A perfect 10: the rise of ubiquinone.
Q: Tell me a little about the discovery and history of CoQ10.
A: Coenzyme Q10 (CoQ10) was first isolated by Dr Frederick L. Crane in 1957 at the University of Wisconsin. A year later, in 1958, University of Texas professor Dr Karl Folkers determined the precise structure of CoQ10. The first clinical research on CoQ10 began appearing in medical journals in the late 1960s. It is also known as ubiquinone (ubiquitously occurring quinone) because of its widespread presence in living organisms. In healthy individuals, CoQ10 can be biosynthesized to a certain degree. Coenzyme Q10 is liposoluble and has 10 isoprene units. It exists in nature and in the body in two forms: the oxidized form, called ubiquinone, and the reduced form, ubiquinol. CoQ10 is an essential carrier for the electron transfer in the mitochondrial respiratory chain for the synthesis of ATP, and its reduced form (ubiquinol) acts as an important antioxidant in the body. Through these functions, CoQ10 supplementation has beneficial effects in humans for the maintenance of good health. Coenzyme Q10 is present in a variety of foods: higher levels of CoQ10 are found in meat and fish whereas vegetables and dairy products contain relatively low levels.
Q: Why is CoQ10 important for maintaining sufficient energy levels? A: It is well established that CoQ10 is essential for cellular energy conversion and ATP production in all cells of the body. Therefore, it plays a crucial physiological role in maintaining good health. ATP is a high-energy phosphate substance necessary to fuel all cellular functions. The major part of ATP production occurs in the inner membrane of mitochondria, where CoQ10 is located as a vital electron and proton carrier in mitochondrial electron transport. CoQ10 supports ATP synthesis in the mitochondrial inner membrane and stabilizes cell membranes, thus preserving cellular integrity and function. Regarding energy and sporting activity, CoQ10 is reported to function by improving physical work capacity (especially, in aerobic exercise) through the activation of energy supply and favourable effects on lipid metabolism, and also through its antioxidative muscle-protective action.
Q: Could you expand on Q10's antioxidant function?
A: CoQ10, in its reduced form (ubiquinol), acts as an antioxidant. Ubiquinol represents more than 80% of the total CoQ10 pool in human plasma and is an important antioxidant in plasma lipoproteins. Ubiquinol inhibits protein and lipid oxidation in cell membranes, and it prevents the initiation of lipid peroxidation, oxidative injury to DNA and other molecules. CoQ10 acts as an antioxidant through several mechanisms that essentially fall into two categories: direct reaction with free radicals and regeneration of the active form of vitamin E by reducing the alpha-tocopheryl radical. Peroxidation of plasma lipoproteins, namely LDL, is known to play an important role in the formation of foam cells and in the development of the atherosclerotic process. Studies in the last decade have demonstrated that the content of CoQ10 in human LDL affords some protection against the oxidative modifications of LDL themselves, thereby lowering their atherogenic potency. Studies on isolated serum lipoproteins point out that CoQ10 is the most reactive antioxidant in these particles and protects them from oxidative damage.
Anti-ageing: The ageing process is fundamentally influenced by CoQ10. The mitochondrial respiratory chain is a powerful source of reactive oxygen species, which are thought to play a major part in the deterioration of cell structures accompanying ageing. As CoQ10 is an integral part of the respiratory chain and thereby located exactly where the free radicals are generated, its antioxidant properties are very important for the overall antioxidative capacity of the mitochondria.
Q: Why is CoQ10 important for heart health?
A: Coenzyme Q10 helps to maintain a healthy cardiovascular system. There is evidence of CoQ10 deficiency in hypertension, heart failure and in statin-treated hypercholesterolemic individuals.
Blood pressure: Blood pressure is a well-established biomarker for heart health. A meta-analysis of 12 clinical trials of CoQ10 for hypertension has shown that CoQ10 is effective in lowering systolic blood pressure by up to 17 mm Hg and diastolic blood pressure by up to 10 mm Hg without significant adverse events.
Heart function: There is substantial evidence that heart function is improved by the supplementation of CoQ10. A meta-analysis of the use of CoQ10 (60-200 mg/ day) in randomized clinical trials in people with congestive heart failure showed a significant and clinically relevant improvement in various parameters of heart function. A comprehensive review of the use of CoQ10 (50-200 mg/day for 1-12 months) in cardiovascular indications showed that the adjuvant supplementation with CoQ10 in people with chronic heart failure should be recommended.
Statins: Statins (HMG CoA reductase inhibitors, cholesterol lowering drugs) may decrease body CoQ10 levels below the threshold that is required for numerous cellular processes. The depletion of CoQ10 is doserelated and could be particularly important in the elderly, for whom CoQ10 levels are generally low, but also in those with pre-existing heart failure conditions. Statin-induced CoQ10 deficiency is completely preventable with supplemental CoQ10, with no adverse impact on the cholesterol lowering or the anti-inflammatory properties of the statin drugs.
