But wait a minute, why have I seen news headlines about omega-3 fatty acids preventing heart attacks? And why did my doctor tell me to take fish oil pills to protect my health?
That’s the beauty and the challenge of systematic reviews.
The beauty: Those news headlines were probably based on one study that found a connection between omega-3 fatty acids and the prevention of heart disease. The study may have found a direct association between taking fish oil pills and having fewer heart attacks or it may have found a relationship with an outcome related to cardiovascular health and inferred that changes in that outcome could lead to a reduction in heart attacks and strokes. By combining the results of many studies, CESH was able to see if these results were just a coincidence or part of a real trend.
The challenge: Evidence synthesis can only analyze studies that already exist. So, we can’t conclusively say that omega-3 fatty acids have no effect on cardiovascular disease. We can only say that after looking at all of the existing research, there’s little evidence that omega-3 fatty acids prevent heart attacks and strokes.