People given omega-3 fish oil supplements in randomized clinical trials were at lower risk of heart attack and other cardiovascular disease (CVD) than those given placebo. This was the result of a new meta-analysis from the Harvard TH Chan School of Public Health and Brigham and Women’s Hospital.
The researchers found an association between daily omega-3 supplementation and the reduced risk of most CVD outcomes, including heart attack, death from coronary artery disease, and death from CVD, but saw no benefit for stroke. In addition, higher doses of omega-3 fish oil supplements seemed to provide even greater risk reduction.
The study was published online today in the Journal of the American Heart Association.
“This meta-analysis provides the most up-to-date evidence of the effects of omega-3 supplementation on the risk of multiple CVD outcomes. We found significant protective effects of daily omega-3 supplementation against most CVD outcome risks, and the associations appeared to be dose-dependent, ”said first author Yang Hu, a postdoctoral fellow in the Department of Nutrition at Harvard Chan School.
While observational studies have shown an association between fish consumption and lower risk of heart disease, the results of randomized controlled trials have been inconsistent. Two reviews published last year did not provide any clear indications of any benefit.
In this new analysis, the researchers performed an updated meta-analysis that included three recently completed large-scale studies that increased the sample size by 64 percent. The total population analyzed by Hu and colleagues included more than 120,000 adults in 13 randomized studies worldwide. The analysis included the VITAL study, the largest randomized study to date with omega-3 fatty acids.
The results showed that people who took omega-3 fish oil supplements daily, compared to those who took a placebo, reduced their risk for most CVD outcomes except for stroke, including an 8 percent reduced risk of heart attack and Death from coronary artery disease (CHD)). The association was particularly evident with higher doses of an omega-3 fish oil supplement. This finding could suggest that doses of marine omega-3 supplementation above 840 mg / day, which is used in most randomized clinical trials, may be more effective in reducing the risk of CVD. Given that several million people worldwide are affected by these CVD events each year, the researchers say that even small risk reductions can result in hundreds of thousands of heart attacks and avoided CVD deaths.
“Although public health recommendations should focus on increasing fish consumption, eating a heart-healthy diet, physical activity and other healthy lifestyle habits, this study suggests that omega-3 supplementation may play a role in eligible patients,” said senior writer JoAnn Manson, director of the preventive medicine department at Brigham and Women’s Hospital and professor in the epidemiology department at Harvard Chan School. Manson is also the director of the large-scale VITAL study.
Other authors from Harvard Chan School were Frank Hu.
VITAL was supported by grants U01 CA138962 and R01 CA138962 from the National Institutes of Health. Pharmavite LLC from Northridge, California (vitamin D) and Pronova BioPharma from Norway as well as BASF (Omacor fish oil) donated the study funds and the corresponding placebos.