tailieunhanh - Antioxidants and Health: An Introduction

The Physicians’ Health Study II, which included more than 14,000 male physicians aged 50 or older, found that neither vitamin E nor vitamin C supplements reduced the risk of major cardiovascular events (heart attack, stroke, or death from cardiovascular disease), cancer, or cataracts. In fact, vitamin E supplements were associated with an increased risk of hemorrhagic stroke in this study. The Selenium and Vitamin E Cancer Prevention Trial (SELECT)—a study of more than 35,000 men aged 50 or older—found that selenium and vitamin E supplements, taken alone or together, did not prevent prostate cancer. A 2011 updated analysis from this. | credits top to bottom felinda RedHelga kcline IBushuev grafvision Fotografiabasica . DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Center for Complementary and Alternative Medicine Antioxidants and Health An Introduction Antioxidants are man-made or natural substances that may prevent or delay some types of cell damage. Diets high in vegetables and fruits which are good sources of antioxidants have been found to be healthy however research has not shown antioxidant supplements to be beneficial in preventing diseases. Examples of antioxidants include vitamins C and E selenium and carotenoids such as beta-carotene lycopene lutein and zeaxanthin. This fact sheet provides basic information about antioxidants summarizes what the science says about antioxidants and health and suggests sources for additional information. Key Points Vegetables and fruits are rich sources of antioxidants. There is good evidence that eating a diet that includes plenty of vegetables and fruits is healthy and official . Government policy urges people to eat more of these foods. Research has shown that people who eat more vegetables and fruits have lower risks of several diseases however it is not clear whether these results are related to the amount of antioxidants in vegetables and fruits to other components of these foods to other factors in people s diets or to other lifestyle choices. Rigorous scientific studies involving more than 100 000 people combined have tested whether antioxidant supplements can help prevent chronic diseases such as cardiovascular diseases cancer and cataracts. In most instances antioxidants did not reduce the risks of developing these diseases. Concerns have not been raised about the safety of antioxidants in food. However high-dose supplements of antioxidants may be linked to health risks in some cases. Supplementing with high doses of beta-carotene may increase the risk of lung cancer in smokers. .