the damage.  Unfortunately, these defenses are not 100% efficient and the damaged cells may accumulate and contribute to certain diseases.

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EVIDENCE

Several studies have shown an association between antioxidants and disease prevention.  A recent study reported by the American Heart Association Scientific Session showed that women who consumed high amounts of antioxidant containing foods had a 33% lower risk of heart attack and a 71% lower risk of stroke, than women who ate few antioxidant-containing foods.  Individual foods most closely associated with the health benefits included carrots, spinach and other green leafy vegetables.

 The American Academy of Nutritional Research (AANR) reported that antioxidants prevent, slow the progress of, and can even reverse heart disease.  Antioxidants have positive influences on the cholesterol in our blood stream by increasing the levels of HDL, the good cholesterol, and decreasing the levels of LDL, the bad cholesterol.  Furthermore, through their ability to protect against free radical damage, certain antioxidants have been shown to prevent cholesterol from being deposited on the walls of the coronary arteries.  Certain antioxidants also improve blood flow through already diseased coronary arteries by both dilating these arteries to provide better blood flow to the heart muscle as well as minimizing blood clotting in these diseased, narrowed blood vessels.

Many medical studies in the past have shown that low levels of antioxidants in a person’s body is strongly associated with a higher likelihood of many types of cancers, including cancers of the mouth, throat, lung, esophagus, stomach, prostate, and colon.  Antioxidants have been shown to protect our bodies from cancer by supporting and enhancing the immune system, minimizing the influence of germs, especially viruses, in causing cancer

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RECOMMENDATIONS

Despite the promising findings from antioxidant research studies, many experts are not yet convinced there are adequate data to allow a health claim on foods or dietary supplements.  Questions still remain on issues such as the effectiveness of individual antioxidant vitamins.  Many health groups such as the American Cancer Society  and the American Heart Association believe it is premature to recommend dietary supplements containing antioxidants, indicating that some other as yet unidentified substance in fruits and vegetables may actually be responsible for reduced disease risk.  These groups currently recommend increased fruit and vegetable consumption among people with high risk for cardiovascular disease as well as for the general public.  Until further studies are completed, eating a balanced diet rich in antioxidant vitamins may be the best way of improving your health.  Some nutritionists and policy makers are concerned that individuals will take excessive amounts of supplements, believing that if a little bit is good, more must be better.  High doses of some antioxidants can produce adverse effects in people.  Some supplements can be dangerous to certain people, therefore it is best to visit a registered dietician or physician for professional advice.  It is best to remember that vitamin and mineral supplements should never be used as substitutes for a healthy, well balanced diet.

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ANTIOXIDANT RICH FOODS

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 REFERENCES

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