Selenium is required by the body for proper functioning of the thyroid gland and may help protect against free radical damage and cancer.
A deficiency in selenium can lead to pain in the muscles and joints, unhealthy hair, and white spots on the fingernails. In long-term cases, it may even lead to Hashimoto's disease, a condition in which the body's own immune system attacks the thyroid.
An excess of selenium can lead to bad breath, diarrhea, and even hair loss.
Foods high in selenium include Brazil nuts, tuna, oysters, pork, beef, chicken, tofu, whole wheat pasta, shrimp, and mushrooms. The current daily value (DV) for selenium is 55μg (micrograms).
It is important to note that the amount of selenium in any product varies greatly by the amount of selenium in the soil in which it was produced/grown/raised. Be sure to check individual labels, and if you have a deficiency in selenium, get tested after changing your diet to be sure you are eating adequate amounts.
Below is a list of high selenium foods sorted by common serving size, see the complete ranking of all foods high in selenium to sort by 100 gram and 200 calorie serving sizes.