EPA/DHA 大量療法が ADHD注意欠陥多動性障害に効果あり
Fish Oils May Slow Genetic Aging in Heart Patients
New Research Suggests Omega-3s May Slow Aging on Genetic Level; Some Heart Doctors Skeptical
By JOHN McKENZIE
ABC News Medical Correspondent
Jan. 19, 2010
Heart disease patients have long been encouraged to eat more fish or take fish oil supplements containing omega-3 fatty acids. The reason? People who do, tend to live longer.
Now, some say a study out this evening in the Journal of the American Medical Association might explain why.
Specifically, the researchers behind the study report that for heart disease patients, omega-3 fatty acids may protect against death and illness by slowing biological aging.
However, the findings were met with skepticism from some cardiac experts who said the study had serious limitations.
In the study, Dr. Ramin Farzaneh-Far of the University of California San Francisco and colleagues followed more than 600 men with heart disease and found those taking the most omega-3 appeared "biologically younger" -- that is, the ends of their chromosomes, called telomeres, looked longer and healthier.
"Patients with the highest levels of omega-3 fish oils were found to display the slowest decrease in telomere length, whereas those with the lowest levels of omega-3 fish oils in the blood had the fastest rate of telomere shortening," Farzaneh-Far said. "This suggests that these patients were aging faster than those with higher fish oil levels."
Some doctors agreed that the findings seem interesting.
"Telomeres do help the body repair damage," said Dr. Stephen Kopecky, a cardiologist at the Mayo Clinic in Rochester, Minn., who was not involved with the study. "The longer they are, the more the damage repair that can occur."
"It's a risk-free way of potentially extending lifespan and reducing disability," said Dr. Michael Roizen, chief wellness officer of the Cleveland Clinic in Cleveland, Ohio.
Yet some cardiologists were quick to point out that the results are preliminary, and need to be replicated before physicians can use them in practice.
Since the study was observational and couldn't prove cause-and-effect, "we don't really know whether ingestion of omega-3 fatty acids resulted in this 'benefit,'" said Dr. Steven Nissen of the Cleveland Clinic. "It remains entirely possible that individuals who consume more fish also have other favorable healthy habits. ... The relationship between telomere shortening and cardiovascular health is not well established."
This concern was echoed in a statement by a spokeswoman for the National Heart, Lung and Blood Institute, who told ABC News that while the study "shows a possible association between omega-3 fatty acids and telomere length," it "does not show causation."
Is It the Telomeres?
Researchers aren't entirely sure how omega-3s stop telomeres from getting smaller. While studies have shown that omega-3s appear to be effective for patients with coronary artery disease, the underlying mechanisms are not well understood. They may protect against oxidative stress, which is a major driver of telomere shortening and aging.
But what cardiologists do know is that omega-3s have been shown to have effects on other factors that contribute to heart disease risk -- a benefit that some said may have little to do with telomeres.
"We have a very good explanation already for why omega-3 fatty acids have a protective effect on heart disease," said Dr. Cam Patterson of the University of North Carolina at Chapel Hill McAllister Heart Institute. "Omega-3 fatty acids have a potent positive impact on lipids that circulate in the blood stream and damage the heart. The effects of omega-3 fatty acids on lipids are still the best advertisement for their use to prevent heart disease."
Dr. Merle Myerson of Columbia University agreed.
"[The researchers] don't mention that omega-3 fatty acids lower triglycerides and non-HDL cholesterol, and stabilize cell membranes -- all of which may reduce risk for coronary artery disease and sudden cardiac death," Myerson said.
Regardless of the reasons for the benefit, the study's researchers said that the findings uphold recommendations for patients with heart disease.
"The results of our study underscore the recommendations of the American Heart Association, that patients with known coronary artery disease should be getting at least one gram a day of omega-3 fish oil," Farzaneh-Far said.
Kristina Fiore of MedPage Today contributed to this report.
Association of Marine Omega-3 Fatty Acid Levels With Telomeric Aging in Patients With Coronary Heart Disease
Ramin Farzaneh-Far, MD; Jue Lin, PhD; Elissa S. Epel, PhD; William S. Harris, PhD; Elizabeth H. Blackburn, PhD; Mary A. Whooley, MD
Context Increased dietary intake of marine omega-3 fatty acids is associated with prolonged survival in patients with coronary heart disease. However, the mechanisms underlying this protective effect are poorly understood.
Objective To investigate the association of omega-3 fatty acid blood levels with temporal changes in telomere length, an emerging marker of biological age.
Design, Setting, and Participants Prospective cohort study of 608 ambulatory outpatients in California with stable coronary artery disease recruited from the Heart and Soul Study between September 2000 and December 2002 and followed up to January 2009 (median, 6.0 years; range, 5.0-8.1 years).
Main Outcome Measures We measured leukocyte telomere length at baseline and again after 5 years of follow-up. Multivariable linear and logistic regression models were used to investigate the association of baseline levels of omega-3 fatty acids (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) with subsequent change in telomere length.
Results Individuals in the lowest quartile of DHA+EPA experienced the fastest rate of telomere shortening (0.13 telomere-to-single-copy gene ratio [T/S] units over 5 years; 95% confidence interval [CI], 0.09-0.17), whereas those in the highest quartile experienced the slowest rate of telomere shortening (0.05 T/S units over 5 years; 95% CI, 0.02-0.08; P < .001 for linear trend across quartiles). Levels of DHA+EPA were associated with less telomere shortening before (unadjusted β coefficient x 10--3 = 0.06; 95% CI, 0.02-0.10) and after (adjusted β coefficient x 10--3 = 0.05; 95% CI, 0.01-0.08) sequential adjustment for established risk factors and potential confounders. Each 1-SD increase in DHA+EPA levels was associated with a 32% reduction in the odds of telomere shortening (adjusted odds ratio, 0.68; 95% CI, 0.47-0.98).
Conclusion Among this cohort of patients with coronary artery disease, there was an inverse relationship between baseline blood levels of marine omega-3 fatty acids and the rate of telomere shortening over 5 years.
Author Affiliations: Division of Cardiology, San Francisco General Hospital (Dr Farzaneh-Far), Departments of Medicine (Drs Farzaneh-Far and Whooley), Biochemistry and Biophysics (Drs Lin and Blackburn), Psychiatry (Dr Epel), and Epidemiology and Biostatistics (Dr Whooley), University of California, San Francisco, and Veterans Affairs Medical Center (Dr Whooley), San Francisco; and Sanford Research/USD and Sanford School of Medicine, University of South Dakota, Sioux Falls (Dr Harris).
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