Can Too Much Selenium Be Toxic?
The government has set the tolerable upper intake level (UL) for selenium at 400 mcg for people ≥ 14 years of age. Selenium toxicity is rare in the United States. However, when it occurs, symptoms may include:
- Garlicky breath
- Hair loss
- General weakness
- Stomach upset
- White, blotchy nails
- Mild nerve damage
How Can Selenium Affect My Health?
Some studies that have examined selenium intakes and blood selenium levels effect on cancer. Some of these studies have suggested that people with greater intakes of selenium are less likely to develop
or to die from cancer if they already have it. However, other studies have not found selenium to be protective for cancers.
If selenium affects cancer, it is thought to be due to its action as an antioxidant. Also, it may be that selenium helps stimulate the immune system, making it better able to fight cancer.
In population studies, people with low intakes of selenium have been found to have a greater incidence of heart disease, while those with higher selenium intakes have lower risks for heart disease.
Again, selenium's action as an antioxidant is likely the means by which it protects the heart. Selenium and other antioxidants help limit the oxidation of LDL ("bad") cholesterol. This oxidation leads to plaque build-up on artery walls, and subsequently, heart disease.
Free radicals can promote inflammation and destroy cartilage and collagen in joints, contributing to the pain of
As an antioxidant, selenium can help limit free radical production and therefore ease the pain of arthritis.