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Last Updated: Apr 16, 2008 - 5:52:06 PM |
A
compound found in oil-rich fish such as salmon reshaped the blood lipid
profiles of volunteers in an Agricultural Research Service-led study.
Research
chemist Darshan S. Kelley of the ARS Western Human Nutrition Research
Center in Davis, Calif., and federal and university co-investigators
conducted the study of DHA, or docosahexaenoic acid, a polyunsaturated
fatty acid thought to improve cardiovascular health.
The
research, reported earlier this year in the American Journal of
Clinical Nutrition, is likely the first to analyze--in
high-triglyceride males--DHA's effects on both fasting and post-meal
triglycerides, and on quantities and sizes of HDL, LDL and VLDL
cholesterol particles. High triglycerides, high cholesterol and a high
number of small particles of LDL cholesterol in the blood increase risk
of cardiovascular disease, the nation's leading cause of death,
according to Kelley.
The study is also one of only about a
dozen, in humans, to probe the effects of DHA alone, rather than in
tandem with another natural oil, EPA, or eicosapentanoic acid. EPA
occurs with DHA in fish oil.
Half of the study’s 34 volunteers,
age 39 to 66, consumed about one-half teaspoon of DHA daily, in
addition to regular meals, for 90 days. The other half received olive
oil in place of DHA oil.
Blood samples taken after fasting, and
within eight hours after meals, showed that DHA reduced by 22 percent
the number of small LDL (low-density lipoprotein) particles. LDL’s
small particles are the size most harmful to the cardiovascular system.
DHA increased the number of large LDL particles by 127 percent. Since
large LDL particles are less harmful than small ones, some researchers
believe large LDL particles do not harm the arteries.
DHA also
lowered triglycerides by 24 percent in both the fasting and post-meal
samples. The after-meal effect, shown in only a few other studies, may
be of particular interest to medical professionals looking for
alternatives to conventional triglyceride-lowering therapies, according
to Kelley.
ARS is the U.S. Department of Agriculture's chief scientific research agency.
______________________________
ARS News Service
Agricultural Research Service, USDA
Marcia Wood, (301) 504-1662, marcia.wood@ars.usda.gov
December 3, 2007
--View this report online, plus photos and related stories, at www.ars.usda.gov/is/pr
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© 2004-2008 by foodconsumer.org unless otherwise specified
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