Replace saturated animal fats with unsaturated oils—that's what doctors generally tell people at risk for heart disease, and that's what the American Heart Association recommends. But what if this advice is dead (literally) wrong? That's the possibility raised by a study published in the British Medical Journal.
In a new analysis of a clinical trial involving middle-aged men with heart disease, those who replaced saturated animal fats with polyunsaturated vegetable fats were at increased risk of death, from cardiovascular disease, coronary artery disease and all causes.
These findings support the heart disease theories voiced by Paleo/Primal advocates like Chris Kresser and Mark Sisson, who say the industrial seed oils which dominate the American diet (such as sunflower, safflower, corn, soy and cottonseed) are too high in omega-6 polyunsaturated fatty acids, and that this promotes inflammation and heart disease. On the other end of the health-advice spectrum, vegan-leaning doctor Dean Ornish agrees that too much omega-6 fatty acids lead to heart disease (but unlike the Paleo advocates, he maintains that animal fats do too).
But for now the American Heart Association is sticking to the recommendation that we eat vegetable oils and soft margarine as our fat sources.
So, should you pay attention to this study and start cooking with butter instead of canola oil, or put your trust in the Heart Assocation's recommendations?
That's probably the wrong question to ask. Instead of worrying about what fats to cook with at home, I recommend taking this study as another reminder to eat less processed and packaged food. Every cardboard box and plastic bag lining the center rows of the supermarket lists polyunsaturated oils as a main ingredient, and fast food is loaded with them. Avoiding fast food and processed snack food is something that everybody can agree is heart-healthy.
More about which fats are good fats: