Why Aging Humans Need More Carnitine
By Julius G. Goepp, MD
An inevitable consequence of aging is a rapid decline in our cellular energy levels. The outward effects often manifest as a sense of overall fatigue, depression, and sexual dysfunction. The internal effect of a cellular energy deficit is a greater vulnerability to a host of degenerative diseases.
The prime reason cells lose their energy-producing ability is that the powerhouses of the cells—the mitochondria—become dysfunctional. Research has shown that the amino acid carnitine is critical to maintaining optimal mitochondrial function and supporting high energy production.
Carnitine is responsible for fueling the fires of energy production at the cellular level. Without this valuable nutrient, the mitochondria are unable to burn dietary fats to create the energy we need to live.
Scientists have discovered several different forms of carnitine that, in addition to bolstering energy production, produce health benefits that include protecting against neurodegenerative diseases, alleviating depression, stimulating nerve growth, and improving heart function.
Why Carnitine Supplementation Is Essential
During one’s youth, most of the body’s requirement for carnitine is met by internal production of carnitine from lysine, as well as by dietary sources such as red meat and dairy products.1 An increasing body of evidence, however, indicates that to obtain enough carnitine to secure its protective effects against aging requires supplementation in addition to dietary sources.2
While scientific studies initially focused on the simplest form of carnitine, known as L-carnitine, recent findings suggest that specialized carnitine formulations may provide more dramatic, tissue-specific benefits.3
Acetyl-L-carnitine is the most widely studied carnitine supplement. It readily crosses the blood-brain barrier4 and thus confers powerful protective effects on nerve tissue and the central nervous system—enhancing mood, restoring energy, and alleviating nerve pain.
A closely related compound, acetyl-L-carnitine arginate, combines carnitine with the amino acid arginine. It appears to have the same general properties as acetyl-L-carnitine, with the additional benefit of increasing nerve cell growth, thus making it a promising agent in addressing neurodegenerative conditions and possibly trauma.
Finally, propionyl-L-carnitine is a form of carnitine that appears to have potent effects in cardiac and skeletal muscle,3 giving it a potential role in maintaining physical energy and stamina.
This article will examine the complementary roles of these different forms of carnitine and how readers can select carnitine supplements to address their specific health concerns associated with aging.
Acetyl-L-Carnitine Benefits Brain and Nerve Function
Because acetyl-L-carnitine is absorbed from the intestinal tract and readily crosses the blood-brain barrier,4,10,11 it has been studied extensively for its role in brain and nerve functions. Some of the most compelling data are summarized here, according to the kinds of conditions involved.
Slowing Alzheimer’s and Neurodegenerative Diseases
Our brains require vast amounts of energy to function on a daily basis. The long-term effect of this high energy consumption is a kind of “brain rust,” or oxidative damage to mitochondria in th