Nancy's Nutrition Corner

"Let food be thy medicine and medicine be thy food," Hippocrates.


One thing I have often written about in this column is the damage done in the body by free radicals. This month I want to talk about selenium, a mineral that serves as a protective agent for cells against destruction by free radicals. Selenium works in a supporting role with an enzyme called glutathione peroxidase. You can think of these two as the Batman and Robin of free radical mayhem.

Every day, an abundance of free radicals are created in our bodies as a result of exposure to environmental insults such as smog, chemicals, drugs, radiation, and as a byproduct of normal physiological processes. Once formed, free radicals “attack” by taking electrons away from the DNA, proteins, and fatty acids within our cells. Damage to these cellular components has been implicated as the cause of dozens of diseases including atheroscelorsis, cancer, premature aging, and many others. The primary mechanism by which the body gets rid of free radicals is by converting them to other compounds with the help of antioxidant nutrients such as vitamins C, and E, and enzymes such as glutathione peroxidase. This enzyme is found in cells throughout the body and has a crucial role in this fight, but it requires the presence of the mineral selenium to carry out its duties.

Interestingly, the concentration of selenium in soil varies greatly throughout the world. This results in a variable concentration in the food depending on the soil in which it was grown. This uneven distribution makes it easy to see the correlation between selenium poor diets and the diseases associated with selenium deficiency. Tissues containing high amounts of selenium include the heart, muscle, kidney, and bone. Not surprisingly, severe selenium deficiency leads to diseases such as congestive heart failure and degeneration of the joints. Less severe deficiencies of selenium have been connected to cardiovascular disease, cancer, muscle pain, weakness, and impaired function of the immune system.

Excellent sources of selenium include cold water fish, shellfish, and Brazil nuts (just one nut a day will fulfill daily requirements). Very good sources include sunflower seeds, barley, oats and chicken eggs.

Nancy Silva, ND is a licensed naturopath with a penchant for good food. Her monthly column discusses the nutritional aspects of some of the foods available through LocalHarvest. You can contact Nancy from her listing on our website.

Back to the May 2009 Newsletter