November 15, 2009
High Selenium Boosts Blood Cholesterol?

Too much selenium probably boosts blood cholesterol.

A new study from the University of Warwick has discovered taking too much of the essential mineral selenium in your diet can increase your cholesterol by almost 10%.

Selenium is a trace essential mineral with anti-oxidant properties. The body naturally absorbs selenium from foods such as vegetables, meat and seafood. However, when the balance is altered and the body absorbs too much selenium, such as through taking selenium supplements, it can have adverse affects.  

A team led by Dr Saverio Stranges at the University's Warwick Medical School has found high levels of selenium are associated with increased cholesterol, which can cause heart disease. 

In a paper recently published in the Journal of Nutrition, the research team examined the association of plasma selenium concentrations (levels of selenium in the blood) with blood lipids (fats in the blood). 

The researchers found in those participants with higher plasma selenium (more than 1.20 µmol/L) there was an average total cholesterol level increase of 8% (0.39 mmol/L (i.e. 15.1 mg/dL). Researchers also noted a 10% increase in non-HDL cholesterol levels (lipoproteins within your total cholesterol that can help predict the risk of someone suffering a heart attack or chest pain). Also, of the participants with the highest selenium levels, 48.2% admitted they regularly took dietary supplements. 

It is not easy to choose an optimal diet.

This reminds me of a study that illustrates the potential for genetic testing to optimize diet choices (nutrigenomics): Whether selenium helps or hurts against prostate cancer risk depends on which genetic variant you have for the enzyme manganese superoxide dismutase (SOD2). So Brazil nuts probably cut prostate cancer risk in some while boosting risk for others.

Higher selenium levels in the blood may worsen prostate cancer in some men who already have the disease, according to a study by researchers at Dana-Farber Cancer Institute the University of California, San Francisco.

A higher risk of more aggressive prostate cancer was seen in men with a certain genetic variant found in about 75 percent of the prostate cancer patients in the study. In those subjects, having a high level of selenium in the blood was associated with a two-fold greater risk of poorer outcomes than men with the lowest amounts of selenium.

By contrast, the 25 percent of men with a different variant of the same gene and who had high selenium levels were at 40 percent lower risk of aggressive disease. The variants are slightly different forms of a gene that instructs cells to make manganese superoxide dismutase (SOD2), an enzyme that protects the body against harmful oxygen compounds.

You can imagine how two different studies on selenium and prostate cancer could come to opposite conclusions if their patient groups had different distributions of SOD2 variants.

If you are a guy and can find a genetic testing service that will test for SOD2 variants you could find out whether you should eat high selenium foods or avoid them. I wonder whether these SOD2 variants modify the risks for other diseases.

Share |      Randall Parker, 2009 November 15 09:39 PM  Aging Diet Heart Studies

DensityDuck said at November 16, 2009 2:47 PM:

Also, don't forget that selenium attracts paranormal energy.

Beth Donovan said at November 16, 2009 3:02 PM:

That selenium can have a negative effect on health is no surprise to horse owners and goatherds. Too much selenium can kill a horse, and in short order( Too little selenium in goats can cause something called white muscle disease - which can also be fatal. (

Trace mineral supplements can be so very dangerous for herd animals, it only makes sense they can be detrimental to humans, too.

Greg F said at November 16, 2009 4:36 PM:


First law of toxicology is it's the dose that makes the poison. Even water in a large enough dose can be toxic.

Typically, substances are classified by their LD50 (lethal dose that kills 50% of the population). Table salt has a LD50 of 3 gm/kg for rats and a LDLO (lowest published lethal dose) for humans of 1 gm/kg. For a 50 kg (110 lb) person LDLO would be exceeded with less than 3 tablespoons of salt.

Joe said at November 16, 2009 5:38 PM:

Does selenium boost cholesterol or cholesterol boost selenium? Or is there a third factor that boosts both?

Bob Badour said at November 16, 2009 6:15 PM:

Or does selenium prevent lipid peroxidization leaving more lipids in the bloodstream for the liver to deal with and fewer lipids in arterial foam cells and plaques?

The article references non-HDL cholesterol. Is that the LDL? Or is that something else?

Wolf-Dog said at November 16, 2009 6:46 PM:

It is known that too much Selenium can cause insulin resistance, which is a serious problem. More than 200 micrograms per day would be too much, but the total dosage also depends on how much mercury and other heavy metals you have ingested. Selenium bonds with mercury and actually neutralizes it, dramatically reducing mercury poisoning, but this process causes a selenium shortage in the body, meaning that those who eat too much fish should have more selenium. Thus the dosage of selenium depends on in which country you live and also your exposure level to mercury.

this said at August 28, 2013 5:44 PM:

Selenium is safe, very hard for it to do any harm!

Post a comment
Name (not anon or anonymous):
Email Address:
Remember info?

Go Read More Posts On FuturePundit
Site Traffic Info
The contents of this site are copyright ©