Reported
July 14, 2003
Carnitine:
Right Supplement, Wrong Reason? -- Web Column
By Jim
Brown, Ph.D., Ivanhoe Health Correspondent
(Ivanhoe Newswire) -- Researchers keep trying and manufacturers
keep hoping. They both want to prove that carnitine supplements
make their way into muscle tissue to burn fat, enhance performance,
and improve body composition. They may be looking may be looking
in the wrong place.
Jeff Volek, Ph.D., William Kraemer, Ph.D., and a group of exercise
scientists at the University of Connecticut conducted a study
to find out if carnitine supplements could reduce the stressful
effects of exercise and speed up the recovery process. They found
the answer in blood flow, not in muscle tissue.
"Ninety-nine percent of the research with carnitine has focused
on it as a supplement fat burner and performance enhancer,"
says Volek. "Theoretically, if you can burn fat, you conserve
glycogen and enhance performance. But most of the studies never
really showed that it burned more fat. Unlike taking creatine
and increasing its presence in muscles by 20 percent or 30 percent,
study after study has shown that it is difficult to increase muscle
carnitine level by taking supplements."
Carnitine is a protein-like substance found in red meat and other
foods. Although we take in up to 300 milligrams a day, the body
can produce its own supply. There is no dietary requirement for
carnitine. Its primary function is to transport fatty acids into
cells to be burned as energy.
First to Look Outside the Box
"We were the first to look outside the box on how carnitine
might work apart from the fat burning theory," explains Volek.
"We knew there was research showing that carnitine also plays
a role in vasodilation (expanding the size of blood vessels) and
controlling blood flow. So we decided to find out what would happen
if you were to have better blood flow due to carnitine supplements
and how that would affect exercise recovery."
Volek's team recruited ten participants who were similar in background,
health status, body size, and eating habits. All had participated
in a weight training program for at least one year. For three
weeks they were given two grams of L-carnitine a day. Then they
were put through an exercise routine of five sets of squats with
15 to 20 repetitions each. Immediately after and at regular intervals
up to three hours following the workout, blood samples were taken
and magnetic tests were conducted to measure the amount of muscle
damage and tissue repair. After a "wash out" period
to rid the body of the added carnitine, the participants were
given a placebo and put through the same exercise program and
follow-up tests. Here is what they found.
"We discovered that some of the markers of the stress response
caused by exercise were diminished," says Volek. "The
MRI exams showed that the percent of muscle disruption was significantly
greater when they took the placebo -- less when they took carnitine
supplements. Also, soreness ratings were significantly higher
after taking the placebo than after taking carnitine. We think
this happened because the carnitine accumulated in the cells that
line blood vessels, made them expand, and increased the blood
flow and the delivery of oxygen."
Implications for Exercisers
The UConn research was reported in the Journal of Physiology.
If it holds up to further investigations of different groups and
with a variety of exercises, the implications for exercisers and
athletes could be profound.
"Two grams of carnitine supplementation a day might be useful
as a substance to aid recovery between bouts of exercise,"
concludes Volek. "If there is less tissue damage and muscle
soreness, athletes can resume strenuous training sooner than they
have been able to in the past. That capacity, not fat burning,
could lead to better performance."
This
article was reported by Ivanhoe.com, who offers Medical Alerts
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