Coenzyme Q10 is a fat-soluble nutrient also known as CoQ10, or ubiquinone. It is primarily found in the mitochondria, which are small bodies within cells that produce energy for the body. Apart from the important process that provides energy, CoQ10 also stabilizes cell membranes and acts as an antioxidant (a substance that reduces damage that results from free radical oxygen).

Purpose

Some people believe and anecdotal data suggest that oxygen-derived radicals are involved in the origins and development of cancer. Oxygen-derived radicals may cause damage to membranes, mitochondria, and large molecules, including proteins, lipids, and DNA. Accumulation of DNA damage may contribute to the development of cancer. There may be a relationship between oxidative stress and breast cancer development. People who subscribe to the belief that antioxidants are health-promoting may consume coenzyme Q10 (CoQ10) as one way of maintaining their health. However, as of 2005, this belief has not been conclusively proven by medical institutions.

Increased antioxidant enzyme activities may affect susceptibility of cells to cancer-causing agents and the response of tumor cells to chemotherapy. Administration of coenzyme Q10 by nutrition may induce the protective effect of coenzyme Q10 on breast tissue.

Furthermore, coenzyme Q10 is reputed to reduce the toxicity of some types of chemotherapy. Doxorubicin, a chemotherapeutic agent, is known to sometimes damage the heart. But use with coenzyme Q10 may reduce this toxic effect. People who are considering taking coenzyme Q10 should discuss its possible benefits of with a nutritionally oriented healthcare provider.

Description

Coenzyme Q10 appears to help ignite the cellular power stations that are necessary to maintain healthy cells, enhancing energy at the cellular level. The powerful antioxidant is highly concentrated in heart muscle cells. Coenzyme Q10 is believed by some to be an immune system booster and antioxidant that may help people avoid getting cancer, and it may be useful in treating it. Apart from its important function of providing energy, CoQ10 also stabilizes cell membranes, and as an antioxidant, it destroys free radicals in the body. These unstable molecules can cause damage to normal cells.

CoQ10 occurs naturally in many foods, which provide approximately half of the body's requirement. Cold-water fish such as mackerel, salmon, sardines, and tuna are particularly high in CoQ10. Meats and vegetable oils are also good sources. The human liver manufactures adequate amounts to fulfill the need not met in the diet. Some whole food nutritionists may believe that people who are deficient in B vitamins, selenium, vitamin C, or vitamin E may not be able to make as much coenzyme Q10 as they need since all these nutrients are required in order to produce it. The belief is that liver production and consumption of foods rich in CoQ10 may not provide the amounts needed to treat certain cancers, and for that reason, some people consume the enzyme in supplement form. It can be found formulated as capsules, gel caps, liquids, and tablets. The latter may be the best choice as it generally includes a source of fat that improves absorption. Vitamin E is a helpful stabilizing additive as well.

Coenzyme Q10 was first identified in 1957. Its chemical structure was determined in 1958. Interest in coenzyme Q10 as a potential treatment for cancer began in 1961, when a deficiency of the enzyme was noted in the blood of cancer patients. Low blood levels of coenzyme Q10 have been found in some patients with myeloma (a malignant tumor that develops in the blood-cell-producing cells of the bone marrow), lymphoma (cancer of the lymph nodes), and cancers of the breast, lung, prostate, pancreas, colon, kidney, and head and neck, according to the National Cancer Institute (NCI).

Recommended Dosage

Coenzyme Q10 is usually taken by mouth as a tablet or capsule. It may also be given by injection into a vein. CoQ10 is available in oil-based capsules, powder-filled capsules, tablets, and liquid soft gels. The soft gels are believed to give higher absorption. Therapeutic dosages of CoQ10 for cancer range from 200 to 600 mg per day. As a general nutritional supplement, daily doses of CoQ10 range from 5 to 300 mg. Those who use CoQ10 for periodontal (the tissue around teeth) health may take 100–150 mg daily. The same dose range applies to those who take statin (cholesterol-lowering) drugs for treatment of high cholesterol. CoQ10 is best taken with food. About three weeks of daily dosing are necessary to reach maximum blood concentrations of CoQ10. It comes in the various dosages.

