Consumption of trans unsaturated fats, as opposed to saturated fats, is associated with greater risk of death and coronary heart disease, according to a meta-analysis published online ahead of print August 12 in BMJ. 


Lead author Russell de Souza, MSc, ScD, and colleagues analyzed the results of 50 observational studies on intake of dietary fats and health outcomes in adults. They found that trans fats were associated with an increase of 34% in death from any cause, an increase of 28% in death due to coronary heart disease (CHD), and an increase of 21% in the risk for CHD. In contrast, saturated fats were not associated with all-cause mortality, cardiovascular disease (CVD), CHD, ischemic stroke, or type 2 diabetes. Due to inconsistencies in the studies analyzed, the researchers said they could not confirm an association between trans fats and ischemic stroke or between trans fats and type 2 diabetes. 


The authors noted that the evidence for their conclusions on saturated fats is heterogeneous with methodologic limitations, and their data on trans fats may be the result of greater consumption of industrial, instead of ruminant, trans fats. 


“Trans fats have no health benefits and pose a significant risk for heart disease, but the case for saturated fat is less clear,” said Dr. de Souza. “That said, we aren’t advocating an increase of the allowance for saturated fats in dietary guidelines, as we don’t see evidence that higher limits would be specifically beneficial to health.


“If we tell people to eat less saturated or trans fats, we need to offer a better choice,” he continued. “Unfortunately, in our review, we were not able to find as much evidence as we would have liked for a best replacement choice, but ours and other studies suggest replacing foods high in these fats, such as high-fat or processed meats and donuts, with vegetable oils, nuts, and whole grains.”