Alzheimer's Disease and Carnitine

Carnitine is a substance used by the body uses to turn fat into energy. It is not normally considered an essential nutrient because the body can manufacture all it needs. However, supplemental carnitine could in theory improve the ability of certain tissues to produce energy. This has led to the use of carnitine for various muscle diseases as well as heart conditions. A form of Carnitine, Acetyl-L-Carnitine, is used to treat patients with Alzheimer's. Studies have shown greater improvement in patients with mild Alzeheimer's and patients who develop the health challenge at an earlier age.⁷²

Acetyl-L-Carnitine is a substance used by the body uses to turn fat into energy. Acetyl-L-Carnitine, in theory, could improve the ability of certain tissues to produce energy, including brain tissue that is impacted in patients with Alzheimer's disease.

Read more details about Carnitine.

Numerous double- or single-blind studies involving a total of more than 1,400 people have evaluated the potential benefits of acetyl-L-carnitine in the treatment of Alzheimer's disease and other forms of dementia.^40-48,76-78 However, while early studies found evidence of modest benefit, two large and well-designed studies failed to find acetyl-L-carnitine effective at all.

The first of these was a double-blind, placebo-controlled trial that enrolled 431 participants for 1 year.⁴⁷ Overall, acetyl-L-carnitine proved no better than placebo. However, because a close look at the data indicated that the supplement might help people who develop Alzheimer's disease at an unusually young age, researchers performed a follow-up trial. This 1-year, double-blind, placebo-controlled trial evaluated acetyl-L-carnitine in 229 patients with early onset Alzheimer's.⁴⁸ Unfortunately, no benefits were seen here either.

One review of the literature concluded that acetyl-L-carnitine may be helpful for mild cases of Alzheimer’s disease, but not more severe cases.⁷²

The principal dietary sources of carnitine are meat and dairy products, but to obtain therapeutic dosages a supplement is necessary. Typical adult dosages for the diseases described here range from 500 mg to 1,000 mg three times daily of Acetyl-L-Carnitine, which is the most beneficial in Alzheimer's cases.

Safety Issues

L-carnitine in its three forms appears to be quite safe. However, individuals with low or borderline-low thyroid levels should avoid carnitine because it might impair the action of thyroid hormone. ¹ Individuals on dialysis should not receive this (or any other supplement) without a physician's supervision.

The maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.

Interactions You Should Know About

If you are taking:

• Antiseizure medications, particularly valproic acid (Depakote, Depakene) but also phenytoin (Dilantin) : You may need extra carnitine.

• Thyroid medication: Do not take carnitine except under a physician's supervision.

1. Benvenga S, Lakshmanan M, Trimarchi F. Carnitine is a naturally occurring inhibitor of thyroid hormone nuclear uptake. Thyroid. 10(12):1043-50.

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72. Montgomery SA, Thal LJ, Amrein R. Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer's disease. Int Clin Psychopharmacol. 2003;18:61-71.

76. Rai G, Wright G, Scott L, et al. Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia. Curr Med Res Opin. 1990;11:638-647.

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