Full-fat dairy shows benefits without raising body fat or cholesterol, study finds
A Canadian study led by University of Toronto professor Harvey Anderson is offering new evidence in support of full-fat dairy consumption.
The findings, from a 12-week study of 74 adults, demonstrate that three daily servings of full-fat dairy can be incorporated into a person’s diet without negatively affecting their body weight or composition, energy metabolism or blood lipid levels. The results were published recently in The Journal of Nutrition.
Dairy products contain saturated fats, which contributes to high cholesterol and increased risk of cardiovascular disease. For this reason, dietary guidelines in Canada and around the world have traditionally recommended fat-free or low-fat dairy foods to reduce saturated fat intake.
Anderson, who is a professor of nutritional sciences at U of T’s Temerty Faculty of Medicine, says despite these concerns, numerous human studies have found no association between full-fat dairy consumption and negative health outcomes. Some studies — including recent research led by Temerty Medicine professor Kozeta Milliku — have also reported positive, or protective, effects related to dairy intake.
In the current study, 74 adults with overweight or obesity were randomly assigned to one of three diets: low-dairy, calorie-restriction; energy-neutral with three daily servings of dairy; or unrestricted with three daily servings of dairy. The participants were also counseled to follow Canada’s food guide and provided with full-fat dairy products for the study.
After 12 weeks, the researchers did not observe meaningful differences in weight gain, body composition or cholesterol levels between the participants who followed a low-dairy diet and those who consumed three daily servings of dairy. On the other hand, participants who ate more dairy saw improvements in blood pressure and had higher intake of calcium, protein and vitamin D.
“Those that had three servings of dairy didn’t have adverse levels of blood cholesterol or lipids or evidence of insulin resistance,” says Anderson.
According to him and other researchers, the disagreement between the harms expected from saturated fats in dairy and the reported neutral or positive effects from human studies could be explained by the dairy matrix hypothesis, which posits that the physical structure of dairy foods affects how the nutrients within are digested and how they impact the body.
“With dairy products, it’s got two proteins — casein and whey — that are bound together with fat and with nutrients mixed in,” says Anderson.
It’s this unique and complex physical structure that, he says, is responsible for the slow and steady delivery of nutrients from dairy products and that expands their health impacts to more than just the sum of the isolated nutrients.
Anderson notes that the study findings are especially relevant for older people who have lower energy needs overall and may therefore have difficulties getting sufficient protein and nutrients. He says that for many older adults, dairy products are a familiar and energy- and nutrient-dense option to help meet their nutritional needs, without increasing their risk of diabetes and other chronic diseases.
More broadly, the study highlights the importance of approaching nutritional sciences research and dietary guidelines through a whole food lens, instead of focusing on single nutrients.
Faced with constantly changing trends in food and nutrition and sometimes conflicting messaging around diet, Anderson is straightforward: “Keep it simple, eat a variety of foods and not too much of anything.”
This research was supported by Dairy Research Cluster 3 under the Canadian Agricultural Partnership AgriScience Program, and the Mitacs Accelerate program.
