For years, Americans have been told to avoid high-fat dairy products; Decades of dietary advice has held that cutting fat was key to a heart-healthy diet, spurring a whole industry of low-fat dairy products. But a new generation of nutrition research is challenging some of those long-held beliefs—suggesting that the impact of dietary fat is different when it is found in dairy products compared with other foods.
A new study from the University of Minnesota School of Public Health (SPH) adds to this shift. Using data from more than 3,100 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study, researchers tracked dairy consumption and measured coronary artery calcification (CAC)—a buildup of calcium in the arteries that can be an early sign of heart disease. This is believed to be the first prospective study on the associations of whole-fat, low-fat, and total dairy consumption with risk of CAC.
Study participants were first surveyed in the mid-1980s, when they were between the ages of 18 and 30, and then tracked over the following 25 years. Using advanced statistical modeling, researchers looked at how different types of dairy—whole-fat, low-fat, and total dairy intake—related to the presence of CAC later in life. The results, published in The Journal of Nutrition, found:
- Whole-fat dairy appeared protective against CAC. Participants who consumed the most whole-fat dairy had a 24% lower risk of developing CAC compared with those who consumed the least.
- Low-fat and total dairy showed no clear relationship with risk of CAC. Intakes of low-fat and total dairy products were not significantly linked to the presence of this heart disease marker.
- Body weight may play a role. The protective effect of whole-fat dairy weakened slightly after researchers adjusted for participants’ body mass index (BMI), suggesting that the slightly lower average BMI of those who consume dairy may partly explain the association.
“People who regularly consumed whole-fat dairy in young adulthood actually had lower signs of early heart disease decades later, which is further evidence challenging dietary advice that promotes swapping whole-fat dairy for low-fat dairy,” said Ethan Cannon, SPH researcher and lead author. “While nutritionists have long been concerned about the saturated fat found in whole-fat dairy, our research serves as a reminder that the overall effects of a food are not equivalent to those of the individual nutrients it contains. In the case of whole-fat dairy, the drawback of higher blood cholesterol caused by saturated fat may be outweighed by the benefits of the unique blend of nutrients and other constituents also found in dairy.”
The paper calls for additional research to further investigate the impacts of whole-fat dairy on heart health, and to better understand its biological mechanisms, such as the role of specific fatty acids or bioactive compounds in dairy fat.
