[[Brazil nuts]] are high in selenium and an ounce (roughly half a dozen) provides 800 micrograms. That's about double the US recommended tolerable upper limit. Overindulging regularly could lead to selenium toxicity. Symptoms may include a metallic taste, garlic odor on the breath, hair loss, brittle nails, fatigue, nausea, rash, diarrhea, runny nose, cough and nerve pain. Selenium-containing supplements are another potential source of this mineral.
==The benefits of Selenium are==
*This mineral helps the body manufacture [[glutathione]], an enzyme required for proper detoxification of the body. Because toxic build-up in the body is linked to cancer, assisting your body with its natural, ongoing detoxification processes helps lessen your risk of cancer. In research, low dietary levels of selenium have been correlated with higher cancer incidence. Supplementation with selenium is a valuable cancer prevention tool.*The mineral selenium is essential for the body's natural production of [[Coenzyme Q10]].<br> ''Natural sources of selenium :''<br>
*Nuts (Brazil Nuts): Nuts, especially Brazil nuts, are a great source of selenium. Brazil nuts, which are also rich in [[magnesium]], provide the most selenium with 1917μg (2739% RDA) per 100 gram serving, 2550μg (3642% RDA) per cup, and 96μg (137% RDA) in a single kernel or nut. Mixed nuts by contrast provide about half as much selenium with 422μg (77% RDA) per 100 gram serving, 607μg (111% RDA) per cup, and 118μg (169% RDA) per ounce.
*Shellfish (Oysters, Mussels, Whelk): In addition to selenium oysters and shellfish are also a great source of iron, zinc, copper, and vitamin B12. Pacific oysters provide the most selenium with 154μg (220% RDA) per 100 gram serving, or 131μg (52% RDA) per ounce, and 38.5μg (55% RDA) per oyster. Other shellfish high in selenium include blue mussels and whelk which provide 90μg (128% RDA) of selenium per 100 gram serving, 76μg (109% RDA) per 3 ounce serving.