All those years of reaching for the "skim" and "fat-free" options in the milk and cheese aisle may not have been the heart-healthy move we once thought, according to a new study.
Published earlier this year in the Journal of Nutrition,a Canadian study re-examines what we long thought we knew about dairy's effect on cholesterol and cardiovascular health.
Researchers randomly assigned 74 overweight or obese people to one of three diets, all of which contained full-fat dairy products. One was both low-calorie and low-dairy; one was "energy neutral" (eating exactly as many calories as you need to function without losing or gaining weight) with three daily servings of dairy; and one was unrestricted with three daily servings of dairy.
After following
the diet for 12 weeks, participants did not experience a difference in weight gain or body composition, regardless of how much dairy they consumed. Researchers also did not notice a difference in cholesterol levels between the groups.
What they did find contradicted years of conventional wisdom about full-fat dairy's impact on the body: The groups that consumed more dairy saw improvements in blood pressure and had higher intake of calcium, protein and vitamin D.
"Those who had three servings of dairy didn’t have adverse levels of blood cholesterol or lipids or evidence of insulin resistance,” Dr. Harvey Anderson, lead author and professor of nutritional sciences at the University of Toronto's Temerty Faculty of Medicine, said in a news release.
While limiting high-fat foods is still generally applicable dietary advice, scientists believe the "dairy matrix hypothesis" could account for some of the discrepancy between how saturated fats typically break down in the human body versus in dairy.
The theory hinges on the physical structure of a food and how its nutrients are digested. The unique physical structure of dairy means it breaks down more slowly over time, releasing nutrients at a steady pace and expanding potential health benefits. This could be especially welcome news for older adults who may struggle to get enough nutrients, Anderson said.
"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," according to the news release.
New study aligns with recently updated food pyramid
The findings are good news for those hoping to stick to the new food pyramid released by the U.S. Department of Agriculture under Health Secretary Robert F. Kennedy Jr. on Jan. 7, which emphasized full-fat dairy, protein and "healthy fats."
The new guidelines emphasize food items historically recommended in moderation, specifically red meat, whole-fat dairy and several types of fats, including trans fats. These categories align with the messaging RFK Jr. has favored as part of the "Make America Healthy Again" movement.
Previous nutrition guidelines suggested minimizing or avoiding full-fat dairy and all types of fat, including healthy and saturated fats. The new guidance recommends three servings of full-fat dairy per day but caps saturated fat at 10% of daily calories.
Is whole dairy better for you?
This study is one of many to question the link between saturated fats, whole-fat dairy and health issues, including cardiovascular health and good versus bad cholesterol.
The number of participants in the latest study was relatively small, and researchers didn't conduct the study over a long period; however, recent research has shown that full-fat milk, cheese and yogurt "may not have the negative effects on heart or vascular health as previously thought," according to the Mayo Clinic. In fact, some studies have even found potentially positive effects associated with whole dairy consumption.
The biggest potential pitfall of too much full-fat dairy is its high fat content, according to experts. Only 10% of your daily calories should come from saturated fats, a percentage that is easy to meet or surpass through dairy consumption alone.
Harvard's T.H. Chan School of Public Health laid out an example of how quickly the push for three servings of full-fat milk a day can surpass the dietary rule: In a standard 2,000-calorie-a-day diet, 10% of your calories equals about 22 grams of saturated fat. One serving of whole milk, one serving of whole-fat Greek yogurt and one serving of whole-fat cheese a day would already add up to 17 grams of saturated fat, before any other food groups were added.
But fat is not always a bad thing. Our bodies need several types of fats to function, and whole dairy is a good source of "healthy" fats, which help us absorb fat-soluble vitamins like vitamin A and K, according to the University of Washington.
Whole dairy contains more nutrients (including protein, calcium, phosphorus, and vitamins A, B and D), more essential omega-3 fatty acids and helps you feel full for longer. Reduced-fat dairy options, on the other hand, offer many of the same nutrients while contributing less saturated fat to your diet.
Additionally, as the University of Toronto study points out, saturated fat from dairy may not break down in the body the same way as fat from other food sources.
Choosing whole versus low-fat depends on individual daily needs. Those looking to reduce or avoid additional saturated fat in their diets may opt for reduced-fat options, whereas someone who needs more of the other nutrients offered by whole dairy may opt for full-fat. As with all things in your diet, it's about the bigger picture.
"Keep it simple, eat a variety of foods and not too much of anything," Anderson said.
This article originally appeared on USA TODAY: Low-fat dairy may not be as beneficial after all, new study finds
