Coenzyme Q10

defining coenzyme Q10
Coenzyme Q10 (CoQ10) exists naturally in mitochondria—the source of energy in cells—and carries electrons involved in energy metabolism. It is also an antioxidant, meaning it counteracts the negative effects of oxygen and free radicals in tissue.

clinical applications
As one of its antioxidant functions, CoQ10 inhibits oxidation of low-density lipoprotein (LDL) cholesterol, which is believed to play a role in the development of atherosclerosis (hardening of the arteries). CoQ10 also helps reduce high blood pressure and increase mental clarity, and there is some evidence that it improves the symptoms and complications of diabetes.

(Heart health) Recent studies have shown CoQ10 reduces the risk of atherosclerosis. In one study, patients who had recently suffered heart attacks were divided into two groups. One group was treated with 120 mg per day of CoQ10; the control group was given vitamin B. After one year, nonfatal heart attacks and cardiac deaths were significantly lower in the group taking CoQ10 compared to the control group.

(blood pressure control) A recent placebo-controlled study looked at CoQ10’s ability to lower blood pressure. Systolic blood pressure in the participants receiving CoQ10 was reduced significantly, suggesting CoQ10 may be a treatment option for people with high blood pressure. Other studies, however, indicate that people with high blood pressure should not rely on CoQ10 as treatment until more clinical trials demonstrate consistent beneficial effects.

(brain function) CoQ10 may help patients with brain disorders. Oxidative stress, deficiency in the mitochondria (the parts of cells responsible for producing energy), and visual problems—all features of Parkinson’s disease—are associated with CoQ10 deficiency. A study of people with Parkinson’s disease found a daily 360-mg dose of CoQ10 significantly reduced their symptoms. Another study showed CoQ10 slows the loss of dopaminergic neurons, which is a key indicator of Parkinson’s disease. CoQ10 has been shown to slow the functional mental decline seen with Parkinson’s disease and Huntington’s disease—both disorders in which mitochondrial function is impaired.

(diabetes symptoms and complications) A few studies have shown positive effects of CoQ10 on symptoms and complications of diabetes. A recent study shows that CoQ10 may improve blood pressure and long-term glycemic control in patients with type-2 diabetes, but the evidence is not overwhelming. Some studies say that CoQ10 is not effective as a treatment for diabetes symptoms; others show effectiveness in treating some, but not all, symptoms.

side effects & interactions
A few reports suggest CoQ10 decreases the effectiveness of warfarin (a blood thinner); others counter this claim. In some cases, doses of over 200 mg caused diarrhea and/or nausea. Pregnant women and nursing mothers should not take CoQ10 due to the lack of long-term safety studies.

sources & dosages
CoQ10 is found primarily in fish and meats, but only in small amounts. It is derived in supplemental form from tobacco leaf extracts, fermented sugar cane, and beets. Doses range from 5 to 300 mg per day.

final thoughts
Studies about the beneficial effects of CoQ10 are ongoing. To date, it has demonstrated particular usefulness in promoting heart health, managing blood pressure, and improving symptoms of Parkinson’s and other neurodegenerative diseases.