Omega-3 fatty acid supplementation not associated with lower risk of major CVD events

In a study that included nearly 70,000 patients, supplementation with omega-3 polyunsaturated fatty acids was not associated with a lower risk of all-cause death, cardiac death, sudden death, heart attack, or stroke, according to an analysis of previous studies published in the September 12 issue of JAMA.

12 sept 2012--"Treatment with marine-derived omega-3 polyunsaturated fatty acids (PUFAs) for the prevention of major cardiovascular adverse outcomes has been supported by a number of randomized clinical trials (RCTs) and refuted by others. Although their mechanism of action is not clear, their postulated effect on cardiovascular outcomes may be due to their ability to lower triglyceride levels, prevent serious arrhythmias, or even decrease platelet aggregation and lower blood pressure. Current guidelines issued by major societies recommend their use, either as supplements or through dietary counseling, for patients after myocardial infarction [MI; heart attack], whereas the U.S. Food and Drug Administration has approved their administration only as triglyceride-lowering agents in patients with overt hypertriglyceridemia, and some (but not all) European national regulatory agencies have approved the omega-3 administration for cardiovascular risk modification. The controversy stemming from the varying labeling indications causes confusion in everyday clinical practice about whether to use these agents for cardiovascular protection," according to background information in the article.

Evangelos C. Rizos, M.D., Ph.D., of the University Hospital of Ioannina, Ioannina, Greece, and colleagues performed a large-scale synthesis of the available randomized evidence by conducting a systematic review and meta-analysis to determine the association between omega-3 PUFAs and major cardiovascular outcomes.

Of the 3,635 citations retrieved, 20 studies with 68,680 randomized patients were included, reporting 7,044 deaths, 3,993 cardiac deaths, 1,150 sudden deaths, 1,837 heart attacks, and 1,490 strokes. Analysis indicated no statistically significant association with all-cause mortality,cardiac death, sudden death, heart attack, and stroke when all supplement studies were considered.

"In conclusion, omega-3 PUFAs are not statistically significantly associated with major cardiovascular outcomes across various patient populations. Our findings do not justify the use of omega-3 as a structured intervention in everyday clinical practice or guidelines supporting dietary omega-3 PUFA administration. Randomized evidence will continue to accumulate in the field, yet an individual patient data meta-analysis would be more appropriate to refine possible associations related to, among others, dose, adherence, baseline intake, and cardiovascular disease risk group," the authors conclude.

More information: JAMA. 2012;308[10]:1024-1033.

Provided by JAMA and Archives Journals

DHA 'fish oil' supplements do not seem to slow cognitive, functional decline in Alzheimer's disease

Patients with mild to moderate Alzheimer's disease (AD) who received supplementation with the omega-3 fatty acid docosahexaenoic acid (DHA), believed to possibly reduce the risk of AD, did not experience a reduction in the rate of cognitive and functional decline, compared to patients who received placebo, according to a study in the November 3 issue of JAMA, a theme issue on aging.

06 nov 2010--"Several studies have found that consumption of fish, the primary dietary source of omega-3 fatty acids, is associated with a reduced risk of cognitive decline or dementia. Some studies have found that consumption of DHA, but not other omega-3 fatty acids, is associated with a reduced risk of Alzheimer disease," the authors write. However, those studies were observational and did not control who received DHA. Animal studies that used DHA showed reductions in Alzheimer-like brain pathology.

Dr. Quinn and colleagues conducted a randomized, controlled trial to examine whether DHA supplementation would slow the rate of cognitive and functional decline in individuals with Alzheimer's disease. The study, which was conducted between November 2007 and May 2009 at 51 U.S. clinical research sites, included 402 individuals with mild to moderate Alzheimer's disease. Participants were randomly assigned to DHA at a dose of 2 grams/day or to identical placebo (60 percent were assigned to DHA and 40 percent were assigned to placebo). Duration of treatment was 18 months. Changes in cognitive and functional abilities were assessed with the Alzheimer's Disease Assessment Scale

(ADAS-cog) and the Clinical Dementia Rating (CDR) sum of boxes. Rate of brain atrophy was also determined by volumetric magnetic resonance imaging (MRI) in a subsample of participants.

