A selenium deficiency can result in low energy levels, poor mental performance, impaired immune function, goiter, muscle weakness and fertility problems.
Individuals who have too little selenium in the body are also at risk of Keshan disease affecting the heart or Kashin-Beck disease resulting in arthritis-like symptoms and loss of joint mobility.
Selenium deficiencies are very rare in North American. But even in cases where a deficiency does not exist, low levels of this mineral in the diet can cause other health problems.
What are the symptoms of not having enough selenium in your diet and what are the best sources to increase your intake? This article will discuss the effects of low levels on the body and recommend food sources and supplements to boost selenium status.



- Cofactor for antioxidant enzymes
- Supports thyroid function & metabolism
- Promotes immune function & fertility
Selenium Deficiency
Selenium occurs in trace amounts in nature. Plants gain this mineral from the soil. Even in some countries where the soil lacks selenium (Se), diagnosed deficiencies are rare.
Small amounts of selenium are needed for maintaining human health. The US RDA (Recommended Dietary Allowance) for selenium is 55 mcg/day for healthy people over 14 years of age.
When deficiencies do occur, symptoms including hair loss, fatigue and weakened immunity may result. According to the National Institutes of Health (NIH), groups most likely to develop deficiency are:
- People living in areas where the soil is low in this mineral;
- People undergoing kidney dialysis;
- People with HIV/AIDS;
In the US, the average daily intake of dietary sources ranges between 100 mcg and 250 mcg daily. Comparatively, in Finland and New Zealand, the average daily intake is between 30 mcg and 50 mcg.
In some regions in China, the daily intake is less than 15 mcg on average. When selenium intake is this low, a congestive heart muscle disorder called Keshan disease often develops.
This viral disease is potentially fatal but can most often be avoided with daily intake of at least 20 mcg. [1]
Low levels of this mineral is associated with a type of osteoarthritis called Kashin-Beck disease that can result in swelling and pain in the joins. This condition is most prevalent in Tibet, China and Siberia. [2]
Selenium is required for removing iodine (deiodination) from thyroid hormones to produce active triiodothyronine (T3). This thyroid hormone is involved in energy metabolism throughout the body.
Being deficient in selenium can exacerbate iodine deficiency; one of the world’s most common micronutrient deficiencies. Iodine deficiency is the most prevalent preventable cause of mental retardation and cretinism in newborns.
Selenium Deficiency Symptoms
Keshan disease, Kashin-Beck disease and mental retardation/cretinism due to iodine deficiency are extreme examples of selenium deficiency symptoms.
However, there are some less serious symptoms possible as well in people who do not get enough of this mineral from the diet.
Some of these signs of low selenium status include:
1. Hair loss (alopecia):
Deficiency can cause hair loss and inhibit hair regrowth. Normally, loss of head hair due to low selenium occurs rapidly and with even distribution. In the worst cases, hair loss may also occur under the arms and in other body areas.
2. Skin and nail health:
Chronically low selenium levels can cause discoloration of the skin, fingernails and toenails. In some cases, the beds of the nails become whitened.
3. Weakened immunity:
Selenium is a constituent of an important antioxidant enzyme called glutathione peroxidase. Lacking this mineral in the diet can cause inadequate production of this substance, making it more difficult for you body to fight off viral and bacterial infections.
4. Chronic fatigue/tiredness:
Selenium deficiency is one of various possible reasons for chronic fatigue and tiredness. Diminished energy production can also result from vitamin B5 (pantothenic acid) deficiency or an iron deficiency.
If you believe your consistent fatigue may be due to a micronutrient deficiency, then consider having a blood test ordered by your doctor.
5. Brain fog:
Poor concentration and brain fog are common symptoms of deficiency. Some people also experience difficulties recalling previously learned information. Some people claim that increasing selenium intake helps them with irritability, depression and anxiety as well.
6. Reproductive health:
Selenium is important for reproductive health. Low levels have been associated with male infertility in some preliminary studies. Deficiency can cause harm to sperm cells; decreasing their motility (locomotion). Reduced motility leads to reduced fertility.
Insufficient selenium levels can also cause alterations in menstruation cycles for some women. Some studies suggest that not having enough of this mineral may also be a cause of recurrent miscarriage.
7. Hypothyroidism:
Having low selenium levels for too long can cause dysfunction of the thyroid gland. This can cause hypothyroidism; a condition where the thyroid gland is underactive. Hypothyroidism hinders healthy growth and development in both children and adults.
When the thyroid is underactive, it fails to produce adequate amounts of T3 (triiodothyronine) and T4 (thyroxine) hormones. This type of hormonal imbalance commonly results in symptoms including depression, fatigue and weight gain, among others. [3]
Getting Tested for Selenium Deficiency
If you believe you may be deficient in selenium, then you should consider having a doctor test your levels. Healthy plasma levels range between 8 and 25 mcg/dL depending on the amounts commonly obtained via diet.
Selenium levels can be tested in blood and hair samples. Note that blood samples only show how much of a nutrient you have ingested recently.
Also, hair tests are known to be inconsistent and inaccurate. This is because selenium is stored in different concentrations in different cell types throughout the body.
In most cases, this essential trace mineral can be gained in adequate amounts solely from foods ingested. In rare cases, supplementation may be necessary to reduce deficiencies.
Rich Food Sources
The body only needs small amounts of this mineral to function normally. For most people, getting enough selenium from foods is not a problem. However, if you need to increase your intake of this compound, consider the following food sources.
Brazil nuts are the most concentrated food source of selenium. One ounce of dried Brazil nuts contains more than 500 mcg of selenium; more than 900% the RDA.
Some other good sources include beef and fowl liver, muscle meats, certain fish and shellfish, dairy products and eggs. Various plant foods also contain high amounts of this mineral. Some of these include:
- Green leafy vegetables like spinach, cabbage and kale;
- Nuts like walnuts, almonds and pistachios;
- Beans like pinto, lima and kidney;
- Seeds like chia, sunflower and flax;
Selenium is also found in good amounts in various herbs. Some of these include ginger, turmeric, ginseng, garlic and fenugreek. Others include chamomile, burdock root, peppermint, lemongrass and rose hips.
Research shows that selenium supplementation needs to be approached with knowledge and caution. Slight changes in selenium intake can cause either excess or deficiency. [4]
Selenium deficiency can be very serious and lead to ongoing health problems. It is best to seek medical advice before attempting to raise your levels through supplements or foods.
- Institute of Medicine (US) Panel on Dietary Antioxidants and Related Compounds. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington (DC): National Academies Press (US); 2000. Available from: http://www.ncbi.nlm.nih.gov/books/NBK225483/ doi: 10.17226/9810
- Jirong Y1, Huiyun P, Zhongzhe Y, Birong D, Weimin L, Ming Y, Yi S. Sodium selenite for treatment of Kashin-Beck disease in children: a systematic review of randomised controlled trials. Osteoarthritis Cartilage. 2012 Jul;20(7):605-13. doi: 10.1016/j.joca.2012.02.012. Epub 2012 Feb 24.
- Brown KM1, Arthur JR. Selenium, selenoproteins and human health: a review. Public Health Nutr. 2001 Apr;4(2B):593-9.
- Kieliszek M1, B?a?ejak S2. Current Knowledge on the Importance of Selenium in Food for Living Organisms: A Review. Molecules. 2016 May 10;21(5). pii: E609. doi: 10.3390/molecules 21050609.
Article last updated on: July 15th, 2018 by Nootriment