L-carnitine and LDL Cholesterol
A study published in a 2009 issue of the "American Journal of Clinical Nutrition" examined the effects of L-carnitine supplementation on oxidized low-density lipoprotein, or LDL cholesterol, in diabetics. The study used 81 people who had Type 2 diabetes and lasted about three months. The people were divided into two groups, and the results showed that those treated with L-carnitine displayed reduced oxidized LDL levels. Triglyceride levels decreased as well. This suggests that L-carnitine can manage cholesterol levels. However, more research is needed to verify this assertion.
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The Bad Side of L-Carnitine
In your stomach, L-carnitine is converted to a substance called trimethylamine or TMA, according to a study in the December 2013 issue of "Atherosclerosis." TMA is then sent to your liver where it is processed into trimethylamine-N-oxide, or TMAO. Researchers report that TMAO leads to the buildup of plaque in your arteries where it can cause heart disease, heart attack and stroke. The research on L-carnitine's negative effects on the heart has caused cardiologists to change their tune on L-carnitine in diet and supplementation. Doctoroz.com reports that while at one time he recommended L-carnitine, he no longer promotes its use in light of new evidence. L-carnitine is found in several foods, including pork, chicken and seafood, but it is found in the highest concentration in red meat. Doctor Oz recommends that you do not use L-carnitine as a supplement, and if you eat red meat limit your consumption to 4 ounces per week.