Selenium and heart disease

There have been two noteworthy discoveries from a recent randomized controlled trial conducted by Dr. Urban Alehagen of Linköping University (Sweden) and his colleagues.

Firstly, people with low concentrations of selenium in their blood were found to be at significantly higher risk of death from heart disease.

Secondly, a combination of a patented high selenium yeast supplement and a proven Coenzyme Q10 supplement taken daily for four years provided significant protection against heart disease in people with low serum selenium status.

The KiSel-10 study of cardiovascular mortality
The study enrolled 668 healthy elderly individuals aged 70-80 years.  The study was well-designed and well-executed.  One group of 219 randomly selected individuals received 200 micrograms of selenized yeast tablets and 200 milligrams of Coenzyme Q10 capsules daily for four years. A second randomly assigned group of 222 individuals received matching placebos.  The remaining group of 227 individuals received no treatment at all.

The study participants in the KiSel-10 study of cardiovascular mortality
After the initial four-year period of treatment with the supplement combination or placebo, the researchers followed the study participants for an average of 1870 additional days (slightly more than 5 additional years) beyond the end of the treatment period.  During the follow-up, all instances of death from heart disease were recorded. None of the study participants were lost from the scrutiny of the researchers.

Remember, these were study participants who had a mean age of 77-78 years at the start of the study.  Think how old they were 10 years later.

For purposes of analysis, the researchers divided the study participants into three groups according to their serum selenium levels at baseline:

• Selenium concentrations below 65 nanograms per milliliter (the same as 65 micrograms per liter)
• Selenium concentrations between 65 and 85 nanograms per milliliter
• Selenium concentrations above 85 nanograms per milliliter

The ratio of males to females in the lower two groups was just slightly more than 1:1. The ratio in the highest group was close to 2:1 in favor of males.

Serum selenium concentrations and death from heart disease
Dr. Alehagen and his team compared the rates of death from heart disease in the study participants who did not receive any supplements.  Repeat: these were the study participants who did not receive any supplements, neither active treatment nor placebo.

Among these study participants, those with baseline serum selenium concentrations below 65 nanograms per milliliter had a death from heart disease rate of just over 28%.  In the study participants with baseline serum selenium concentrations above 85 nanograms per milliliter, the death rate was 14%.

That difference is statistically significant.  It is also clinically significant.  I know without hesitation which group I want to belong to.

The effect of selenium supplementation on heart disease
Four years of daily supplementation with the patented selenized yeast raised the serum selenium concentrations in the study participants to levels ranging from 185 to 245 nanograms per milliliter.  The study participants’ serum selenium concentrations rose to those levels regardless of whether they started, at baseline, below 65 nanograms per milliliter or above 85 nanograms per milliliter or in between.  Meanwhile, the serum selenium concentrations of the participants in the placebo group remained the same.  Clearly, the supplementation improved serum selenium status.

Selenium and heart disease in the low group
Among the study participants with the lowest baseline serum selenium concentrations, i.e. below 65 nanograms per milliliter, there was a rate of 24.1% deaths from heart disease among the individuals not given the combination supplementation of high selenium yeast and Coenzyme Q10.

By contrast, the individuals who did receive the supplement combination for four years had a death rate of 12.1%.  The difference in the two death rates is statistically significant.  An absolute reduction of 12% in the death rate is surely clinically significant as well.

Selenium and heart disease in the middle group
In their analysis of the study participants in the middle group, i.e. baseline serum selenium concentrations between 65 and 85 nanograms per milliliter, the researchers found a death rate from heart disease of 14% among the unsupplemented study participants and 6% among the supplemented study participants.  This is also a statistically significant reduction in the death rate.

Selenium and heart disease in the high group
Only in the group of study participants with a baseline serum selenium concentration above 85 nanograms per milliliter was there no statistically significant reduction of the rate of death from heart disease.  But, the researchers caution, the “high” group was the smallest group.

The sample size was small, and the confidence interval was quite wide.  Drawing conclusions from the data from this small sample is perhaps not a good idea.

Selenium intakes and the activity of important selenoproteins
Dr. Alehagen points out that low selenium intakes from the food we eat will result in low serum (or plasma) selenium concentrations that are below the level needed for the optimal expression and functioning of the selenoproteins glutathione peroxidase and selenoprotein P, both of which have important anti-oxidative properties.  Moreover, we need adequate quantities of selenium in the form of thioredoxin reductase because thioredoxin reductase helps to reduce the oxidized form of Coenzyme Q10, ubiquinone, to its anti-oxidative form ubiquinol.

Thus, selenium and Coenzyme Q10 both work to protect the heart muscle tissue against the damage caused by oxidative stress.  Oxidative stress is understood to be the imbalance between harmful free radicals and neutralizing antioxidants in the body.

Summary
What have we learned from Dr. Alehagen’s study that is valuable?

• Healthy elderly individuals are at significantly higher risk of death from heart disease if they have serum selenium concentrations below 85 nanograms per milliliter.
• Daily supplementation with 200 micrograms of an organic high-selenium yeast preparation will raise the serum selenium levels of all individuals to approximately the same levels (185 – 245 nanograms per milliliter) regardless of the baseline serum selenium concentration.
• Daily supplementation with high-selenium yeast and Coenzyme Q10 in combination resulted in substantial reductions in the risk of death from heart disease.

Sources

Alehagen, U., Alexander, J., & Aaseth, J. (2016). Supplementation with Selenium and Coenzyme Q10 Reduces Cardiovascular Mortality in Elderly with Low Selenium Status. A Secondary Analysis of a Randomised Clinical Trial. Plos One, 11(7), e0157541.

Alehagen, U., & Aaseth, J. (2015). Selenium and coenzyme Q10 interrelationship in cardiovascular diseases–A clinician’s point of view. Journal of Trace Elements in Medicine and Biology, 31, 157-162.