Are CoQ10's Benefits for Real?
Many claims are made about CoQ10 benefits. Coenzyme Q10 (CoQ10) is a vitamin-like substance sold as a dietary supplement. Claims include that it may help treat, or possibly prevent
- heart disease
- Parkinson's disease
- certain cancers
- gum disease
- allergies and
- other conditions
CoQ10 is said to boost immunity, enhance athletic performance, aid memory, and slow aging. Nothing can do all that, but since its discovery 50 years ago, research continues to uncover a range of potential CoQ10 benefits.
CoQ10 is also called ubiquinone because it belongs to a class of compounds called quinones, and because it's present everywhere (ubiquitous) in living organisms, especially in the heart, liver, and kidneys. Made by the body, it's essential for energy production in the mitochondria of cells, plus it's a powerful antioxidant. Some foods, notably meat and fish, contain small amounts of CoQ10.
Like many substances in the body, CoQ10 levels decline with age and are lower in people with certain medical conditions, such as Parkinson's disease, some cardiac disorders, and asthma. But that doesn't mean that CoQ10 "deficiency" causes disease or that supplements will treat disease or reverse the effects of aging. Some cholesterol-lowering statin drugs, as well as certain beta blockers and antidepressants, can reduce blood levels of CoQ10, but there's no evidence that this leads to any health problems.
Putting CoQ10 Benefits to the Test
According to the Natural Standard, which evaluates complementary and alternative therapies, there is "unclear scientific evidence" for most uses of CoQ10, and "fair scientific evidence" against its use for diabetes and Huntington's disease. Much of the encouraging research has been in the lab, while human studies have tended to yield inconsistent results.
Here are some uses for CoQ10 that look more promising:
- High blood pressure (hypertension). An analysis of 12 studies of people with hypertension, in the Journal of Human Hypertension in 2007, found that CoQ10 lowered systolic blood pressure 11 to 17 points, and diastolic pressure 8 to 10 points. This may be due to CoQ10's ability to dilate blood vessels. The Natural Standard gives CoQ10 a "B" grade for hypertension, citing "good" evidence for this use but also the need for more studies.
- Heart conditions. People with cardiac disease often have low levels of CoQ10, and cells of the heart are sensitive to reductions in CoQ10. According to a 2010 review in Nutrition, heart failure patients with low CoQ10 have higher death rates. CoQ10 has shown a range of heart benefits, including a reduction in arrhythmias after bypass surgery and improvements in cardiac function indicators in people with heart failure. CoQ10 may benefit the cardiovascular system through its antioxidant and anti-inflammatory effects and by improving blood vessel function. But the Natural Standard says there is not enough evidence to recommend for or against its use in people with coronary heart disease, and that the evidence that CoQ10 helps treat heart failure, in particular, is unclear. Still, CoQ10 is prescribed for certain heart ailments in Japan and several European countries.
- Parkinson's disease. A study from the University of California, San Diego, in the Archives of Neurology in 2002, found that very large doses of CoQ10 appeared to slow the progression of early Parkinson's disease and improved daily life. Though a 2007 study in the same journal did not find a benefit of CoQ10, it included people with more advanced disease and used lower doses for a shorter time. Better-designed studies are needed, but the Natural Standard still calls the overall evidence "promising."
- For statin takers. An uncommon side effect of statin drugs is muscle pain and damage. Since some statins lower blood levels of CoQ10, it's theorized that this is what causes the problem. But while CoQ10 supplements have been shown to raise blood levels of CoQ10, it's unclear if supplements raise CoQ10 levels in muscle. And studies looking at whether supplements actually reduce the risk of muscle problems have had mixed results.
The claims for CoQ10 are overblown, and there's no reason to take the supplement, especially if you are healthy. No one knows how much to take or which formulation, if any, is best. It may interact with medications such as warfarin (Coumadin) and some diabetes drugs. And it's expensive.
No serious side effects have been reported, but some users have experienced stomach upset, heartburn, nausea, dizziness and headaches. Of more concern, its long-term safety is still unknown.
If you have heart disease, high blood pressure, or Parkinson's disease and are considering CoQ10, discuss it with your doctor first. If you have heart failure, there are effective drugs; at best, CoQ10 would be an adjunct therapy.
Source: Originally published in The University of California, Berkeley Wellness Letter (April 2011)