Saturated, unsaturated, trans, omega-6, omega-3… Like the Eskimo languages famed for having dozens of words for ‘snow’, the modern Western vocabulary is rich in ways to describe fat—as well as advice on which ‘good’ and ‘bad’ fats to seek out or avoid for a healthy diet. But according to an exhaustive new meta-analysis, decades of clinical trials have shown no link between heart disease and saturated fat. In other words, the “bad” saturated fats found in meat and dairy carry no greater risk of heart disease than the “good” unsaturated fats found in nuts, seeds and vegetable oils. The only truly “bad” fats are the trans fats added to processed foods.

This comprehensive review, which was conducted by an international team of American, British and Dutch researchers and published in this week’s Annals of Internal Medicine, critically assessed the combined findings of all published clinical studies on different types of fatty acids in heart disease (over 70 studies involving more than 600,000 people). The only type of fat with a consistent link to heart disease was the trans fats. Saturated fats, which have been targeted as unhealthy by many public health recommendations, were not linked to an extra risk of heart disease. Furthermore, even within the same broad categories of fats, results were mixed, with some specific fats associated with small increases in risk while similar fats were associated with small decreases in risk. Overall, the results suggest that a balanced diet is what really matters to heart health, not the details of which fat we eat.

(Source: Annals of Internal Medicine, 2014; 160 (6): 398-406.)