First off, a few definitions:
Coenzyme Q10 is an essential bio-nutrient with vitamin-like properties. It is not considered a vitamin because our cells do synthesize Coenzyme Q10. However, once we reach adulthood, our bio-synthesis of Coenzyme Q10 begins to decline with increasing age [Kalén 1989]. Furthermore, statin medications are known to inhibit the bio-synthesis of Coenzyme Q10 [Okuyama 2015]. Supplementation is a must.
Oxidative stress is the result of an imbalance between the body’s production of harmful Free radicals are unstable and highly reactive molecules that are produced in the body during normal oxygen metabolism. Free radicals derived from oxygen are known as reactive oxygen species. Free radicals play both helpful and harmful roles in the body. Free radicals steal electrons from other substances in order to become stable. In so doing, the free radicals oxidize those... Read more about this term as a by-product of metabolic processes and the body’s supply of antioxidants to neutralize the free radicals. Oxidative stress, unchecked, results in damage to The cell membranes, sometimes called plasma membranes, are the physical barrier that protects the contents of the cells from everything that is outside the cells. The cell membranes also regulate what can move in and out of the cells. Coenzyme Q10 is present in all cell membranes in the body except in the red blood cells. It helps to prevent... Read more about this term, proteins, lipids, and DNA.
A meta-analysis is a form of statistical analysis that evaluates aggregated data from several studies that have addressed the same research question. On q10facts.com, we are especially interested in meta-analyses of randomized, double-blinded, placebo-controlled studies or crossover, double-blinded studies.
The Meta-analysis Search Strategy: CoQ10 and Oxidative Stress
For a 2020 meta-analysis of the effect of CoQ10 supplementation on bio-markers of oxidative stress, researchers searched a variety of databases including PubMed, ISI Web of Science, and Google Scholar [Sangsefidi 2020].
Their search strategy was designed to find bio-medical journal articles that focused on Coenzyme Q10 AND oxidative stress. In their search, the researchers used numerous synonyms for both search terms, e.g. ubiquinone and ubiquinol as synonyms for Coenzyme Q10 and malondialdehyde and thiobarbituric acid-reactive substances and total Antioxidants are substances that protect the cells and lipoproteins against the harmful effects of free radicals. They are substances that prevent the oxidation of other molecules and compounds. There are two broad categories of antioxidants: enzymatic and non-enzymatic. Non-enzymatic antioxidants are substances like Coenzyme Q10, vitamin C, vitamin E, glutathione, and various carotenoids. Prominent enzymatic antioxidants include catalase, glutathione peroxidase,... Read more about this term capacity as synonyms for oxidative stress.
In the addition to investigating the relationship between CoQ10 supplementation and bio-markers of oxidative stress, the retrieved journal articles had to have the following characteristics:
- had to report the dosage of CoQ10 used
- had to enroll study participants aged 18 years or older
- had to report on studies with a duration of 28 days or more
- had to present adequate description of the tested bio-markers for oxidative stress
Initially, the literature search retrieved 6,308 studies. The researchers excluded 6,287 studies for two reasons:
- because the articles did not report clinical trials (n=6,052)
- because the articles did not meet the inclusion criteria (n=235).
In the end, 21 studies published between 1997 and 2019 were included in the meta-analysis. These 21 studies enrolled 1,170 study participants, 614 participants in the intervention groups and 556 in the placebo groups.
All of the studies were parallel studies except for one crossover-design study.
The Meta-analysis Results: CoQ10 and Oxidative Stress
***Meta-analysis of eight of the 21 studies (intervention: n=241; placebo: n=240) showed a The outcome of a clinical trial is thought to have statistical significance, or to be statistically significant, if the outcome is likely not caused by chance at a given statistical significance level, typically at the 0.05 level. Statistically significant outcomes may or may not be clinically significant. ... Read more about this term increase in total antioxidant capacity associated with the CoQ10 supplementation. Total antioxidant capacity is a measure of the antioxidant status of biological samples that can be used to evaluate the antioxidant response to the free radicals produced by a given disease or health condition [Sangsefidi 2020].
***Meta-analysis of 14 of the 21 studies (intervention: n=361; placebo: n=354) showed a significant decrease in the levels of malondialdehyde associated with the CoQ10 supplementation. Malondialdehyde is a known bio-marker for oxidative damage [Sangsefidi 2020].
