New research from the University of Toronto is challenging long-standing assumptions about full-fat dairy, finding that three daily servings did not lead to meaningful increases in weight, body fat, cholesterol or insulin resistance among adults with overweight or obesity.
The 12-week study, led by Harvey Anderson, a professor of nutritional sciences at the University of Toronto’s Temerty Faculty of Medicine, involved 74 adults who were randomly assigned to different dietary approaches. The findings were recently published in The Journal of Nutrition.
Participants who consumed three servings of dairy daily also experienced improvements in blood pressure and increased their intake of calcium, protein, and vitamin D.
Study Examined Three Servings of Dairy Daily
Researchers divided participants into three groups: one followed a low-dairy, calorie-restricted diet; another followed an energy-neutral diet that included three servings of dairy each day; and a third consumed an unrestricted diet that also included three daily servings.
Those assigned to the dairy groups were provided with full-fat dairy products and received guidance based on Canada’s Food Guide.
After 12 weeks, researchers found no meaningful differences in weight gain, body composition or blood lipid levels between participants consuming three servings of dairy and those following the low-dairy diet.
“Those that had three servings of dairy didn’t have adverse levels of blood cholesterol or lipids or evidence of insulin resistance,” Anderson said.
The dairy-consuming participants also had improved blood pressure and higher intakes of calcium, protein and vitamin D.
Why Full-Fat Dairy Has Been Controversial
Full-fat dairy has traditionally drawn scrutiny because it contains saturated fat. Dietary recommendations in Canada and elsewhere have frequently encouraged consumers to select low-fat or fat-free dairy products to reduce saturated fat intake.
Anderson said, however, that findings from human research have not always supported the assumption that full-fat dairy necessarily produces harmful health effects.
Other research has similarly reported neutral or potentially beneficial associations between dairy consumption and certain health outcomes.
The new study does not establish that full-fat dairy is universally healthier than low-fat dairy, but it adds to research suggesting that the health effects of whole foods may be more complicated than examining a single nutrient.
The Dairy Matrix May Matter
Researchers point to what is known as the “dairy matrix hypothesis” as one possible explanation for why dairy’s effects may differ from what would be expected based solely on its saturated-fat content.
The hypothesis suggests that the physical structure of a food can influence how its nutrients are digested and absorbed and, ultimately, how those nutrients affect the body.
“With dairy products, it’s got two proteins — casein and whey — that are bound together with fat and with nutrients mixed in,” Anderson said, MiNDFOOD reported.
Casein accounts for about 80% of the protein in cow’s milk and is digested relatively slowly, while whey makes up about 20% and provides a faster supply of amino acids. Together, the proteins provide all nine essential amino acids.
That combination of protein, fat and other nutrients may help explain why the effects of consuming dairy as a whole food can differ from the effects predicted by examining saturated fat alone.
Findings May Be Relevant to Older Adults
Anderson said the findings may be particularly relevant to older adults, who generally require fewer calories but still need adequate amounts of protein and other nutrients.
Dairy can provide protein, calcium, vitamin D and energy in a familiar food source. Anderson said it may therefore offer one practical way for older adults to meet nutritional needs without necessarily increasing their risk of chronic disease.
The researchers said the study also highlights the importance of evaluating foods as a whole rather than focusing exclusively on individual nutrients.
Study Has Limitations
The study involved just 74 participants and lasted 12 weeks, meaning the results should not be interpreted as proof that full-fat dairy prevents disease or is healthier for everyone.
Longer and larger studies would be needed to determine whether the findings persist over time and whether they apply to broader populations.
The results instead add to an ongoing debate over how dietary recommendations should account for the complex interactions among nutrients within whole foods.
As dietary advice continues to evolve, Anderson offered a straightforward approach: “Keep it simple, eat a variety of foods and not too much of anything.”
Provided by Dallas Express
