Eating Just Two Brazil Nuts a Day Ensures Adequate Selenium Levels 10-10-08

by: Barbara L. Minton

Brazil nuts are the best way to add selenium to your diet. A recent study at the University of Otago in New Zealand found that eating just two Brazil nuts a day is as effective in increasing selenium status and enhancing glutathione peroxidase activity as a recommended dosage of selenomethionine. Inclusion of this high-selenium food in the diet could avoid the need for fortification or supplements to improve selenium levels.

Researchers operating with the knowledge that Brazil nuts provide a rich natural source of selenium sought to investigate the bioavailability of this selenium in humans. They investigated the efficacy of Brazil nuts in increasing selenium compared to that of selenomethionine, believed to be the preferred supplement because of its high bioavailability. A randomized controlled trial was conducted with 59 New Zealand adults. Participants consumed 2 Brazil nuts, selenomethionine, or a placebo. Plasma selenium and plasma and whole blood glutathione peroxidase activities were measured at baseline and at intervals following treatment.

Changes in plasma selenium and glutathione peroxidase activity in the Brazil nut and selenomethionine groups differed significantly from the placebo group but not from each other. The change in whole blood glutathione peroxidase activity was greater in the Brazil nut group than in the placebo and selenomethionine groups.

Selenium is a trace mineral that is essential to good health but required only in small amounts. It is used in creating important antioxidant enzymes that help prevent cellular damage from free radicals. Free radicals are natural by-products of oxygen metabolism that are seen to contribute to the development of chronic diseases like cancer and heart disease. Selenium is also critical for proper thyroid functioning and plays a role in the immune system.

The content of selenium in food depends on the selenium content of the soil in which plants are grown or animals raised. Much of the overall mineral content of the soils used in modern agriculture is depleted, so people have been turning more and more to supplements to get the needed amount of selenium.

People with gastrointestinal disorders may have decreased absorption of selenium, and people with iodine deficiency are particularly likely to benefit from selenium supplementation. Findings from research recently completed indicate that adequate selenium levels are correlated with reduced levels of breast and prostate cancer. Research is currently underway on the protective effects of selenium in humans against aging, other cancers, heart disease, cataracts, arthritis, Alzheimer’s disease, and HIV infection.

Glutathione peroxidase is the general name of an enzyme family with peroxidase activity whose main role is the protection of organisms from oxidative damage. Its biochemical function is to reduce lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. Glutathione peroxidase is a selenium containing glycoprotein. The integrity of the cellular and subcellular membranes is heavily dependent on glutathione peroxidase, while the antioxidative protective system of glutathione peroxidase itself is dependent on the presence of selenium.