What is CoQ10?
Coenzyme Q10 Biosynthesis: How is it Made by the Body?
Every cell in the body is capable of coenzyme Q10 biosynthesis. Each cell makes a different amount, depending upon its tissue type and energy requirements. Cells in organs that are very active and have high energy requirements such as the heart, brain and liver make the most coenzyme Q10 and contain the highest amounts. Unfortunately, the body’s ability to make coenzyme Q10 declines with age. Peak production occurs at about age 21 and gradually declines thereafter. 1 It has been shown that coenzyme Q10 levels fall with age in both heart and brain tissue as illustrated in the figure below.
In addition, body stores of coenzyme Q10 may be reduced by a variety of external factors such as certain medications, hormone levels, alcohol consumption, nutritional depletion, strenuous exercise, elevated cholesterol and triglycerides, and stressors such as illness and extreme cold. Due to the reduced production of coenzyme Q10 with age, in combination with factors which reduce body stores, our bodies may be unable to make enough coenzyme Q10 to meet our daily needs. In this case, we must consume sufficient amounts of coenzyme Q10 in the diet if we are to avoid coenzyme Q10 deficiency.
Dietary Coenzyme Q10
Dietary coenzyme Q10 is found in many foods including beef, beans, eggs, oils, fish, nuts and grains. It is found in highest amounts in the meat of organs which require large supplies of energy to function such as heart, liver, kidney and brain. Dietary coenzyme Q10 can be divided into rich sources, such as meat, poultry, fish, vegetable oils, and nuts; and less rich sources such as fruits, vegetables, eggs, dairy, and cereals.
Few people eat enough of these foods to replenish their daily losses. For example, in order to consume 50 mg of coenzyme Q10, one would have to eat 3.3 lbs. of beef or 4.2 lbs. of peanuts! A Danish study of coenzyme Q10 intake demonstrated that the average daily intake was only 3-5 mg, coming mostly from meat (64%) and poultry. 2 Vegetarians may be at particular risk because so many of the coenzyme Q10 rich food sources are animal based. In addition, only about 10% of ingested coenzyme Q10 is actually absorbed into the body due to its poor bioavailability. Also, when these foods are cooked above 122 degrees F, the coenzyme Q10 content can be destroyed. Frying meat causes a 14-32 % loss of coenzyme Q10 . Thus, for many people, the way to avoid coenzyme Q10 deficiency is to ingest it as a dietary supplement.
Originally, coenzyme Q10 was extracted from beef hearts for supplemental use but the high expense of this process prevented full scale commercialization. The Japanese have provided mass-production of coenzyme Q10 via a fermentation process developed in the 1970’s and new, synthetic methods have recently been developed. Dietary supplements are available in the form of pills, liquids or wafers. They can be taken for supplemental use (to make up for a poor diet) or therapeutic use. The U.S. Dietary Reference Intake (DRI), formally the U.S. Recommended Daily Allowance (RDA) for coenzyme Q10 has not been established, however, various organizations have made recommendations for daily doses that range widely from 30 to 350 mg for healthy individuals. The dose of coenzyme Q10 that has been used therapeutically ranges from 100 mg to as high as 3,000 mg, way beyond that which could be consumed in the diet.
How Coenzyme Q10 Works in the Body
Coenzyme Q10 has two primary functions in the body. The first is to produce energy by contributing to the manufacture of a small molecule called adenosine triphosphate (ATP). ATP is the energy “currency” of life and is required by all cells to fuel bodily functions. The second function, like that of vitamins C and E, is that of an antioxidant. Antioxidants defend the body from cellular damage caused by oxidative stress. The damage is caused by free radicals which are formed normally during metabolism, as part of natural immunity, or upon exposure to environmental factors such as pollution, ultraviolet (UV) radiation, cigarette smoke and herbicides.
Because it is necessary for all bodily functions, it is not surprising that a relative reduction in coenzyme Q10 has been associated with a variety of disease states including, cardiovascular diseases such as congestive heart failure, stroke and atherosclerosis, neurodegenerative diseases such as Alzheimer’s, Multiple Sclerosis and Parkinson’s, AIDS, cancer, periodontal disease and skin damage from the sun and pollution exposure. Some clinical studies have demonstrated beneficial effects of treatment of these diseases with coenzyme Q10. Certain drugs can affect levels of coenzyme Q10 in the body. The statin drugs are probably best known for this. Statins reduce cholesterol, which the body makes using the same synthetic pathway that produces coenzyme Q10 . The statins work by blocking this pathway resulting in reduced production of both cholesterol and coenzyme Q10. It is believed that the reduction in coenzyme Q10 associated with statins contributes to some of their side effects such as fatigue and muscle weakness. Beta-blockers and antidepressants have also been implicated in adversely affecting coenzyme Q10 levels.
Safety of Coenzyme Q10
Coenzyme Q10 is generally well tolerated and no serious side effects have been associated with its use, even with doses up to 3000 mg/day in patients with Parkinson’s disease. 3 With oral use, mild gastrointestinal symptoms such as diarrhea, indigestion, and nausea have been reported in less than 1% of patients in clinical trials. The safety of coenzyme Q10 in pregnant or lactating women has not been studied. 4
Coenzyme Q10 has been shown to be safe when topically applied to the skin. It does not cause skin irritation, even in people who have sensitive skin and suffer from stinging when certain cosmetics are applied. 5
More information can be found at The Linus Pauling Institute Micronutrient Information Center
References:
- Kalen A, Appelkvist E-L, Dallner G: Age related changes in the lipid composition of rat and human tissue. Lipids 1989;24:579-584.
- Overvad K, Diamant B, Holm L, Holmer G, Mortensen SA, Stender S. Coenzyme Q10 in health and disease. Eur J Clin Nutr. 1999;53(10):764-770.
- Weber C. Dietaty intake and absorption of coenzyme Q10. In: Kagan VE, Quinn PJ, eds. Coenzyme Q10 Molecular Mechanisms in Health and Disease. Boca Raton: CRC Press; 2001:209-215.
- Shults CW, Flint Beal M, Song D, Fontaine D. Pilot trial of high dosages of coenzyme Q10 in patients with Parkinson’s disease. Exp Neurol. 2004 Aug;188(2):491-4.
- The Medical Letter 2006;48(1229):19.
- Hoppe U, Bergemann J, Diembeck W, Ennen J, Gohla S, Harris I, Jacob J, Kielholz J, Mei W, Pollet D, Schachtschabel D, Sauermann G, Schreiner V, Stäb Steckel F. CoQ10, a cutaneous antioxidant and energizer. Biofactors 1999;9:371-378.