Given the impressive claims for the nutrient, it's not surprising that it's so popular. It's long been famous for its heart-health benefits, but CoQ10 is also purported to boost energy, reduce migraines, aid weight loss, heal periodontal (gum) disease, counteract infertility and slow the development of Parkinson's.
So, should CoQ10 be a staple supplement for all of us?
What is CoQ10?
CoQ10, also called 'ubiquinone', is a vitamin-like compound found in practically every cell of the human body, but especially in the heart. Since its discovery and isolation over 50 years ago, hundreds of studies have been carried out on it, and it's now clear that this nutrient is absolutely vital to health. Not only does it play a crucial role in the production of adenosine triphosphate (ATP), the body's major form of stored energy,
but it's also a powerful antioxidant-with a free-radical-fighting ability 50 times greater than that of vitamin E.
Research shows that the tissues and blood of an adult human contain a total of around 2000 mg of CoQ10, while 500 mg/day is required to maintain this body pool. The average diet provides barely 5 mg/day, so the rest has to be synthesized internally. However, our ability to synthesize CoQ10 appears to decline with age and when we are ill or stressed. Indeed, low CoQ10 levels have been found in a wide range of medical conditions, including heart disease, hypertension (high blood pressure), gum disease and acquired immunodeficiency syndrome (AIDS) (Altern Med Rev, 1996; 1: 11-7). This may explain why supplementing with CoQ10-shown to raise tissue levels of the nutrient-appears to be beneficial for a wide diversity of health problems.
What does it do?
Much of the research into CoQ10 supplementation has been for heart-related problems, so there's now an impressive body of research showing that the nutrient is invaluable for patients with cardiomyopathy (heart muscle dysfunction), congestive heart failure, angina and hypertension, and for those undergoing heart surgery (Altern Med Rev, 1996; 1: 168-75). But CoQ10's benefits go far beyond heart health, as the latest findings suggest.
Migraines. A recent study of more than 1500 young migraine sufferers (aged 3-22 years) found that one-third had abnormally low CoQ10 levels. These patients were asked to take liquid gel capsules of CoQ10 at a dose of 1-3 mg/kg/day to see if their headaches improved. After three months, as the patients' CoQ10 levels increased, their head-ache frequency decreased (Headache, 2007; 47: 73-80).
In another, randomized control-led trial, CoQ10 at 100 mg three times a day was well tolerated and more effective than a placebo for reducing the frequency of attacks, and the number of days with head-ache and/or nausea (Neurology, 2005; 64: 713-5).
Male infertility. CoQ10 may play an important role in sperm quality, with low levels having an adverse effect on both sperm counts and motility (movement), which can have a negative impact on fertility (J Endocrinol Invest, 2009; 32: 626-32). Recently, scientists have begun to investigate whether oral CoQ10 supplements improve sperm quality in infertile men. When 60 men with infertility due to asthenozoospermia-poor sperm motility-were given 200 mg/day of CoQ10 or a placebo for six months, levels of CoQ10 were significantly increased in the patients' sperm, while sperm motility was improved. What's more, of nine pregnancies that occurred during the study, six were by men treated with CoQ10 (Fertil Steril, 2009; 91: 1785-92).
Parkinson's disease. CoQ10 may also be a ray of hope in Parkinson's and other neurodegenerative dis-orders. When 80 patients with early Parkinson's were randomly assigned to receive CoQ10 at a dose of 300, 600 or 1200 mg/day, or a placebo, after 16 months, those taking the placebo showed a slight progression of their disease, whereas all of those taking CoQ10 saw less disease progression. This was most striking in those taking the highest dosage, who experienced 44-per-cent less disability due to their symptoms (Arch Neurol, 2002; 59: 1541-50).
Preliminary evidence also shows that CoQ10 supplements might be able to slow the decline of patients with Huntington's disease and Friedreich's ataxia (Neuropsychiatr Dis Treat, 2009; 5: 597-610).
Gum disease. CoQ10 may be helpful for periodontal disease, which affects around 60 per cent of young adults and 90 per cent of those over age 65. Low CoQ10 levels have been reported in as much as 96 per cent of patients with the problem, so supplementation may be beneficial in most cases. When 18 patients with gum disease took either 50 mg/day of CoQ10 or a placebo in a three-week double-blind trial, all eight of those taking CoQ10 improved compared with only three of the 10 taking the placebo. The dentists, who did not know they were in a study, consistently noted that the rate of healing in patients treated with CoQ10 was "very impressive" (Altern Med Rev, 1996; 1: 11-7).
o Obesity. The tend-ency towards being overweight is, in some people, related to energy production. As CoQ10 is an essential cofactor in energy production, it's been suggested that CoQ10 deficiency might be involved in some cases of obesity. Indeed, a study of 27 obese patients found that half had low CoQ10 levels. When five of these deficient patients took 100 mg/day of CoQ10 with a daily diet of 650 calories, all lost more than twice as much weight as those who were not low in CoQ10 and on the same diet-supplement protocol (Altern Med Rev, 1996; 1: 11-7).
