Where it comes from: Coenzyme Q10 (CoQ10) is a naturally-occurring compound found in every cell of the body. It's used to produce energy for cell growth and maintenance, and functions as an antioxidant. CoQ10 in pill form has been approved for heart failure treatment in Japan since 1974. In the United States, it's approved as a dietary supplement. The pills are also sometimes called Q10, vitamin Q10, ubiquinone or ubidecarenone.
What it'll do for you: Coenzyme Q10 is a disease-fighting antioxidant and has been used in the treatment of neurological diseases and may (studies are still preliminary) be beneficial in cancer, heart disease, high blood pressure and migraine headache treatment.
In 1961, scientists noticed that people with cancer (such as lymphoma, lung cancer, prostate cancer and colon cancer) had little CoQ10 in their blood. The CoQ10 may help the immune system and may keep anti-tumor drugs from hurting the heart. While the National Institutes of Health and the National Cancer Institute rate the strength of evidence for CoQ10 and cancer benefits as weak, researchers continue to look for affirming indications. In three studies of women with breast cancer, women across the board showed improvement when given supplements. More research is needed in terms of all cancers—particularly ones that inflict men.
- Cardiovascular conditions
After more than 20 years of research, experts still disagree about the benefits of CoQ10 for people with heart failure. Studies show that it has little or no effect in treating heart failure or angina and it's not recommended for people with these health problems. However, studies do show that CoQ10 can help lower blood pressure. A 2001 study examined 83 people with high blood pressure. They took either 60 mg of CoQ10 or a placebo pill and those who took the supplement saw an 18-point (18 mm Hg) reduction in systolic blood pressure (the higher number). Those on the placebo only saw a two-point reduction. Low blood levels of CoQ10 have been found in people with hypertension, although it is unclear if the two are inversely related.
- Migraine prevention
In 2004, Swiss researchers reported that Coenzyme Q10 proved to have a significant effect in reducing migraine occurrences. They theorized that migraines may be caused by a decrease in mitochondrial energy, and that CoQ10 gives energy to boost the brain. In their three-month study of 42 patients (some taking CoQ10 and others taking a placebo), about 48 percent of those taking CoQ10 had a 50 percent response rate. The number of migraine attacks per month was reduced in the treatment group from 4.4 to 3.2.
Other preliminary studies have found the CoQ10 could be useful in treating muscular dystrophy, periodontal disease and speeding recovery from exercise.
Suggested intake: Small amounts of CoQ10 are already naturally present in a variety of foods, but levels are particularly high in organ meats (such as heart, liver and kidney), as well as beef, soy oil, sardines, mackerel and peanuts.
There have been no reports of negative side effects of coenzyme Q10 supplementation at doses as high as 1200 mg per day (up to 16 months) and 600 mg per day (up to 30 months). As such, 1,200 mg per day has been recently identified as the observed safe level (OSL) for coenzyme Q10. If you do add a supplement to your diet, says Marissa Lippert, RD and author of The Cheater's Diet, reach for a reputable brand (such as Nature's Bounty or Centrum) and, of course, talk to your doctor before taking anything.
Associated risks/scrutiny: Not many serious risks have been reported. Mild side effects include rashes, nausea, upper abdominal pain, dizziness, loss of appetite sensitivity to light, irritability, headache, heartburn and fatigue.
"Individuals with sensitive blood sugar levels and those with low blood pressure, be advised that CoQ10 can lower both of these levels," Lippert warns. In those cases, she says supplementation should be carefully monitored or foregone. Supplements may interact with certain medications (particularly blood thinners) and Statin drugs may inhibit synthesis of CoQ10.
Taking 100 mg a day or more of CoQ10 has caused mild insomnia in some people. And research has detected elevated levels of liver enzymes in people taking doses of 300 mg per day for long periods of time.
While CoQ10 is sometimes used to help speed recovery from exercise, there is little evidence that it improves athletic performance in healthy individuals. At least seven tests have examined the effects of coenzyme Q10 supplements (in doses of 100-150 mg per day for three to eight weeks) on physical performance in trained and untrained men. Most found no significant differences between groups taking the supplements and those taking placebos when it came to aerobic exercise performance.