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Thursday, October 23
11-11:50am
Location: Casanova 605
The Basic Science of Omega-3 Fatty Acids
The cardio-protective properties of the long-chain omega-3 fatty
acids found in fish oils have become more clear in recent years. Intakes
of 500 to 1,000 mg/d, either from food or supplements (as recommended by
the American Heart Association) have been generally associated with
significantly reduced risk for coronary heart disease events, in
particular, sudden cardiac death. Low intakes or blood levels of
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are
independently associated with increased risk of death from coronary
heart disease (CHD). The mechanism by which low doses of omega-3 FA (500
to 1,000 mg/d) reduce risk for fatal events is not clear, but may
involve reducing the heart rate. Similarly, the biochemical basis for
their beneficial effects are as yet unknown, but possibilities include
alteration of membrane structure and function, modulation of
transcription factors, increased plaque stability, and changes in
eicosanoid metabolism. Red blood cell (RBC) fatty acid composition
reflects long-term intake of EPA+DHA. It is proposed that the RBC
EPA+DHA (hereafter called the Omega-3 Index) may be a new risk factor
for death from CHD. When the relationship between this putative marker
and risk for CHD death was evaluated using published primary and
secondary prevention studies, an Omega-3 Index of approximately 8
percent was associated with the greatest cardio protection, whereas an
Index of less than 4 percent was associated with the least. Preliminary
data now suggests that the Omega-3 Index may be a risk marker, not just
for CHD fatality, but also for acute coronary syndromes. The Omega-3
Index may represent a novel, physiologically-relevant, easily-modified,
independent and graded risk factor for both CHD events and for death
from CHD that could have significant clinical utility.
Speaker:
 William S. Harris, Ph.D., is currently a
research professor of medicine and the director of the Nutrition and
Metabolic Disease Research Center at Sanford Research/USD and the
Sanford School of Medicine at the University of South Dakota in Sioux
Falls, Iowa. He holds a doctorate in nutritional biochemistry
from the University of Minnesota. He did postdoctoral fellowships in
Clinical Nutrition and Lipid Metabolism at the Oregon Health Sciences,
and became director of the Lipid Research Laboratory at the Kansas
University Medical Center and at the University of Missouri-Kansas City
School of Medicine. Over the last 25 years, Dr. Harris’s research has
focused primarily on fish oils (omega-3 fatty acids) and cardiovascular
disease. He has been the principal investigator on three NIH grants
focusing on omega-3 fatty acids and human lipid metabolism, and is
currently studying the combined effects of Lovaza (previously Omacor)
and Niaspan in patients with the metabolic syndrome. Dr. Harris has also
been exploring the potential value of red blood cell omega-3 fatty acid
levels (i.e., the omega-3 index) as a new risk factor for cardiovascular
disease. He has over 120 peer-reviewed publications.
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