L-carnitine is an important amino acid that helps the body to utilize fats as fuel. Technically, L-carnitine is the amino acid that ferries fatty acids to the mitochondria of the cell, where they can be made into ATP (cell fuel.)It is derived in the body from L-lysine, and methylated with the help of L-methionine (SAMe) into L-carnitine. This is a great example of how the body can make its own amino acids from the 8 “essential” amino acids. L-Carnitine is found in beef and lamb, and in much smaller amounts in milk, avocado, tempeh, wheat, and peanut butter. Because the body can make its own reserves, vegans and vegetarians have not been found to be deficient as levels are not related to dietary intake. Recent studies supplementing aged rats illustrated that taking alpha-lipoic acid with L-carnitine further improved mitochondrial function, improved memory and decreased cellular aging.
Uses: This conditionally essential amino acid has a valuable role in many multiple body systems that require significant fuel sources including the heart, peripheral nerves, the arteries, the brain, and semen. It may be used by athletes to improve endurance, fat burning and energy production during exercise and speed muscle recovery; however, small uncontrolled studies have shown no clinical effect on physical performance or weight loss.
A recent focus of study has been on L-carnitine and male fertility. L-carnitine is concentrated in the male epididymis where sperm mature and become mobile. A daily dose of 3000mg of L-carnitine per day for 4 months significantly improved sperm motility in men struggling with this issue. (1) In another study, 2000mg per day for 2 months was positively correlated with improved sperm count, percent motility and percent normal sperm, exhibiting the important relationship between L-carnitine and sperm health. (1)
L-carnitine is also lost in kidney hemodialysis and end-stage renal disease, and has been approved by the FDA for treatment and prevention of L-carnitine deficiency related to this condition. Associated symptoms like persistent muscle cramps, weakness, low blood pressure and anemia can be helped with this supplement.
Antiretroviral HIV medications also deplete valuable L-carnitine, contributing to peripheral neuropathy.
There is reliable clinical evidence that L-carnitine can be helpful when used alongside appropriate medical therapies for individuals suffering from heart attacks, heart failure, angina and intermittent claudication. Because this amino acid can assist in transporting the valuable fuel sources to the cells that need it, heart muscle cells can have improved endurance and recover from damage more effectively with the addition of L-carnitine to a medical treatment regime. The dosages in studies have varied from IV use of L-carnitine to 2000-6000mg daily oral doses.
Forms: L-carnitine can be purchased as a capsule or liquid. L-acetylcarnitine is another form that may be absorbed better, and is the most researched form for anti-aging, brain/nerve and fertility support. It has all the same functions as L-carnitine, while having slightly different biochemistry. Propionyl-L-carnitine is the most researched therapeutic form for arterial conditions including angina.
Side effects: Greater than 3,000mg per day has been associated with a “fishy” body odor. Rare nausea, diarrhea and cramping have been reported.
Contraindications: L-carnitine has been shown to increase seizure disorders, and should be avoided if necessary. Do not use the D-carnitine form, as only the L-carnitine form has a beneficial effect on health and wellness.
Drug Nutrient Interactions: Carnitine may interfere with thyroid function and is not recommended for low thyroid patients; however, it may be helpful in hyperthyroidism. L-carnitine may be depleted by the following medications, and supplementation may be indicated: isotretinoin retinoids, long term pivampicillin or pivalate prodrugs, simvastatin/statins, AZT and other antiretrovirals.
References:
1. “L-Carnitine.”Micronutrient Information Center. Linus Pauling Institute, 2012. http://lpi.oregonstate.edu/mic/dietary-factors/L-carnitine Accessed April 21 2015
“This link leads to a website provided by the Linus Pauling Institute at Oregon State University. Coastal Pharmacy & Wellness is not affiliated or endorsed by the Linus Pauling Institute or Oregon State University.”
2. “L-Carnitine – Is it Good or Bad for your Heart?” Hammer Nutrition. n.d, n.p, http://www.hammernutrition.com/knowledge/l-carnitine-is-it-good-or-bad-for-your-heart.17139.html?sect=blog-section Accessed 21 April 2015
3. “Carnitine (L-carnitine)” Complementary and Alternative Medicine Guide. University of Maryland Medical Center. March, 2011 http://umm.edu/health/medical/altmed/supplement/carnitine-lcarnitine Accessed 21 April 2015
4. Stargrove M, Treasure J, McKee D. Mosby Herb, Nutrient and Drug Interactions. Missouri: Elsevier Publishing, p.661, 664-670
5. Balercia, Giancarlo MD, Regoli, Francesco Ph.D., Armeni, Tatiana Ph.D, Koverech, Aleardo M.D., Mantero, Franco M.D., Boscaro, Marco M.D.”Placebo-Controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-caetylcarnitine in men with idiopathic asthenozoospermia.” Fertility and Sterility 84.3 (2005): 662-671 http://www.fertstert.org/article/S0015-0282%2805%2901230-6/fulltext Accessed 24 April 2015
6. Gropper, Susan, Smith, Jack, Groff, James. Advanced Nutrition and Human Metabolism. Belmont, CA: Wadsworth 2005 p. 189-90
About the Author
Dr. Masina Wright
