Lipoic Acid Found to Reduce Triglycerides by 60
Percent in Lab Rats
Follows study finding this cardiovascular risk is
common among U.S. adults
The blood plasma of obese rats fed a
normal diet is murky with higher levels of fat in the vial at
left, and much clearer with lower levels of triglycerides in the
vial on the right, which is plasma from rats supplemented with
lipoic acid.
April 1, 2009 Following only days after a study
in the Archives of Internal Medicine finds high concentrations of
triglyceride blood fats are common in the U.S., a new study finds that
supplementing the diets of lab rats with lipoic acid significantly
lowered their triglycerides. Researchers suggest it may be an easy way
to lower this risk of cardiovascular disease.
Triglycerides, along with cholesterol levels and blood
pressure, are one of the key risk factors in cardiovascular disease.
In the lab animals, supplements of lipoic acid
lowered triglyceride levels up to 60 percent. If the effect were the
same in humans which is not yet clear that would be a greater impact
than found with other dietary supplements, and similar to the effects of
some prescription drugs.
The results were just published in the Archives
of Biochemistry and Biophysics, a professional journal.
"The extent of triglyceride reduction was really
dramatic, we didn't expect it to be this profound," said Regis Moreau,
an assistant professor with the Linus Pauling Institute at Oregon State
University. "The potential is good that this could become another way to
lower blood triglycerides and help reduce the risk of atherosclerosis.
It's pretty exciting."
Lipoic acid is a natural
compound found at low levels in some foods, including red meat and green
leafy vegetables. A powerful antioxidant, it's been of considerable
research interest in recent years for its apparent ability to reduce
mitochondrial decay in cells and perhaps slow the process of aging. And
it's been used in Europe for decades as a treatment for the neuropathic
complications of diabetes.
More About Lipoic Acid
Alpha-lipoic acid (ALA, also known as lipoic acid
or thioctic acid) is an antioxidanta substance that protects against
cell damage. ALA is found in certain foods, such as liver, spinach,
broccoli, and potatoes. Some people with type 2 diabetes take ALA
supplements in the hope of lowering blood glucose levels by improving
the body's ability to use insulin; others use ALA to prevent or treat
diabetic neuropathy (a nerve disorder). Supplements are marketed as
tablets or capsules.
● ALA has been researched for its effect on
insulin sensitivity, glucose metabolism, and diabetic neuropathy. Some
studies have found benefits, but more research is needed. (There are
some studies, reported from outside the United States, of ALA delivered
intravenously; however, this research is outside the scope of this fact
sheet.)
● Because ALA might lower blood sugar too much,
people with diabetes who take it must monitor their blood sugar levels
very carefully.
"Lipoic acid is known to influence glucose uptake,
and bring down blood glucose by increasing its transport into skeletal
muscle," Moreau said. "Less has been done to study its potential value
in reducing triglycerides."
Until about 10 years ago, Moreau said, high blood
levels of triglycerides basically a form of fat were not thought to
be as significant as cholesterol at predicting atherosclerosis and heart
disease.
That perspective has changed, he added, and most experts now
see triglycerides as a third important risk factor for atherosclerosis,
along with levels of "good" HDL and "bad" LDL cholesterol.
Widely prescribed medications are often taken to
influence all of these issues, especially when efforts to control them
with diet, exercise, and proper weight have not been effective. However,
some of these medications have unwanted side effects that remain a
concern.
In this research, it was found that supplements of
lipoic acid appeared to affect triglyceride levels through two pathways.
After eating, lipoic acid supplementation increased the rate of
disappearance of triglycerides in the bloodstream. And supplements also
reduced the genetic expression of enzymes in the liver that synthesize
triglycerides.
This is the first study that has identified the
molecular targets by which lipoic acid can lower triglyceride levels,
the researchers said, and to show the effect on liver enzymes resulting
in less production of triglycerides. It also found that the mechanism of
action of how lipoic acid can lower triglycerides appears separate and
distinct from that provided by fibrate drugs, a group of prescription
medications often used for that purpose.
Lipoic acid supplements have in various studies
been shown to be an appetite suppressant, but control groups of
laboratory animals were used in this research to ensure that lower
triglyceride levels were not the result simply of less food intake.
The rats used in the experiment were obese to begin
with, and developed higher triglyceride levels as the experiment
proceeded and they aged but the animals given lipoic acid fared much
better. As they grew from five weeks of age to nine weeks, the blood
triglyceride levels doubled in rats given the supplement, but went up
more than 400 percent in the other group not given supplements.
The amount of lipoic acid supplementation used in
these laboratory experiments would equate to about two grams per day for
a 150-pound person, researchers said. Lipoic acid has been used by some
people for years as a dietary supplement and found to be safe, Moreau
said.
Tory Hagen, a principal investigator and holder of
the Jamieson Endowed Chair in Healthspan Research at the Linus Pauling
Institute, was a co-author on this study. The work was supported by the
National Institutes of Health and the National Center for Complementary
and Alternative Medicine.
"We believe that a novel means of controlling
triglyceridemia in this animal model has been revealed," researchers
wrote in their report. "Given its strong safety record, lipoic acid may
have therapeutic applications for the treatment or prevention of
hypertriglyceridemia and diabetic dyslipidemia in humans."
Lipoic Acid Could
Reduce Triglycerides, Atherosclerosis, Weight Gain
Another
study done with mice in January of 2008 discovered that supplements of
lipoic acid can inhibit formation of arterial lesions, lower
triglycerides, and reduce blood vessel inflammation and weight gain --
all key issues for addressing cardiovascular disease.
Although the results cannot be directly extrapolated beyond the
laboratory, researchers report that "they strongly suggest that lipoic
acid supplementation may be useful as an inexpensive but effective
intervention strategy reducing known risk factors for the development of
atherosclerosis and other inflammatory vascular diseases in humans."
The
findings were made by scientists from the Linus Pauling Institute and
College of Veterinary Medicine at Oregon State University, and the
Department of Medicine at the University of Washington.
The
study found that lipoic acid supplements reduced atherosclerotic lesion
formation in two types of mice that are widely used to study
cardiovascular disease, by 55 percent and 40 percent, respectively. The
supplements were also associated with almost 40 percent less body weight
gain, and lower levels of triglycerides in very low-density
lipoproteins.
As a
result, the authors concluded that "lipoic acid may be a useful adjunct
in the prevention and treatment of atherosclerotic vascular diseases."
