Selenium: Health Benefits, Side Effects, Supplements, Foods and Doses

Selenium: Health Benefits, Side Effects, Supplements, Foods and Doses

What is Selenium?

Selenium is a naturally occurring mineral found in the soil, water, and food. Your body only requires traces of selenium which facilitates metabolic processes, reproduction, DNA synthesis, and thyroid function.

In addition, it helps protect your body from oxidative damages and infections. You can get Selenium in dietary supplements. The body stores about 28% to 46% of Selenium in skeletal muscle.

In human and animal tissues, most Selenium is stored in the form of selenomethionine.

Where Does it Come From is there any Food Source?

You can get Selenium from different food sources, but the content varies with soil conditions and location. It is estimated that people in the United States consume an average of 125 micrograms of Selenium every day.

However, people living in Coastal Plain and the Pacific North West consume an average of 60 to90 micrograms of Selenium every day, which is also considered sufficient.

Natural food sources of Selenium include whole grains, fresh and saltwater fish (tuna and red herring), seeds, brown rice, milk, garlic, beef, poultry, walnuts and Brazil nuts. The best sources of Selenium are whole foods because it may become altered during processing.

What are its Possible Health Benefits?

Selenium has several possible health benefits which include:

Selenium Health Benefits
  • Antioxidant Protection: Your body requires selenium for proper function of enzymes referred to as glutathione peroxidases (GPO), which helps in detoxification as well as protects against oxidative stress. In addition, Selenium is essential in recycling vitamin C.
  • Supports Thyroid Function: An enzyme-containing Selenium helps in the transformation of a less active thyroid hormone. Selenium work along with iodine to maintain a strong and consistent thyroid function.
  • Prevents Cancer: Credit to its antioxidant effects, role in DNA repair, endocrine, and immune systems, Selenium is considered to help fight prostate, skin, bladder, lung and colorectal cancers.
  • Cardiovascular Disease: Selenium plays major role in fighting oxidative modification of lipids and prevents platelets aggregation which can lead to cardiovascular disease.
  • Other health benefits include improved fertility, boosted brain function, and eases symptoms arthritis, asthma, and dandruff.

What are the Potential Side Effects of Selenium?

There are no known side effects associated with Selenium when it is consumed in normal doses. However, if you take an overdose, it can lead to heart, kidney, and liver problem.

Other side effects may include weakened fingernails, diarrhea, increased irritability, itchy skin, hair loss, fatigue, nausea, vomiting, fever, and bad breath.

It is important to note that if taken in very high doses, Selenium can be fatal.

Recommended Doses and Timing for Selenium

Recommendation and timing of Selenium depend on age, gender and overall health condition. The recommended dietary allowance (RDA) for children aged between 1 and 3 years is 20 micrograms per day.

Children aged 4 to 8 years should not exceed 30 micrograms in a day. Those aged 9 to 13 should take up to 40 micrograms. Teenagers and adults are recommended to consume a maximum of 55 micrograms of Selenium per day. If you are pregnant or breastfeeding, don’t exceed 60 and 70 micrograms of Selenium respectively.

However, there are some conditions which can be treated by higher doses of selenium. Studies indicate that consuming 200 micrograms of Selenium every day is effective in preventing prostate cancer.

Uses of Selenium in Supplements

Selenium can be found in many dietary supplements in the market. However, the federal government’s 2010 Dietary Guideline for Americans notes that all nutrients should be primarily obtained from foods. Although food is rich in nutrients and dietary fiber, not everyone has access to all of them.

Thus, a dietary supplement can be advantageous in specific conditions where a person needs to increase intake of a particular mineral like Selenium or vitamins. Always check the label of a dietary supplement to determine the amount of Selenium it contains.

Selenium Interactions

Some medication can trigger a reduction of Selenium levels in your body. On the other hand, Selenium can interact with certain prescription drugs and supplements. These include antacids, corticosteroids, chemotherapy medications, birth control pills, niacin, and cholesterol-lowering drugs.

It is, therefore, important to discuss your Selenium status with a medical professional before trying supplements with this mineral. In addition, don’t stop using prescribed medication if you want to switch to Selenium supplements without first consulting with your doctor.


Selenium is an important mineral that facilitate normal cellular functions in the body. It is only required in trace amounts and can be readily obtained in most regular food. Its availability in the soil varies depending on location and condition.

Studies have shown that consuming certain amounts of Selenium every day can ward off a number of health problems. This makes it an important ingredient to look for in any supplement. However, limit your Selenium intake to the recommended doses as an overdose can cause adverse reactions or even death.

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