Is butter back? Cheese? What about your whole-milk yogurt? Emerging research suggests that the answers to these questions are no, yes and yes – with some caveats.
Full-fat milk, also known as whole milk, has a bad reputation because it contains saturated fat, and saturated fat raises LDL – or “bad” – cholesterol. But when looking at associations between actual dairy fat and health, results are mixed. That’s why, despite continuing to recommend limiting saturated fat, the Dietary Guidelines Advisory Committee in 2015 called for more research examining the effects of saturated fats from different food sources, because they may affect cholesterol and health differently.
Consider a recent study, published in July in the American Journal of Clinical Nutrition. It measured blood levels of three fatty acids known to correspond with dairy fat intake in 2,907 adults ages 65 and older. Researchers took samples at baseline, then six and 13 years later. All participants were free from cardiovascular disease at the start of the study. Over 22 years of followup, 2,228 participants died from various causes, but researchers found no significant links between long-term intake of dairy fat and any cause of death, including from heart disease or stroke. In fact, one type of saturated fatty acid in dairy was associated with lower risk of stroke-related death.
This study lends support to the general findings of long-term observational studies that dairy foods either reduce risk of cardiovascular disease and diabetes or simply have no effect. That includes higher fat as well as lower fat dairy. Because observational studies have limitations – people might not report their dietary habits accurately, or they may change after that information is collected – controlled studies such as clinical trials that closely monitor diet or use blood biomarkers as “evidence” of actual intake will be important pieces of the research puzzle, especially those that directly compare full-fat and lower-fat dairy foods.
For decades, dietary recommendations have been based on nutrients in food, not on foods themselves. That includes dairy foods, which are an important source of some nutrients that many Americans don’t get enough of, such as calcium and vitamin D. Because we need these other nutrients, the recommendation in the U.S. Dietary Guidelines has been to consume low-fat dairy.
But the studies cited above suggest that any negative effects of saturated fats on cardiovascular health may be neutralized when they are eaten as part of the complex “food matrix” formed by cheese and other dairy foods.
Whole milk dairy foods are more than vehicles for fat. Like other foods, they are a complex matrix of vitamins, minerals, proteins and carbohydrates as well as unsaturated fats. Part of the controversy and inconclusiveness about the role of saturated fats in health and disease could be because the other qualities of the food they’re “packaged” in matters.
Interestingly, European-based studies on dairy fat, which tends to be consumed there in the form of quality cheese and yogurt, are more likely to find positive effects on health than American studies, where people eat more full fat dairy combined with sugar and refined carbohydrates, as with ice cream, pizza and fast food.
Just because full-fat dairy may have a neutral or slightly positive effect on cardiometabolic health doesn’t mean you should load up on cheese in the interest of heart health, however. A 2017 study, also in the American Journal of Clinical Nutrition, found that a butter-rich diet increased “bad” LDL cholesterol more than a cheese-rich diet, but that replacing butter and cheese with monounsaturated-rich olive oil or polyunsaturated-rich corn oil, resulted in lower LDL, a finding that’s consistent with other research.
While full-fat dairy may be compatible with health and longevity, there are many foods that may contribute more strongly to those goals, such as vegetables, fruits, pulses (beans and lentils), whole grains, fish and plant-based fats like nuts, seeds, avocados and olive oil.