> Health and Disease > Immune System > AIDS

Imagine an antioxidant with the power to fight aging, halt heart disease, cut cancer rates, boost immunity, and speed healing. That’s selenium, one of the most important disease-fighting nutrients. Human and animal studies conducted over the past 40 years have shown that optimal intake of this trace mineral can help prevent heart disease, cancer and macular degeneration, slow cellular aging, reduce fat oxidation in the body, inhibit plaque formation in the arteries, and even halt the progress of HIV infection.

Once feared for its toxic effects, selenium has come a long way since 1957, when it was first found to prevent liver damage in animals deficient in vitamin E . The last of 40 nutrients to be proved essential to health, the Recommended Daily Intake (RDI) of selenium is 70 mcg for all men and women.

Selenium has many important functions within the body. As an antioxidant, it plays a major role in offsetting aging by preserving the elasticity of skin and preventing oxidative damage to fat cells. Selenium also serves as a building block in the formation of glutathione peroxidase, a powerful antioxidant enzyme produced within the body. Along with the enzymes catalase and superoxide dismutase (SOD), glutathione peroxidase is one of the body’s primary detoxifiers.

Natural levels of selenium in the blood decline with age, disease, dietary imbalances and excess amounts demanded by drugs or alcohol. Levels also depend on the availability of the amino acid glutathione, which is produced internally and consumed from foods, as well as on selenium intake. Without sufficient amounts of these two key nutrients, optimum levels of glutathione peroxidase can’t be produced, resulting in decreased disease-fighting resistance.

Preventing Disease

In recent years, studies have shown that people with higher blood levels of selenium are significantly less likely to develop many forms of cancer and heart disease than those with lower blood levels. Selenium’s protective effects on the heart stem from its ability to help block oxidation of low-density lipoprotein (LDL) cholesterol, which is a primary step in decreasing atherosclerosis, or plaque formation in the arteries. In arteries, oxidized LDL damaged by free radicals can combine with calcium and harden, forming plaque. In countries such as Finland, where low levels of dietary selenium have been linked to an increased risk of heart disease, supplementation with selenium, either via dietary supplements or through soil supplementation, has been found effective in increasing blood levels of selenium. Increased blood levels of selenium are associated with a reduced risk of cancer and heart disease.

Blood levels of selenium are directly linked to the amount of selenium consumed in the diet. For this reason, many Asian women are believed, in part, to have a lower incidence of breast cancer than their North American counterparts because their diet contains four times more selenium than the average North American’s. Asian women’s diets are also lower in overall fat, especially easily oxidized fats such as the polyunsaturated fats found in common cooking oils.

Selenium and Vitamin E

Selenium works synergistically with vitamin E, and supplementation with both is better than taking either alone. Many cancer and heart disease prevention studies have used a combination of these two nutrients to determine their effectiveness in curbing death rates.

For example, some of the world’s highest rates of esophageal and stomach cancer occur in north central China, where the Linxian cancer trials were done. Not surprisingly, the people in this area have been found to consume subadequate amounts of selenium as well as other nutrients. In the Linxian trial, completed in 1995, participants were put on either one of four supplement regimes or given a daily multiple vitamin/mineral supplement or placebo for more than five years. Of the group receiving one of four different supplement combinations (vitamin A and zinc; riboflavin and niacin; vitamin C and molybdenum; or beta-carotene, vitamin E and selenium), only the latter group showed significant reductions in total as well as fewer cancer-related deaths.

Selenium and AIDS

Frances Albrecht is a certified nutritionist practicing in Seattle, WA.

Source: alive #209, March 2000