***Meta-analysis of five of the 21 studies (intervention: n=122; placebo: n=109) showed a significant increase in glutathione peroxidase levels associated with the CoQ10 supplementation. The glutathione peroxidases are selenoprotein enzymes that protect cells against oxidative damage by reducing lipid hydroperoxides to alcohols and by reducing hydrogen peroxide to water [Sangsefidi 2020].
***Meta-analysis of six of the 21 studies (intervention: n=148; placebo: n=136) showed a significant increase in the levels of the antioxidant enzyme superoxide dismutase associated with the CoQ10 supplementation. Superoxide dismutase is an enzyme that neutralizes the harmful superoxide radical by converting it to oxygen and hydrogen peroxide [Sangsefidi 2020].
***Meta-analysis of five of the 21 studies (intervention: n=132; placebo: n=119) showed a significant increase in the levels of the antioxidant enzyme catalase associated with the CoQ10 supplementation. Catalase is an enzyme that facilitates the decomposition of decomposition of hydrogen peroxide to water and oxygen [Sangsefidi 2020].
Discussion of the Meta-analysis Results: CoQ10 and Oxidative Stress
The authors of the 2020 meta-analysis point out that a number of earlier meta-analyses of clinical studies have shown a protective effect of CoQ10 supplementation:
- Decreased levels of bio-markers for Inflammation is an immune system response to an injury to cells or tissues. It is the body’s attempt to defend against invaders such as bacteria andviruses and to mend the damage done by invaders. Typically, inflammation manifests itself in the form of fever and swelling, in the swarming of white blood cells and the release of cytokines to fight against... Read more about this term
- Improved glycemic indices
- Improved lipid profiles
- Reduced blood pressure
The extent of the protection has varied according to the dosage, the duration of the study, the formulation of the CoQ10 supplement, and the health condition of the study participants [Sangsefidi 2020].
Take-Home Message: CoQ10 Supplementation
- Coenzyme Q10 itself, the only endogenously bio-synthesized lipid-soluble antioxidant, plays an important role in inhibiting the production of harmful free radicals.
- Supplementation with Coenzyme Q10 can lead to reduced levels of malondialdehyde, a bio-marker of oxidative stress.
- The activity of the antioxidant enzymes glutathione peroxidase, superoxide dismutase, and catalase increases following supplementation with Coenzyme Q10.
- Supplementation with Coenzyme Q10 increases total antioxidant capacity.
Nota bene: Not all CoQ10 supplements are equally well absorbed. It is important to buy a CoQ10 supplement with documented absorption and bioavailability.
- The formulation of the CoQ10 supplement is much more important to the absorption and bioavailability than the form is.
- A well-formulated ubiquinone CoQ10 supplement will give a significant increase in plasma and lipoprotein ubiquinol levels.
Kalén A, Appelkvist EL, Dallner G. Age-related changes in the lipid compositions of rat and human tissues. Lipids. 1989;24(7):579-584.
Okuyama H, Langsjoen PH, Hamazaki T, et al. Statins are a class of medications that effectively block the body’s synthesis of cholesterol. In so doing, statins also block the body’s synthesis of Coenzyme Q10.... Read more about this term stimulate Atherosclerosis is the thickening of the artery walls brought about by the build-up of plaque (plaque is made up of cholesterol and other fatty substances and waste products and calcium and fibrin) and the subsequent slowing of the flow of blood through the clogged arteries. More research is needed into the role of Coenzyme Q10 in the prevention and adjunct... Read more about this term and The Mayo Clinic defines heart failure, also known as congestive heart failure and/or chronic heart failure, as the failure of the heart muscle to pump blood to the body adequately. In other words, heart failure is not a heart attack, and it is not death from heart disease, which its name might seem to imply. Heart failure is a condition... Read more about this term:
pharmacological mechanisms. Expert Rev Clin Pharmacol. 2015;8(2):189-199.
Sangsefidi ZS, Yaghoubi F, Hajiahmadi S, Hosseinzadeh M. The effect of Coenzyme Q10 supplementation on oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials. Food Sci Nutr. 2020; 8(4): 1766-1776.
The information presented in this review article is not intended as medical advice and should not be used as such.
30 October 2020Please click here for more information about Coenzyme Q10 supplements.