Q: As this issue of NBT also focuses on male health, I understand that Q10 also has a role in sperm cell motility.
A: As demonstrated in the Lewin et al. article (Mol. Aspects Med. 18, S213-219 ), "The Effect of Coenzyme Q10 on Sperm Motility and Function," the majority of coenzyme Q10 in sperm cells is concentrated in the mitochondria, so that the energy for movement and all other energy-dependent processes also depend on the availability of CoQ10. The reduced form of CoQ10, ubiquinol, also acts as an antioxidant, preventing lipid peroxidation in sperm membranes. The administration of CoQ10 may result in improved sperm functions in certain patients.
Q: Are there any safety issues associated with yeast-fermented Q10? A: After more than 30 years of use in humans and many clinical studies with natural yeast-fermented CoQ10, there are no reports of serious adverse effects associated with daily supplements of CoQ10. In a 52-week oral gavage chronic toxicity study in rats, it was concluded that even a high dose of CoQ10 (1200 mg/kg/day for 52 weeks) was well tolerated by male and female rats, and the NOAEL of CoQ10 could be estimated to be 1200 mg/kg/day. This suggests an acceptable daily intake (ADI) of 12 mg/kg/day, calculated from the NOAEL by applying a safety factor of 100; that is, 720 mg/person/day for a 60 kg person. The safety assessment of CoQ10 in healthy adults (n=88) was assessed in double-blind, randomized, placebo-controlled trials at supplementation levels of 300, 600 and 900 mg for 4 weeks. It was found to be well tolerated and safe for healthy subjects at intakes of up to 900 mg/day. On the basis of published data from clinical studies with natural yeast-fermented CoQ10, a risk assessment for CoQ10 was performed according to the safety evaluation method of the Council for Responsible Nutrition (CRN). The results indicated that a NOAEL could not be set, because no adverse effect that is causally related to CoQ10 in humans could be found. Therefore, the observed safety level (OSL) for CoQ10 was identified as 1200 mg/ day. Australian authorities (TGA) have noted a recommended maximum daily dosage of 150 mg. The Japan Health Food and Nutrition Food Association has proposed that the maximum daily intake of CoQ10 should be 300 mg/day and the Belgian authorities have proposed a maximum intake of 200 mg per day as a food supplement.
Q: What is the regulatory status of Q10? A: CoQ10 is a well-established ingredient that is present in a number of food supplements, functional foods and cosmetics all over Europe. It is available in dosages of up to 200 mg, whereas the recommended dosage for food supplements falls between 30 and 100 mg/day.
Q: How is the current economic downturn affecting the Q10 market? A: Because consumers can genuinely feel the benefit of taking higher doses of CoQ10, the market for this ingredient is not actually suffering from the current crisis. A recent US survey, as noted above, showed that 50.9% of respondents take CoQ10 (making it the fourth most widely used supplement after multivitamins, fish oils and calcium). Almost 30% of people under 35 are taking CoQ10, whereas 60.1% of consumers over the age of 65 take it. Elderly consumers favour food (dietary) supplements, with an increase in use that correlates with age. Younger people (under 35) favour nutrition drinks, and 78.9% of heavy supplement users (taking more than 10 supplements per day) take CoQ10.
Q: What do you see in the future for Q10?
A: There is great potential for CoQ10 in Europe! Consumer awareness of the ingredient and its multiple benefits is still under-developed, in comparison with the US, but it is steadily growing, particularly in some areas. Moreover, the active antioxidant form of CoQ10 (ubiquinol) will gradually become more prevalent in Europe and represents the future of CoQ10. An important trial, conducted by Dr Langsjoen, et al. (Biofactors 32, 119-128 ), suggests that high doses of ubiquinol (but not high doses of ubiquinone) is an excellent way to improve the status of severe (NYHA Class IV) chronic heart failure (CHF) patients. Dr Langsjoen also claims that it is likely that ubiquinol would show even more clinical benefits in early stage CHF patients. Ubiquinol is appropriate for direct use by middle--to senior-aged people and those with increased oxidative stress who no longer have the same capacity to convert ubiquinone into ubiquinol.
* www.jhnfa.org (in Japanese)
For more information
Dr Kevin Robinson is the Editorial Director of nutraceutical business & technology (NBT) and can be reached at firstname.lastname@example.org.
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|Title Annotation:||Coenzyme Q10|
|Publication:||Nutraceutical Business & Technology|
|Date:||Mar 1, 2009|
|Next Article:||Antioxidant claims: immune to the EFSA cull?|