Selenium is an important trace mineral. It should be included in adequate amounts in the best diet plan, especially for people with pre-diabetes metabolic syndrome, in order to avoid full type 2 diabetes and its many nasty complications, including foot ulcers that place patients at risk for amputation.
A “trace mineral” is a mineral that is required by your body in relatively small amounts. That does not mean it is not important. To the contrary, we require selenium for the function of many enzymes that keep our body humming right along.
Selenium is important for the development of the tough outer coating of the skin and nails, called keratin. This is a protein made by special cells called keratinocytes. In light of this, researchers looked at the association between the amount of selenium found in the toenails of 3,630 women in the Nurses’ Health Study, and 3,535 men in the Health Professionals Follow-Up Study to see if there was an association between the amount of toenail selenium and type 2 diabetes.
They found out that people with higher toenail selenium levels are at lower risk for type 2 diabetes. This implies that inadequate selenium may be a factor in the development of type 2 diabetes.
As a matter of fact, in people with a diet containing adequate selenium, the risk of developing type 2 diabetes was reduced by as much as 24%.
For both men and women, the researchers found the risk of developing diabetes was 24% lower among the health care workers if they were among the top 20% of toenail selenium content, compared to people who had the lowest 20% of selenium in their toenails.
Given that selenium is required in only small (“trace”) amounts, supplementation is not usually needed. Some multivitamins will contain some trace elements, including selenium.
Foods with higher selenium content include fish, chicken and beef. The regular readers of Nutrientology are especially interested in a diet that favors healthy blood sugar levels along with healthy fats and cholesterol levels. They are therefore eating some meat protein (mostly fish and chicken with occasional red meat) and getting adequate selenium in their diet. If your diet contains meat products, your selenium level should be okay – More justification for the “Ancestral Diet” approach to eating.
The Institute of Medicine recommends adults get 55 mcg of selenium daily.
Although rare, there is such a thing as selenium toxicity. It is advised that adults not take in more than 400 mcg/day to avoid side effects from selenium build-up in the body.
High levels of selenium can lead to chronically high selenium levels known as selenosis with symptoms of stomach problems, hair loss and mild nerve damage.
Sounds kind of odd to me, but Brazil nuts in particular are especially high in selenium – more than 500 mcg of selenium per ounce! Isn’t nature interesting? The Office of Dietary Supplements at the National Institute of Health advises that one eat Brazil nuts only occasionally, and not too many at once.
The smart readers of Nutrientology understand that when it comes to nutrients and nutrition one can have “too much of a good thing.” A healthy body exists in metabolic balance. The body has ways of managing excesses up to a point. Some nutrients have a bigger “metabolic margin of error” than others. In other words, the body has the ability to process a wider concentration of some nutrients, and a very narrow range of others, before disease can set in. I have posted about the excess intake of vitamin D and its possible negative effects on longevity.
In some places, selenium occurs in low concentrations in the soil, affecting the selenium content of foods grown in the region, and therefore the people who live in the area. China and Russia are known for having soils with low selenium content.
Selenium levels in the U.S. population as a whole are okay because of high selenium content of soils in some parts of the country, and the transport of food outside these areas to other parts of the U.S..
For more information on selenium, the National Institutes of Health Office of Dietary Supplements has a good selenium fact sheet available.