Side Effects of Selenium

Selenium is an essential mineral for many plants and animals. The selenium requirement for plants varies, depending on the species. Some plants accumulate this micronutrient as a defense mechanism, whereas some species do not require selenium at all. In humans, this mineral plays an important role in enzymatic reactions of the cell. Selenium acts as a cofactor for various enzymes such as those of antioxidants and thyroid hormones. To be precise, selenium helps in blood clotting and stimulates the immune system.

In normal healthy kids and adults, there are no cases of selenium deficiency. Usually, children suffering from kwashiorkor have low levels of selenium. Hence, it can be concluded that selenium deficiency is related to the deficiency of proteins. In adults, low level of selenium can cause excess fatty deposits in the liver, resulting in fatty liver syndrome. They are also more susceptible to viral infections. Studies have revealed that people with intestinal problems are at a higher risk of developing selenium deficiency.

Selenium Uses and Side Effects

Selenium, in the form of selenium sulfide, is used in anti-dandruff shampoos and other skin lotions. Though there is no sufficient data that proves the therapeutic uses of selenium, it is claimed that selenium supplements can be used for the treatment of tuberculosis, diabetes, heart disease, cancer and AIDS. Selenium supplements are also used for treatment of vitamin E deficiency, muscle pain, arthritis, growth problems, asthma, anemia and mercury toxicity.

The recommended daily allowance (RDA) is 200 mcg, which can be achieved from the daily diet plan. Some of the selenium-rich foods are noodles, macaroni, egg, seafood, cod, poultry and beef. Brazil nuts contain the highest amount of selenium and it is suggested that consuming one raw Brazil nut is enough to provide the daily requirement of selenium. In general, a normal dietary intake of selenium does not cause any noticeable side effects.

Selenium side effects occur with excess administration of selenium supplements. It is also to be noted that consumption of about five times the normal dietary intake leads to certain medical problems. Selenium, in higher doses, causes toxicity known as selenosis. Consumption of more than 400 mcg selenium per day can lead to selenosis. An individual with selenium toxicity will manifest bad breath that resembles garlic odor, which is due to the presence of dimethyl selenide in the exhaled air. Following are the common side effects of excess selenium intake.

• Digestive problems such as nausea, vomiting, stomach pain and diarrhea.
• Effects on mental health that may lead to lightheadedness, peripheral neuropathy, irritability, stress and depression.
• Skin problems like rash, dermatitis and flushing.
• Thickening or loss of fingernails; affected nails are susceptible to infection.
• Metallic taste in the mouth along with difficulty in breathing.
• Malfunctioning of the vital organs - liver, kidney and heart.
• Presence of selenium in the urine sample.
• Cardiovascular problems like heart damage, heart failure and cardiac arrest.

If any of these symptoms is observed after administration of selenium supplements, it is advisable to seek advice from a qualified physician. Side effects of selenium, if untreated, can be life-threatening. Selenium intake is not recommended for children, pregnant women and lactating mothers. Always consult a physician before using any of the selenium supplements.