Can Taking Selenium Influence Lipid Levels?

selenium
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Selenium is a trace element that is categorized as a micronutrient, meaning that you only need small amounts to get what your body needs. Selenium can be found in the environment, in places such as water and soil. It can also be found in various supplements and in some foods - including meat, mushrooms, seafood, nuts and grains. Selenium is also classified as an essential nutrient, meaning that it must be obtained from the foods we eat in order to incorporate it into our bodies.

Selenium works with antioxidant enzymes in the body that participate in cellular growth. Some studies have found that selenium may help to protect against certain cancers, chronic medical conditions, and boost your immune system. A few other studies have indicated that too much or too little selenium may affect your heart health, and cause certain aspects of your lipid profile to become increased.

How Does Selenium Affect Cholesterol?

Only a few studies have been conducted that examine the effects of selenium on cholesterol and triglyceride levels. These studies measure “selenium status”, which refers to the concentration of selenium in your blood. This can vary widely according to a variety of factors, but mostly from supplements containing selenium or your food intake.

Selenium status also varies widely according to regions of the world. For instance, people living in the United States and Canada have a high selenium status, whereas Europeans have a lower selenium status.

High and low selenium statuses are seen in people living in China. Previous studies have shown that individuals having a low selenium status are at a higher risk of cardiovascular disease. On the other hand, having high selenium levels may cause your lipid levels to become too high - especially if you already have higher selenium concentrations in your blood.

In some of these studies, people with a high selenium status had elevated total cholesterol levels and LDL cholesterol levels. Total cholesterol levels were increased by up to 8 percent and non-HDL cholesterol was increased by about 10 percent. Additionally, triglycerides were also increased by up to 10 percent in comparison to people who had a lower selenium status. However, another study suggested a U-shaped relationship between selenium levels and triglycerides - that is, individuals with high and low selenium status also had higher triglyceride levels.

In one study, it was noted that individuals with a low selenium status taking a selenium supplement ranging between 100 and 200 mcg) saw modestly lowered total cholesterol and non-HDL cholesterol levels. In this same group, taking 300 mcg of selenium resulted in slightly increased HDL levels, but did not affect other lipid levels. 

On the other hand, there are other studies that do not show a relationship between selenium and lipid levels.

It is not exactly known how selenium can affect lipids. One thought is that selenium can combine with certain proteins in the body that interact with lipids and lipoproteins. It is also thought that selenium may help to prevent the development of oxidized lipoproteins, which can promote the formation of atherosclerosis. 

Should I Take Selenium for Healthy Lipid Levels?

Despite some of the results seen so far, more studies are needed to examine the effects of selenium on lipids and heart health, since this appears to vary widely depending on your selenium levels. Therefore, selenium supplements should not be taken to lower your lipids. Selenium can be toxic at high concentrations, and should not be taken as a supplement unless directed by your healthcare provider. Because selenium is often obtained in foods and is needed in small amounts, following a healthy, well-balanced diet should ensure that you are obtaining this important nutrient.  

Sources:

Bleys J, Navas-Acien A, Stranges S et al. Serum selenium and serum lipids in US adults. Am J Clin Nutr 2008; 88: 416-423.

Laclaustra M, Stranges S, Navas-Acien A et al. Selenium status and serum lipids in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2004. Atherosclerosis 2010; 210: 643-648.

Rayman MP. Selenium and human health. Lancet 2012; 379: 1256-1268.

Rayman MP, Stranges, S, Griffin BA et a, Ann Int Med 2011; 154: 656-665.

Stranges S, Tabak AG, Guallar E, et al.  Selenium status and blood lipids: the cardiovascular risk in young finns study. J Int Med 2011; 270: 469-477.

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