A total of 295 participants completed the trial while taking study medication (DHA: 171; placebo: 124). The researchers found that supplementation with DHA had no beneficial effect on rate of change on ADAS-cog score, with the rate of average change in the score over 18 months being 8.27 points for the placebo group and 7.98 points for the DHA group. The rate of points change on CDR sum of boxes over 18 months was 2.93 for the placebo group compared with 2.87 for the DHA group.

Among the individuals participating in the MRI substudy (102 had MRIs at the beginning of the study and at 18 months [DHA group: 53; placebo group: 49]), an analysis showed no effect of DHA treatment on total brain volume change during 18 months.

"In summary, these results indicate that DHA supplementation is not useful for the population of individuals with mild to moderate Alzheimer disease," the authors write.

The researchers add that "because part of the rationale for the trial was epidemiological evidence that DHA use before disease onset modifies the risk of Alzheimer disease, it remains possible that an intervention with DHA might be more effective if initiated earlier in the course of the disease in patients who do not have overt dementia."

More information: JAMA. 2010;304[17]:1903-1911.

Provided by JAMA and Archives Journals

Fish oil pills don't boost benefit of heart drugs

By MARILYNN MARCHIONE

ORLANDO, Fla., 31 mar 2009 – Heart attack patients who are already taking the right medicines to prevent future problems get no added benefit from taking fish oil capsules, a large study in Germany finds.

The study tested a 1-gram daily dose of a prescription version of highly purified omega-3 fatty acid — the "good fat" contained in certain oily fish that is thought to help the heart.

Researchers led by Dr. Jochen Senges of the University of Heidelberg gave fish oil or dummy capsules to more than 3,800 people who had suffered a heart attack in the previous two weeks. About 90 percent were already receiving all the medicines recommended to prevent a second attack, including aspirin, anti-clotting and cholesterol drugs.

After a year, it made no difference whether these patients took fish oil or dummy capsules. In both groups, fewer than 2 percent had suffered sudden cardiac death, 4 percent had another heart attack, and fewer than 2 percent had suffered a stroke.

If recent heart attack patients are already getting good care, "there is almost nothing you can do better on top of this" to further lower risk, Senges said. He presented the results Monday at an American College of Cardiology conference.

The research doesn't mean that fish oil is of no value, and the study didn't address whether it can help prevent heart disease in the first place, doctors said.

The prescription version used in the study, sold as Omacor and Lovaza in the United States and as Zodin in Europe, is a highly purified and standardized form, different from what many consumers buy off the shelf.

Omega-3 fatty acids also are found in wild oily fish such as salmon, tuna, mackerel, sardines and herring. Scientists think it raises HDL, or good cholesterol, lowers harmful fats called triglycerides and slows the growth of plaque that can clog arteries.

The American Heart Association recommends adults eat fish at least twice a week, said Alice Lichtenstein, a Tufts University nutrition professor and Heart Association spokeswoman. For people with heart disease, the association advises 1 gram of omega-3 a day.

"A modest, 3-ounce cooked salmon has a little more than a gram," she said.

Fish oil capsules are not for children or women who are pregnant or nursing, because the pills pose a bleeding risk. Taking more than 3 grams a day from supplements should only be done under a doctor's orders, the heart association warns. The capsules also should be stopped a week or so before surgery because of a risk of bleeding.

The German study shows that "we need to be a little more cautious about the prediction of individual benefit of any nutritional supplements," said Lichtenstein, who had no role in the research.

"We see this pattern — people are so willing to embrace the simple answer," as if it's possible "to crack a capsule over a hot fudge sundae" and undo the harm of harmful diets and lack of exercise, she said.