Are There Dangers to Taking Selenium for Psoriasis?

By Kelly Bryant
Reviewed by Allison Truong, M.D.
July 28, 2021

There are 15 minerals found in the body that are considered essential to its optimal performance. These are divided between two groups: macrominerals—those that we need in large amounts; and, trace minerals—those that we need in smaller quantities. Selenium is a trace mineral, which is why we may not hear about it as much as macrominerals like calcium; but, that doesn’t mean it doesn’t serve an important purpose.

Selenium is one of those supplements that people with psoriatic conditions commonly ask about. Here, Elizabeth DeRobertis, a New York-based registered dietitian, weighs in on selenium’s function and its connection to psoriasis and psoriatic arthritis, as well as why you should approach supplements with extreme caution.

Why do our bodies need selenium—what’s its function?

Selenium is an essential mineral, meaning it must be obtained through diet, since our bodies don’t produce it. Selenium is important for reproduction, metabolism, thyroid function, and to protect the body from infection and from damage caused by free radicals. Selenium is an essential component of selenoproteins, which help to make DNA.

What’s the connection between psoriatic disease and selenium?

Although there are not many studies on selenium and psoriasis, it does seem that selenium levels tend to be lower in people with psoriasis and psoriatic arthritis. In a recent study where 87 people with psoriasis were compared to 60 people without psoriasis, certain trace elements including selenium, zinc, and albumin were found to be lower in the psoriasis group.

Because psoriasis is an inflammatory skin disease, it makes sense to examine deficiencies in any nutrients that are related to the immune system. Selenium can actually influence the body's immune response by changing the expression of cytokines (proteins used to send signals throughout the body) and their receptors. This can make immune cells more resistant to oxidative stress.

Selenium supplementation has been studied in people with psoriasis, but the results have varied, so more research is needed. At this point, there’s no clear evidence that taking selenium supplements leads to improved psoriatic symptoms.

If my doctor and I decide I should take selenium, how much should I take? And is there anything else I need to know before taking it?

The window between the recommended amount of selenium and a potentially harmful amount of selenium is small, according to researchers. So, supplementation may be beneficial for people with low selenium, but could be harmful for those with normal or high selenium intake.

Antioxidants that fight inflammation and free-radical damage in the body work best when there is selenium present. The recommended dietary allowance (RDA) for adult men and women is 55 micrograms daily. Women who are pregnant and lactating need about 60 and 70 micrograms daily, respectively.

The Tolerable Upper Intake Level (UL) for selenium for all adults (including pregnant and lactating women) is 400 micrograms daily, meaning that taking more than that amount daily could have harmful effects on health.

There is some research that points to the idea that selenium taken in combination with thyroid medication may help to lower autoimmune thyroid antibodies.

Are there any potential negative side effects of taking a selenium supplement?

Yes, high intakes of selenium can lead to health problems. Potential side effects include muscle tremors, hair loss, nail changes, stomach upset (including nausea, vomiting, diarrhea), vision changes, and lightheadedness. More severe potential side effects include heart attack, respiratory distress, impaired endocrine function, neurotoxicity, or kidney failure.

People with psoriasis should know that for anyone already diagnosed with autoimmune disease, it is not a good idea to take too much selenium as it may have immunostimulant effects. This means it could worsen an autoimmune disease by stimulating disease activity.

Which foods are rich in selenium?

Foods with the most selenium include pork, beef, turkey, chicken, fish, shellfish, and eggs. A 6-ounce chicken breast provides almost 100 percent of the recommended daily value of selenium. A 6-ounce pork chop provides 147 percent of the daily value, while 6 ounces of yellowfin tuna provides 334 percent of the daily value. Breads, cereals, and other grain products are also rich in selenium.

Brazil nuts provide the absolute highest amount of selenium. One nut contains 95 micrograms of selenium, which is almost double the RDA. Eating too many of these nuts on a daily basis can reach a toxic level.

As you can see, it’s pretty easy to incorporate selenium into your diet, and it’s possible to overdo it, so most people don’t need to take supplements.

What changes might a person with psoriasis and/or psoriatic arthritis notice by taking selenium, if they’ve found they’re deficient in it?

Some symptoms of selenium deficiency include fatigue, mental fog, hair loss, muscle weakness, a weakened immune system, infertility, and cardiomyopathy. Selenium deficiency can also cause Kashin-Beck disease, which is a type of arthritis that produces pain, swelling, and loss of motion in the joints. This disease was seen in children and females of childbearing age in areas of China where local diets were devoid of selenium. If someone is deficient in selenium and experiencing any of these symptoms, it should improve when they increase their intake of selenium.

What if the person is not deficient in selenium? Should they take supplements?

If someone takes a supplement without being deficient in that nutrient, it increases their chance of toxicity. With certain supplements—like vitamin B, which is water-soluble—this is less worrisome, because any excess will be excreted from the body through urine. However, there are a number of substances that can accumulate in your system and reach toxic levels; selenium is one of them.

It’s important to consult your healthcare provider before starting any supplements. If you’re not deficient in selenium, not only will you not see benefits when taking selenium supplements, but you’ll also be putting your health at risk.

Also, since there are no studies that show selenium supplementation improves psoriasis, it’s best to first start with treatments that are known to benefit psoriasis.

You May Also Like: