Enthusiastic users of dietary supplements—people who use more than one—have a new favorite, according to the results of a recent survey by ConsumerLab.com, an independent lab that tests supplements. This year, fish oil/omega-3 supplements surpassed multivitamins in popularity; the most-wanted list also included calcium, vitamin D, probiotics, flaxseed oil, and amino acids. U.S. News has written about many of those supplements before. [Read Fish Oil Supplements, EPA, DHA, and ALA: Does Your Omega-3 Source Matter?, How Much Vitamin D Should You Be Taking? and Some Bacteria for Brunch.] But we haven't reported much on two notable items on the list: Coenzyme Q10 (CoQ10), the third most popular supplement, with 55 percent of respondents reporting its use; and resveratrol. The latter was used by 19.4 percent of respondents, but it was a big mover, with a 66 percent increase over the last year. So here's the skinny on these two increasingly popular supplements:
CoQ10 occurs naturally in the body, notably, in the mitochondria, which you may remember your high school biology teacher referring to as "the energy factories of the cells." CoQ10 contributes to that energy production process and can act as an antioxidant. Though your body makes its own, in some cases—including in people with heart failure and some neurodegenerative disorders—levels decrease below normal. CoQ10 levels also decline with age. And some medications, most commonly the statins taken by millions of Americans for high cholesterol, "impair CoQ10 synthesis as an inevitable side effect of their mechanism of action," according to a ConsumerLab.com review of the supplement.
You can see where this is going: If levels are low, perhaps CoQ10 supplementation might improve health or function. There is some evidence that supplementing with CoQ10 helps congestive heart failure patients, although not all the trials have showed a benefit. (An ongoing trial is specifically looking at whether CoQ10 supplementation improves survival in heart failure patients.) If you do have heart failure and wonder if CoQ10 is for you (in conjunction with, not as a replacement for, other treatments), talk to your doctor so he or she can review the evidence with you more thoroughly.
Some doctors may also suggest using CoQ10 if you're taking a statin drug to cut down on the muscle aches that plague some users. There are no large, definitive studies that settle the question of whether this is effective. Mary Beth Augustine, a registered dietitian and senior integrative nutritionist for Beth Israel Continuum Center for Health and Healing in New York, says she may include CoQ10 as part of a short-term therapeutic regimen for folks on statins. While CoQ10 appears to be safe in humans, she says she still favors the lowest dose that seems to bring results—starting at, say, 100 milligrams.
But there's no evidence, says Augustine, that CoQ10 is useful for overall wellness purposes in healthy people, and she doesn't recommend its use in that long-term, general context. A study published in 2006 in Free Radical Biology and Medicine set out to determine whether CoQ10 could reduce oxidative stress and aging in mice. The results: While CoQ10 supplementation did increase levels of the substance, it didn't affect oxidative stress and had "no impact on the life span of mice." Another mouse study, published last fall in the Journal of Nutrition, found that low levels of CoQ10 didn't seem to have an effect on cognitive and motor functions, while high levels actually exacerbated the cognitive and sensory impairments seen in elderly rodents. (In other words, they had even more trouble finding their cheese.)
Of course, people aren't mice, and many people are flocking to the supplement because of the perception it will give them more energy and fight the ravages of aging, says Tod Cooperman, ConsumerLab.com's president (and an M.D.). He says there's now another supplement being sold, called ubiquinol, which is the form of CoQ10 actually utilized by the body. Whether either provides the clinical benefits for which people are buying them is an open question.