|
Fish oil -- helpful or harmful?
January 15, 2008Fish oil supplements may help some cardiac patients while harming others
Toronto, ON - Fish oil supplements may help some cardiac patients while harming others, suggests a new review of evidence compiled by St. Michael's Hospital and University of Toronto researchers.
In a systematic review of trials where patients with implantable cardioverter defibrillators used fish oil supplements, Dr. David Jenkins and Dr. Paul Dorian found significant differences among the trials, indicating fish oil may be beneficial to some patients while having a negative impact on others.
"Fish oils can have complex and varied effects on the heart," says Jenkins, a U of T Professor of Medicine who runs the Clinical Nutrition and Risk Factor Modification Centre at St. Michael's Hospital. "These effects include blocking cardiac ion channels, reducing fibrosis in response to mechanical stress, decreasing blood coagulation, and possibly altering immune function."
There is evidence from multiple large-scale population (epidemiologic) studies and randomized controlled trials that intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements can reduce the risk of death, heart attack and dangerous abnormal heart rhythms in people with known cardiovascular disease, as well as potentially slow hardening of the arteries and lower blood pressure slightly. But the evidence also shows high doses can have harmful effects, such as an increased risk of bleeding. Although benefits are proposed for alpha-linolenic acid, scientific evidence is less compelling and beneficial effects may be less pronounced.
The meta-analysis reveals that studies in different patient populations with different pathophysiologies and therapeutic regimens have all produced divergent results. However, more recent data suggests that particular caution should be exercised when analyzing data from certain subgroups, such as men with stable angina. The same may also be true for patients with implantable cardioverter defibrillators who have a history of ventricular tachycardia and who are not taking antiarrhythmic medications.
"Fish oils have promise as beneficial in cardiovascular disease but our work highlights our gaps in understanding and the need for more research," adds Dorian, a cardiologist at St. Michael's Hospital and U of T Professor of Medicine University of Toronto.
The review, which will appear in the January 15 edition of the Canadian Medical Association Journal, also indicates that further research and large randomized controlled trials are needed before long-chain omega-3 fatty acids are used in patients with heart failure and angina.
University of Toronto
"Fish oils can have complex and varied effects on the heart," says Jenkins, a U of T Professor of Medicine who runs the Clinical Nutrition and Risk Factor Modification Centre at St. Michael's Hospital. "These effects include blocking cardiac ion channels, reducing fibrosis in response to mechanical stress, decreasing blood coagulation, and possibly altering immune function."
There is evidence from multiple large-scale population (epidemiologic) studies and randomized controlled trials that intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements can reduce the risk of death, heart attack and dangerous abnormal heart rhythms in people with known cardiovascular disease, as well as potentially slow hardening of the arteries and lower blood pressure slightly. But the evidence also shows high doses can have harmful effects, such as an increased risk of bleeding. Although benefits are proposed for alpha-linolenic acid, scientific evidence is less compelling and beneficial effects may be less pronounced.
The meta-analysis reveals that studies in different patient populations with different pathophysiologies and therapeutic regimens have all produced divergent results. However, more recent data suggests that particular caution should be exercised when analyzing data from certain subgroups, such as men with stable angina. The same may also be true for patients with implantable cardioverter defibrillators who have a history of ventricular tachycardia and who are not taking antiarrhythmic medications.
"Fish oils have promise as beneficial in cardiovascular disease but our work highlights our gaps in understanding and the need for more research," adds Dorian, a cardiologist at St. Michael's Hospital and U of T Professor of Medicine University of Toronto.
The review, which will appear in the January 15 edition of the Canadian Medical Association Journal, also indicates that further research and large randomized controlled trials are needed before long-chain omega-3 fatty acids are used in patients with heart failure and angina.
University of Toronto
Fish Oil News and Current Fish Oil Events RSSOily fish can protect against RA, but smoking and psychosocial stress increase its risk
New data presented today at EULAR 2008, the Annual Congress of the European League Against Rheumatism in Paris, France, show that intake of oily fish is associated with a reduced risk of developing rheumatoid arthritis (RA), whereas psychosocial work stress and smoking can increase the risk of developing the condition.
Reducing intake of dietary fat prevents prostate cancer in mice
Scientists with UCLA's Jonsson Cancer Center and the Department of Urology have showed that lowering intake of the type of fat common in a Western diet helps prevent prostate cancer in mice, the first finding of its kind in a mouse model that closely mimics human cancer, researchers said.
Mayo Clinic proceedings highlights research about cardiovascular benefits of omega-3 fatty acids
Thousands of research studies have documented how the oils known as omega-3 fatty acids can benefit the cardiovascular system, particularly among people diagnosed with coronary artery disease.
Clinical depression raises risk of death for heart attack patients years after attack
Depressed heart attack patients have a higher risk for sudden death in the months following a heart attack. Now a team led by researchers from Washington University School of Medicine in St. Louis has found that the risk continues for many years.
Why fish oil is good for you
It's good news that we are living longer, but bad news that the longer we live, the better our odds of developing late-onset Alzheimer's disease.
New clinical data shows chromium picolinate improves cognitive function
Nutrition 21, Inc. (NASDAQ: NXXI), a leading developer and marketer of chromium-based and omega-3 fish oil-based nutritional supplements, today announced the results of a clinical study that showed daily supplementation with 1000 mcg of chromium as chromium picolinate improved cognitive function in older adults experiencing early memory decline. The results of the randomized, double-blind, placebo-controlled study were presented to the medical community at a neurological meeting.
Leading researchers to reveal comprehensive dos and don'ts for prostate cancer
Today at the Prostate Cancer Foundation's Annual Scientific Retreat, researchers will share new findings on how eating common foods such as tomatoes and fish, maintaining a healthy weight, and avoiding meats cooked at high temperatures may help prevent prostate cancer, and help men live healthier and longer after diagnosis.
New review suggests caution on drugs to raise 'good' cholesterol
With 40 percent of all heart attacks and related cardiovascular problems occurring in people who have low levels of so-called "good" cholesterol, researchers have long sought medications to increase the amount of this type of cholesterol in the body's circulation.
More fish oil, less vegetable oil, better for your health
Scientists have provided new evidence that using more fish oil than vegetable oil in the diet decreases the formation of chemicals called prostanoids, which, when produced in excess, increase inflammation in various tissues and organs.
High cholesterol diets modify gene expression in atherosclerosis
Scientists from the department of Biochemistry and Molecular Biology 1 of the University of Granada (Universidad de Granada) have proven that a high cholesterol diet causes changes in gene expression of chicken aortic smooth muscle cells at the early stages of an experimental atherosclerosis.
More Fish Oil News Articles
| © 2008 BrightSurf.com |