I just love the science of nutrition. It constantly changes as we learn more about how food and nutrients work in the body. And as we gather more information, experts tweak the recommendations for how we should eat.
Take the egg, for example. In 1968, the American Heart Association looked at the evidence that seemed to show that a high intake of cholesterol in food (such as eggs) increased blood cholesterol and therefore one’s risk for heart disease. That led to a long-standing recommendation to limit our egg intake to no more than three a week.
It took 47 years for the humble egg to be vindicated. After reviewing all the evidence through those years, a committee of experts in 2015 reversed the old recommendation to limit eggs in the diet. There was no basis, they reported, to limit eggs as a way to decrease heart disease.
Now a battle seems to be brewing over saturated fat. While a preponderance of research studies validate the unhealthy role of saturated fat in the diet, other studies suggest another story.
For example, experimental studies on mice and men have shown eating a diet high in saturated fat produces an inflammatory response in the body. Diseases like obesity, Type 2 diabetes and heart disease are known to be inflammatory conditions. Hence the general recommendation to reduce our intake of saturated fats.
Not all saturated fat behaves the same, however. Stearic acid, for example, is the primary saturated fat in cocoa. Yet it has no effect on blood cholesterol levels or heart disease risk.
Saturated fats may even act differently depending on what foods they inhabit. For instance, even though at least 60 percent of the fat in dairy food is the saturated type, recent studies have found full fat milk products do not seem to increase the risk for heart disease or Type 2 diabetes. In fact, a huge prospective study from 21 countries in 2018 concluded at least two daily servings of dairy foods (regardless of fat content) was associated with a lower risk of heart disease and stroke.
What gives? There is still good evidence that we can reduce our risk for heart disease by replacing some of the saturated fat in our diets with unsaturated fats, like those found in vegetable oils. That is the recommendation from the experts who drafted the most current 2020-2025 Dietary Guidelines for Americans.
I was intrigued, however, that the latest recommendations from the Heart and Stroke Foundation in Canada does not place a limit on saturated fat. Here’s what they said:
“The science of nutrition is ever-evolving with new evidence emerging all the time. It is becoming increasingly clear that what has the most impact on health is the overall quality of one’s diet, combined with the quantity of food consumed.”
What will be the final take on the role of saturated fat in our diet? Perhaps we are learning (again) that nutrition is not all or nothing. Stay tuned …