There is no US Dietary reference intake, because the body can synthesize Coenzyme Q10; however, deficiency clearly occurs, and can be seen in heart failure, cardiomyopathies, gingivitis, hypertension, Muscular Dystrophy, AIDS, and kidney problems. Low levels also appear more common in older patients.

Useful in Treatment of:
Congestive Heart Failure. People with CHF are deficient in CoQ10.² In several studies, when people with CHF were given CoQ 10 supplements at a dose of 2mg per kg of bodyweight, there was an improvement in symptoms and a decrease in hospitalizations.^3,4,5

Cardiomyopathy. This condition is a weakening of the heart muscle that can lead to heart failure (CHF). Several studies have shown improvement in symptoms in people who took CoQ10 supplements.

Angina. Patients taking 150 mg per day of coenzyme Q10 report a greater ability to exercise without problems.⁹ Other studies have confirmed these findings.¹⁰

Alzheimer’s Disease. Because coenzyme Q10’s has an impact upon the function of mitochondria, one group of researchers has given coenzyme Q10 (along with iron and vitamin B6) to several patients with Alzheimer’s disease and reported that the progression of the disease appeared to have been prevented for one and one-half to two years.¹¹

hypertension. Coenzyme Q10 appears to affect blood pressure by reducing resistance to blood flow.¹² Several studies have reported that supplementation with coenzyme Q10 can reduce blood pressure in people with hypertension.¹³

Immune System Function. CoQ10 has a modulating effect on the immune system¹⁴, and large doses have shown evidence of protection against a recurrence of breast cancer in high risk individuals.¹⁵

Dosage: Usual recommendations are 30 to 90 mg per day, in divided doses, taken with meals. More can be used for specific conditions, and doses of up to 400 mg per day are in the literature without significant side effects. For treatment of CHF, 2 mg per kilogram of bodyweight is the dosage associated with benefit. The oil-based, solubilized form (such as Q-sol) has been shown to have the greatest absorption.

Contraindications: There are no contraindications, but people with diabetes need to monitor blood sugar carefully, as glucose levels may go down with CoQ10 therapy.

People taking "statins" (cholesterol lowering drugs) and beta-blockers may be CoQ10 deficient, and should supplement.

People taking warfarin should have their protimes monitored carefully.

CoQ10 should not be stopped suddenly, as worsening symptoms of heart failure may occur.

References:
¹Weber C, Jakobsen TS, Mortensen SA, et al. Antioxidative effect of dietary coenzyme Q10 in human blood plasma. Internat J Vit Nutr Res 1994;64:311–15.
²Werbach MR. Nutritional Influences on Illness [book on CD-ROM]. Tarzana, Calif: Third Line Press; 1998.
³Morisco C, Trimarco B, Condorelli M, et al. Effect of coenzyme Q10 therapy in patients with congestive heart failure: a long-term multicenter randomized study. Clin Investig. 1993;71(suppl):S134–S136.
⁴Hashiba K, Kuramoto K, Ishimi Z, et al. Heart. 1972;4:1579–1589. Cited by: Werbach MR. Nutritional Influences on Illness [book on CD-ROM]. Tarzana, Calif: Third Line Press; 1998.
⁵Hofman-Bang C, Rehnquist N, Swedberg K, et al. Coenzyme Q10 as an adjunctive treatment of congestive heart failure. J Am Coll Cardiol. 1992;19:216A.
⁶Langsjoen H, Langsjoen P, Langsjoen P, et al. Usefulness of coenzyme Q10 in clinical cardiology: a long-term study. Mol Aspects Med. 1994;15(suppl):S165–S175.
⁷Langsjoen PH, Vadhanavikit S, Folkers K. Response of patients in classes III and IV of cardiomyopathy to therapy in a blind and crossover trial with coenzyme Q10. Proc Natl Acad Sci U S A. 1985;82:4240–4244.
⁸Pogessi L, Galanti G, Comeglio M, et al. Effect of coenzyme Q10 on left ventricular function in patients with dilative cardiomyopathy. Curr Ther Res. 1991;49:878–886.
⁹Kamikawa T, Kobayashi A, Yamashita T, et al. Effects of coenzyme Q10 on exercise tolerance in chronic stable angina pectoris. Am J Cardiol 1985;56:247.
¹⁰Mortensen SA. Perspectives on therapy of cardiovascular diseases with coenzyme Q10 (ubiquinone). Clin Invest 1993;71:s116–23 [review].
¹¹Imagawa M, Naruse S, Tsuji S, et al. Coenzyme Q10, iron, and vitamin B6 in genetically-confirmed Alzheimer’s disease. Lancet 1992;340:671 [letter].
¹²Digiesi V, Cantini F, Bisi G, et al. Mechanism of action of coenzyme Q10 in essential hypertension. Curr Ther Res 1992;51:668–72.
¹³Gaby AR. The role of coenzyme Q10 in clinical medicine: part II. Cardiovascular disease, hypertension, diabetes mellitus and infertility. Alt Med Rev 1996;1:168–75 [review].
¹⁴Folkers K, Shizukuishi S, Takemura K, et al. Increase in levels of IgG in serum of patients treated with coenzyme Q10. Res Comm Pathol Pharmacol 1982;38:335–38.
¹⁵Lockwood K, Moesgaard S, Yamamoto T, Folkers K. Progress on therapy of breast cancer with vitamin Q10 and the regression of metastases. Biochem Biophys Res Comm 1995;212:172–77.