Findings from a randomized, double-blind, placebo-controlled trial, published on April 17, 2021 in the journal Nutrients, revealed a reduction in D-dimer levels among older Swedish men and women who received selenium and coenzyme Q10 (CoQ10), as well as a lower risk of mortality from cardiovascular disease in individuals having higher D-dimer levels at baseline.

Coenzyme Q10 is an antioxidant involved in the mitochondria’s production of energy. It has been estimated that the body’s production of CoQ10 at the age of 80 years is approximately half that of someone who is 20 years old.

Selenium is a trace element necessary for normal function of human cells. Dietary intake of this mineral may be insufficient in areas of the world that have low soil selenium levels. Selenium also is necessary for the function of many antioxidant enzymes, including one which recycles CoQ10, and has anti-inflammatory activity.

D-dimer is a fragment of degraded fibrin and is commonly used to assess for the presence or degradation of potentially dangerous blood clots (venous thromboembolism or pulmonary embolism). It also reflects the activity of peripheral artery disease and has been shown to be associated with endothelial dysfunction and inflammation even in the absence of thromboembolism.

The current investigation included 213 men and women aged 70 to 88 years who did not have conditions known to influence D-dimer concentrations (e.g., atrial fibrillation, malignancies). Participants received a placebo or 200 micrograms selenium plus 200 milligrams CoQ10 daily for four years.

Blood samples collected from the subjects upon enrollment in the trial and at 48 months were analyzed for levels of D-dimer. Although D-dimer levels were not significantly different between groups at the beginning of the trial, it was noted to be significantly associated with age. At 48 months, a significantly lower level of D-dimer was found among those who received selenium and CoQ10 in comparison with the placebo, which was maintained after adjustment for co-variates that might influence D-dimer (such as C-reactive protein).

When participants with D-dimer levels that were above the median of all participants at baseline were analyzed, an association was found between intake of selenium and CoQ10 and a lower risk of cardiovascular mortality. Among those whose D-dimer levels were higher than 0.21 mg/L at the beginning of the study, one person among 53 who received selenium and CoQ10 died during a median 4.9-year follow-up period compared to 8 of the 52 who received a placebo. Mortality from all causes was also lower in the selenium and CoQ10 group; however, the reduction failed to reach statistical significance.

This group also reported a larger study, which didn’t exclude individuals having conditions known to increase D-dimer, finding that in the older Swedish citizens the combination of selenium and CoQ10 significantly increased heart systolic function, lowered NT-proBNP (which is elevated during heart failure) and decreased risk of cardiovascular mortality, defined as death from myocardial infarctions, cerebrovascular lesions, cardiac arrythmias, heart failure or aortic aneurysms.¹

“[Intake of] selenium and coenzyme Q10 in a group of elderly low in selenium and coenzyme Q10 prevented an increase in D-dimer and reduced the risk of cardiovascular mortality in comparison with the placebo group,” concluded first author Urban Alehagen and his colleagues. “The obtained results also illustrate important associations between inflammation, endothelial function and cardiovascular risk.”

1. Alehagen U et al. Int J Cardiol. 2013 Sep 1;167(5):1860-6.