However, another study found no differences between CoQ10 levels in obese and normal-weight children (Clin Chim Acta, 2004; 349: 121-7). Evidently, more research is needed to evaluate the precise role of CoQ10 in obesity.
Chronic fatigue syndrome (CFS). Belgian researchers found that almost half of their CFS patients were CoQ10-deficient, and that there was a significant relationship between CoQ10 levels and patients' symptoms. Those with the lowest levels reported more fatigue, and concentration and memory distur-bances (Neuro Endocrinol Lett, 2009; 30: 470-6). However, it's not clear that CoQ10 supplements would work in CFS patients, although one study found that 100 mg/day for three months improved exercise tolerance in 20 women with CFS compared with 20 non-CFS controls. Moreover, 90 per cent saw a reduction or even disappearance of clinical symptoms, while 85 per cent showed less post-exercise fatigue (Altern Med Rev, 2000; 5: 93-108).
Cancer. So far, evidence suggests that CoQ10 might help people with cancer. In one study, 32 women classified as having a 'high risk' of breast cancer were given 90 mg/day of CoQ10, to be taken with other antioxidants (vitamins C and E, beta-carotene and selenium) and essential fatty acids. During the 18-month treatment period, the main observations were: (1) no patients died (the expected number was four); (2) no patients showed signs of further metastases (spread); (3) quality of life was improved (no weight loss, less use of painkillers); and (4) six patients saw a partial remission of their cancer (Mol Aspects Med, 1994; 15 Suppl: s231-40).
Also, in the case of a 49-year-old woman with breast cancer that had spread to around the lungs, after six months of high-dose CoQ10 therapy (390 mg/day), there were no signs of tumour in the pleural cavity, and her condition was reported to be "excellent" (Biochem Biophys Res Commun, 1995; 212: 172-7).
More recently, a pilot study looked at the survival of 41 patients with end-stage cancer who were given supplements of CoQ10 and other antioxidants. Their average survival time was 40-per-cent longer than the average predicted survival time. In total, 76 per cent of the patients survived for longer than predicted (J Int Med Res, 2009; 37: 1961-71).
However, until the next stage of controlled trials are done, we can't really tell whether or not CoQ10 is truly an effective anticancer agent-although the results so far are promising.
CoQ10 for all?
Clearly, CoQ10 appears to be useful in a wide variety of common conditions, and the list is by no means complete. The people most likely to benefit are those who are deficient in the nutrient. As CoQ10 plays a vital role in the body, not getting enough is likely to have detrimental effects.
Nevertheless, it's unclear whether CoQ10 supplements are of any benefit in healthy people. Although one recent trial found that CoQ10 at 100 mg/day improved exercise performance in healthy, sedentary men (J Strength Cond Res, 2010; 24: 97-102), another found that the nutrient (150 mg/day, with or without 1000 IU/day of vitamin E) had no performance-enhancing effects in healthy, physically active men (J Sports Med Phys Fitness, 2005; 45: 337-46).
Also, in mouse studies, while some of the findings suggest that CoQ10 may play a significant anti-ageing function-apparently prolonging life by reducing oxidative stress-others have failed to show any such effects (Free Radic Biol Med, 2006; 40: 480-7). Indeed, one study even found that the long-term intake of high-dose CoQ10 made the age-related cognitive and sensory impairment in these animals worse (J Nutr, 2009; 139: 1926-32). Of course, these results may not apply to humans.
There's no doubt that more studies are needed to ascertain the role of CoQ10 supplementation. So far, however, it appears to be a potentially useful supplement for many of us-and one that actually appears to live up to (most of) its claims.
Dosage and safety
In adults, the dosage of coenzyme Q10 is usually 30-90 mg/day, although people with specific health conditions should perhaps supplement with larger doses (but only with the guidance of a qualified practitioner). Most of the research on heart conditions has used 90-150 mg/day of CoQ10.
Studies also suggest that solubilized formulations of CoQ10 (using either ubiquinone, the oxidized form, or ubiquinol, the reduced form) are the most bioavailable-in other words, they are readily taken up by the body to be put to use (Mitochondrion, 2007; 7 Suppl: S78-88).
CoQ10 causes no serious adverse effects in humans (Expert Opin Investig Drugs, 2010; 19: 535-54), although minor side-effects have included nausea, heartburn and stomach upset.
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