Precautions

Coenzyme Q10 should not be taken by persons who are allergic to it. Symptoms of an allergic reaction include breathing problems or tightness in the throat or chest, chest pain, and skin hives, rash, or itchy or swollen skin. No other known precautions are indicated for normal dosage.

Side Effects

No serious adverse side effects have been reported. Some patients using coenzyme Q10 have experienced mild insomnia, elevated levels of liver enzymes, rashes, nausea, and upper abdominal pain. Other reported side effects have include dizziness, visual sensitivity to light, irritability, headache, heartburn, and fatigue.

Interactions

Patients should talk with their healthcare provider about possible interactions between CoQ10 and prescription drugs they may be taking. Certain drugs, such as those that are used to lower cholesterol or blood sugar levels, may reduce the effects of CoQ10. CoQ10 may also alter the body's response to warfarin, a drug that prevents the blood from clotting, and insulin, used to treat diabetes. The cholesterol-lowering drugs known as statins, such as lovastatin (Mevacor), simvastatin (Zocor), and pravastatin (Pravacol) may decrease CoQ10 levels in humans. It is likely that all statins have this effect. Also, CoQ10 may improve glycemic control in some type II diabetics. If this were to occur, antidiabetic medications might need appropriate adjusting. Some beta-blockers, in particular propanolol, may inhibit some CoQ10-dependent enzymes. Piperine, found in black pepper, may increase levels of CoQ10 in the blood.

—Ken R. Wells

Coenzyme Q10 - The Wonder Nutrient

by Hans R. Larsen, MSc ChE

What does congestive heart failure, gum disease and obesity have in common? Very often, a deficiency of coenzyme Q10 (CoQ10). A lack of CoQ10 has also been implicated in arrhythmias, strokes, hypertension, heart attacks, atherosclerosis, muscular dystrophy and AIDS and many of these diseases can be prevented and treated successfully with CoQ10. Since its discovery and isolation 40 years ago hundreds of clinical research studies have been done on CoQ10 and it is now abundantly clear that this nutrient is absolutely vital to health(1-5).

Coenzyme Q10 (ubiquinone/ubiquinol) is a fat-soluble quinone with a structure similar to that of vitamin K. It is a powerful antioxidant both on its own and in combination with vitamin E and is vital in powering the body's energy production (ATP) cycle. CoQ10 is found throughout the body in cell membranes, especially in the mitochondrial membranes and is particularly abundant in the heart, lungs, liver, kidneys, spleen, pancreas and adrenal glands. The total body content of CoQ10 is only about 500-1500 mg and decreases with age(5).

Essential to the heart

Coenzyme Q10 has received particular attention in the prevention and treatment of various forms of cardiovascular disease. It is highly effective in preventing the oxidation of low-density lipoprotein cholesterol (LDL) that leads to atherosclerosis(2,6-8). Several studies have shown that patients with congestive heart failure and other cardiovascular diseases have significantly lower levels of CoQ10 in their heart tissue than do healthy people and supplementation with as little as 100 mg/day has been shown to markedly improve their condition. CoQ10 is now approved in Japan for the treatment of congestive heart failure(2-5,9,10).

Heart attacks and strokes produce a burst of free radicals (ischemia-reperfusion) that can result in extensive tissue damage. Patients with high CoQ10 levels suffer less damage from these events and Japanese researchers have found that CoQ10 supplementation prior to and immediately following open-heart surgery is highly beneficial in preventing reperfusion injury - a common complication in heart surgery(2,4,5,11,12). Supplementation with CoQ10 has also been found beneficial in patients with chronic stable angina, mitral valve prolapse and irregular heart beat (arrhythmias)(2-5,13-15).

Coenzyme Q10 has also proven useful in the treatment of various cardiomyopathies (diseases of the heart muscle that reduces its pumping capacity). Studies have shown that supplementation with as little as 100 mg/day for 12 months results in better pumping capacity (increased ejection fraction), increased muscle strength and improved breathing(2-4,16).

