Full-Fat Dairy May Not Harm Heart Health, Canadian Study Finds

For decades, health experts have encouraged people to choose low-fat or fat-free milk, yogurt and other dairy products to reduce saturated fat intake and protect cardiovascular health. However, emerging research is challenging the assumption that full-fat dairy is necessarily harmful, with a new Canadian study finding no significant adverse effects on cholesterol, body weight or metabolism among adults who consumed it daily.

The study, led by Harvey Anderson, a professor of nutritional sciences at the University of Toronto’s Temerty Faculty of Medicine, found that consuming three servings of full-fat dairy every day for 12 weeks did not lead to unfavourable changes in body weight, body composition, energy metabolism or blood cholesterol levels. Participants who consumed more dairy also recorded improvements in blood pressure and had higher intakes of several essential nutrients.

Published in The Journal of Nutrition, the findings add to growing scientific evidence suggesting that the relationship between dairy fat and cardiovascular health may be more complex than previously understood.

Why Have Health Experts Recommended Low-Fat Dairy?

Dietary guidelines in Canada and several other countries have traditionally favoured low-fat and fat-free dairy products because of concerns surrounding saturated fat. Full-fat milk and other dairy products contain higher amounts of this type of fat, which can increase low-density lipoprotein (LDL) cholesterol in the bloodstream.

Commonly known as bad cholesterol, LDL can contribute to the accumulation of fatty deposits inside arteries. This process, known as atherosclerosis, can restrict blood flow and increase the risk of heart attacks, strokes and other cardiovascular complications.

As a result, limiting saturated fat consumption has long been a central part of conventional dietary advice, with reduced-fat dairy often recommended as an alternative.

However, findings from human studies have increasingly questioned whether consuming full-fat dairy automatically translates into poorer health outcomes.

Anderson has pointed out that several studies involving human participants have failed to establish a consistent link between full-fat dairy consumption and negative health effects. Some research has also suggested potential benefits associated with these products.

For instance, a separate study led by Kozeta Milliku, a professor at Temerty Medicine, identified an association between whole-fat milk consumption and a lower risk of childhood obesity.

Such findings have encouraged researchers to examine dairy foods as a whole rather than evaluating their health effects solely on the basis of individual nutrients such as saturated fat.

What Did the 12-Week Full-Fat Dairy Study Find?

To investigate the effects of regular dairy consumption, Anderson and his research team conducted a 12-week trial involving 74 adults with overweight or obesity.

Participants were randomly divided into three groups, each following a different dietary approach.

The first group followed a calorie-restricted diet with minimal dairy consumption. The second group incorporated three servings of dairy into their daily diet while maintaining an energy-neutral calorie intake, meaning participants aimed to consume approximately as many calories as their bodies burned.

The third group also consumed three daily servings of dairy but had no specific restrictions on their overall calorie intake.

All three groups received dietary guidance based on Canada’s food guide. Researchers also provided the full-fat dairy products consumed during the study.

After 12 weeks, the researchers assessed participants for changes in body weight, body composition and several indicators of metabolic health, including blood cholesterol levels.

The results did not support the expectation that eating more full-fat dairy would necessarily produce unfavourable metabolic changes.

Participants consuming three servings of dairy daily showed no meaningful differences in body weight, body composition or blood cholesterol compared with those following a low-dairy diet.

The researchers also found improvements in blood pressure among participants in the higher-dairy groups. Their diets provided greater amounts of calcium, protein and vitamin D, all of which contribute to important bodily functions.

Calcium and vitamin D are particularly important for maintaining bone health, while protein supports muscle development and repair. These nutrients also contribute to several other processes necessary for normal bodily functioning.

“Those that had three servings of dairy didn’t have adverse levels of blood cholesterol or lipids or evidence of insulin resistance,” says Anderson.

Blood lipids refer to fats and fat-like substances circulating through the bloodstream, including cholesterol and triglycerides. Insulin resistance, meanwhile, develops when the body’s cells become less responsive to insulin, making blood sugar regulation more difficult. Over time, it can increase the risk of developing type 2 diabetes.

Does Full-Fat Dairy Increase the Risk of Heart Disease?

The Canadian study adds to research suggesting that the health effects of dairy consumption cannot be determined by saturated fat content alone.

Although saturated fat can raise LDL cholesterol, the findings indicate that consuming full-fat dairy as part of a daily diet does not necessarily result in higher blood cholesterol or other unfavourable metabolic changes over the short term.

However, the researchers cautioned against interpreting the results as definitive evidence that full-fat dairy protects against cardiovascular disease.

The trial involved only 74 participants and lasted 12 weeks. Its relatively small sample size and short duration mean that it cannot establish whether the observed effects would continue over several years or translate into a reduced risk of heart attacks, strokes and other cardiovascular conditions.

Larger studies involving more participants and longer follow-up periods will be necessary to understand the long-term effects of full-fat dairy consumption.