Ascorbic acid protects lipids in human plasma and low-density-lipoprotein against oxidative damage

Article Abstract:

Free radicals are highly reactive atoms that have an unpaired electron. They are generated as a normal by product of many different chemical reactions in the body and are strong oxidizing agents. They damage cell membranes, proteins, enzymes, lipids and DNA, and they are believed to play important roles in cancer, aging, atherosclerosis, and autoimmune diseases. Ascorbic acid (vitamin C) is called an antioxidant because it inactivates free radicals and protects against oxidative damage. Other antioxidants present in human blood include uric acid, alpha-tocopherol, ubiquinol-10, bilirubin and beta-carotene. A study was performed to evaluate the effectiveness of these antioxidants in protecting blood proteins and lipids (fats) from oxidative damage. Blood samples from human volunteers were exposed to free radicals from three different sources: AAPH (a chemical that causes free radicals to form); cigarette smoke; and activated neutrophils (white blood cells that produce oxygen radicals). When the blood samples were exposed to these substances, ascorbic acid protected blood proteins and lipids, including low-density-lipoprotein (a lipid that carries cholesterol in the blood), from oxidative damage. However, when ascorbic acid was removed from the blood, the blood proteins and lipids were oxidized. When ascorbic acid was again added to the blood, oxidation stopped. These results indicate that ascorbic acid protects the blood from oxidation caused by free radicals, and that ascorbic acid is one of the most potent antioxidants in the blood. Further research may determine whether vitamin C can be used to prevent degenerative diseases that are caused or worsened by oxidative stress. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prevention, Oxidation, Physiological, Physiological oxidation, Lipoproteins, Oxidation-reduction reaction, Oxidation-reduction reactions, Vitamin C, Blood lipoproteins, Free radicals (Chemistry), Free radicals

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Physical training and copper, iron, and zinc status of swimmers

Article Abstract:

Athletes and coaches often seek information about the role of nutrition in physical performance. Such information is sometimes limited, especially concerning minerals such as copper, iron, and zinc. These nutrients, often in minute amounts, are critically important for many body reactions. Changes in the requirements for these trace elements may occur as a result of physical training, but this is not clear. The effects of training on copper, iron, and zinc metabolism were studied. No evidence of impaired trace element status was found in 29 swimmers (16 female, 13 male) as compared with 28 nonathletes. Plasma levels of copper, iron, and zinc were normal, while activity of an important copper-requiring enzyme, superoxide dismutase, increased in swimmers. This change indicated that copper metabolism successfully adapted to the aerobic training. It was concluded that copper, iron and zinc nutrition do not suffer adverse effects from physical training, as long as the amounts obtained from the diet are adequate. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Food and nutrition, Athletes, Physical education and training, Physical education, Copper in the body, Copper (Nutrient), Trace elements in nutrition, Micronutrients, Swimmers

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