Research is starting to emerge that shows the generalized association between dietary saturated fat and blood cholesterol doesn’t hold true for all foods high in saturated fats. There are many different fats that fall into the category of saturated fat, and they may not all have the same effect. A well-known study by de Oliveira Otto showed that a higher intake of dairy saturated fat was associated with a lower incidence of cardiovascular disease risk while a higher intake of saturated fat from meat was associated with a higher risk of cardiovascular disease.1 In fact, the Heart & Stroke Foundation of Canada points out “there is emerging evidence to suggest that the health effects of saturated fats could vary depending on the food sources in which they are found.” They go on to conclude that it is probably more important to focus on the overall quality of diet without giving limits to saturated fat. In the words of their press release announcing their new position on saturated fat, they urged Canadians to “cut the crap” and to “focus on a healthy diet of natural/whole foods.”
Scientists continue to explore the complex relationship between dietary fats and cardiovascular risk. In 2016, researchers in Denmark completed a trial comparing the effect of regular-fat cheese vs reduced-fat cheese vs a no-cheese diet in a group of 139 people (94 women, 47 men).2 Subjects were randomly assigned to the different groups.
The groups that were assigned to eat cheese ate about 80 g of cheese/day, adjusted up or down depending on the calorie needs of each participant. The group that didn’t eat cheese made up the difference in calories with white bread and jam. Total cholesterol, LDL cholesterol (the so-called “bad” cholesterol) and HDL cholesterol (the “good” cholesterol), along with several other risk markers of metabolic syndrome, were measured at the beginning and end of the 12-week study.
There was no significant difference in the LDL levels in the different groups. Similarly, other risk markers of metabolic risk such as blood pressure and fasting glucose levels didn’t change either, whether people were in the regular-fat cheese, reduced-fat cheese or bread and jam group. The HDL cholesterol was slightly higher in the group that ate the regular cheese compared to the group that ate the bread and jam, though this improvement was not statistically significant.
The study was published in the American Journal of Clinical Nutrition. The lead author of this study, Farinaz Raziani told a NY Times reporter, “It is reasonable to include regular-fat cheese as part of a healthy diet.”
Dariush Mozaffarian, researcher and physician, concurs. In an expert analysis paper he wrote for the American College of Cardiology in May 2016, he champions “food based dietary patterns for improving cardiometabolic health rather than outdated emphases on total fat, saturated fat or calorie counting.” In his table of evidence-based dietary priorities for cardiovascular and metabolic health, he lists dairy products, especially yogurt and cheese, in the “Consume More” category. He says the target should be 2-3 servings/day. He notes that “the choice of whole-fat vs low-fat can be based on personal preference as current evidence is insufficient to confirm which is superior.”
Very recently, a prospective study looking at a population of adults over the course of 22 years, found no association between consumption of dairy foods and death from any cause or the incidence of cardiovascular disease.The NIH funded study determined whether subjects consumed dairy products by measuring blood levels of particular fatty acids that are markers for dairy, as opposed to asking subjects what they ate. This provides an objective measure of exposure to dairy foods. In fact, the researchers found that the higher the level of heptadecanoic acid, one of the markers of dairy consumption, the lower the rate of death due to cardiovascular disease or stroke. As the lead researcher stated in the press release announcing the publication,
“Consistent with previous findings, our results highlight the need to revisit current dietary guidance on whole fat dairy foods, which are rich sources of nutrients such as calcium and potassium. These are essential for health not only during childhood but throughout life, particularly also in later years when undernourishment and conditions like osteoporosis are more common.”
Most recently, findings from the PURE study (Prospective Urban Rural Epidemiology) add to this growing body of evidence. Researchers followed subjects from 21 countries, including Canada, for nine years. They found that those with higher whole fat dairy intake (>2 servings) had a 32% lower risk of major cardiovascular diseases, even lower than the reduced risk associated with consuming a combination of whole fat and reduced fat dairy.4Whole fat dairy included whole fat milk, whole fat yogurt and whole fat cheese.
The fact that Raziani’s group didn’t notice a difference in the effect of regular-fat cheese vs reduced-fat cheese on cardiometabolic risk factors may have to do with other components in cheese. For example, both regular-fat cheese and reduced-fat cheese are fermented foods, and fermentation alters the food matrix in ways that may be cardioprotective.
de Oliveira Otto’s group notes that the bioactive phospholipids and proteins that enclose the milk fat may account for the different effect of dairy saturated fat on blood lipids.3 They further note that nutrients in dairy foods such as calcium, vitamin D, phosphorus and potassium could lower stroke risk.
Mozaffarian, in his comprehensive review of Dietary and Policy Priorities for Cardiovascular Disease and Obesity, states, “In sum, dairy products represent a diverse class of foods, with complex effects that vary by specific product type and with emerging mechanistic pathways that appear to include influences of fermentation and probiotics. No long-term studies support harms, and emerging evidence suggests some potential benefits, of dairy fat or high-fat dairy foods such as cheese.”