Several studies indicate that CoQ10 may be beneficial in the treatment of hypertension (high blood pressure). A study of 109 patients with long-standing, essential hypertension, who were on antihypertensive drugs, concluded that supplementation with an average of 225 mg/day of CoQ10 improved functional status, allowed about half the patients to discontinue most of their blood pressure medications and resulted in an average decrease of systolic blood pressure from 159 to 147 mm Hg and a diastolic pressure decrease from 94 to 85 mm Hg. Smaller, more recent Japanese studies have confirmed these findings(2-5,17-19).

Studies at the University of Ancona in Italy have provided evidence that CoQ10 supplementation reduces blood levels of epinephrine (adrenalin) and other catecholamines; this is believed to be partly responsible for the drop in blood pressure and may also explain why CoQ10 is effective in reducing the incidence of certain types of arrhythmias(2,20).

Boosts energy and brain power

Coenzyme Q10 is a great boost to heart health, but it has many other beneficial effects. Strenuous physical exercise reduces blood levels of CoQ10 and supplementation with 60 mg/day has been found to improve athletic performance(2,3,21). Administration of CoQ10 alone or in combination with vitamin B6 (pyridoxine) boosts the immune system and may be useful in the treatment of AIDS and other infectious diseases(3,22,23). An adequate level of CoQ10 in the body is essential to proper muscle functioning and several studies have indeed shown that supplementation with 100-150 mg/day of CoQ10 markedly improves the condition of people suffering from muscular dystrophy(2-5,25-28).

Many overweight people have very low levels of CoQ10 and supplementation may enable them to lose weight due to the effect of CoQ10 in speeding up the metabolism of fats(3,4,29).

Some very recent, highly intriguing research carried out at the Institute of Neurosciences in Argentina has shown that brain activity and alertness is enhanced in hypertensive patients within one hour of oral administration of 100 mg of CoQ10(30).

Keeps your gums healthy and fights cancer

CoQ10 has been used with success in combating periodontal diseases, especially gingivitis (gum disease). Tissue affected by gingivitis is deficient in CoQ10 and experiments have shown that supplementation with as little as 50 mg/day can decrease inflammation. More recent research has shown that topical application of CoQ10 dissolved in soy oil (85 mg/ml) to affected areas (periodontal pockets) reduces bleeding and the depth of the pockets(2-5,31-34).

Research carried out in Denmark has provided some tantalizing evidence that CoQ10 may also be effective in the fight against certain cancers. A trial involving the treatment of 32 breast cancer patients with mega doses of vitamins, minerals, essential fatty acids and coenzyme Q10 (90 mg/day) in addition to conventional therapy showed a highly beneficial effect of the supplementation. Two of the patients in the trial whose tumours had not regressed had their CoQ10 dosages increased to 390 mg/day and 300 mg/day respectively with the result that their tumours disappeared completely within three months(3,35). CoQ10 supplementation is also very important for cancer patients undergoing chemotherapy with heart toxic drugs such as adriamycin and athralines. Recent research has also shown that certain cholesterol-lowering drugs (lovastatin, etc.) block the natural synthesis of CoQ10 so supplementation with 100 mg/day is recommended for patients taking these drugs(2,3,36).

So how much do you need?

The body can synthesize coenzyme Q10 and it is also found in several dietary sources, notably organ meats. The level of CoQ10 in human organs peaks around the age of 20 years and then declines fairly rapidly. The decrease in CoQ10 concentration in the heart is particularly significant with a 77-year-old person having 57 per cent less CoQ10 in the heart muscle than a 20-year- old(30). Some experts involved in CoQ10 research believe that many people, especially older people and people engaging in vigorous exercise may be deficient in CoQ10 and may benefit from supplementation. The recommended daily dosage for health maintenance is 30 mg; however, considerably higher amounts are required in the treatment of the various diseases for which supplementation has been found beneficial(2,3,37,38). CoQ10 should be taken with a meal containing some fat or even better, in combination with soy or vegetable oil which enhances its absorption quite substantially(3). The body readily absorbs CoQ10 supplements and no toxic effects have been reported for daily dosages as high as 300 mg. The safety of CoQ10, however, has not been established in pregnancy and lactation, so caution is advised here until more data becomes available(3,5).

REFERENCES

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