Coenzymes are organic molecules that support the ability of enzymes to use vitamins and minerals. Unlike regular enzymes, coenzymes are not proteins. Many types of coenzymes incorporate vitamins into their chemistry. Some, like Q10, may help reduce side effects of some cholesterol-lowering drugs. While practical, the benefits of coenzymes as health supplements are not well-established. There are 18 known coenzymes, broadly classified in two groups.
Most coenzymes originate as vitamins that the body absorbs through food before converting them to do their jobs. Vitamins enable the body’s cells to perform chemical reactions; process nutrients, carbohydrates and fats; and regulate the nervous system.
Coenzymes derived from vitamins include ascorbic acid (from vitamin C), coenzyme A (from pantothenic acid or B5), coenzyme F420 (from riboflavin), menaquinone (from vitamin K), NAD+ and NADP+ (from niacin) and tetrahydrofolic acid (from folic acid or B9).
Coenzymes not derived from vitamins can still transfer different chemicals between enzymes. These include adenosine triphosphate (which transfer phosphates); S-Adenosyl methionine, Tetrahydromethanopterin and and coenzyme M (which transfer methyls); 3'-Phosphoadenosine-5'-phosphosulfate (which transfer sulphates); glutathione, coenzyme Q and coenzyme B (which transfer electrons); tetrahydrobiopterin (which transfer oxygen and electrons); cytidine triphosphate (which transfer lipid head groups and diacylglycerols); nucleotide sugars (which transfer monosaccharides); Methanofuran (which transfer formyls).
Methanogens distribute Coenzyme M, coenzyme B, methanofuran and tetrahydromethanopterin through the body; bacteria, archaea and eukaryotes distribute the other coenzymes.
Organizations such as the Mayo Clinic and the National Cancer Institute question the proven benefits of coenzyme Q10 supplements. Statins, which treat high cholesterol, sometimes have detrimental side effects including muscle pain, liver damage, digestive problems, rashes and memory loss. Q10 has been used to alleviate these problems but the effectiveness is controversial.
As a dietary supplement, Q10 is not regulated by the Food and Drug Administration, and no large studies have been performed to check how well it helps statin users, if at all. While no liver problems have been reported from Q10, an Italian study by E. Baggio, R. Gandini, and A.C. Plancher (et al) reported rashes, nausea and upper abdominal pain from a small number of patients.