Dairy doesn’t affect mortality risk

While dairy products are one of the nine principles of the Mediterranean Diet, there's still some debate over whether they are really good for you. Some research has suggested that consuming dairy in the form of milk or cheese may actually increase your risk of coronary heart disease (CHD) or cardiovascular disease (CVD).

In an effort to clear up any misperceptions, a team of researchers conducted a search of the literature for all prospective studies that assessed dairy intake and reported on any deaths from CHD or CVD. They identified twenty-nine studies from around the world that included a total of over 780,000 adult men and women, with the studies lasting at least 5 and up to 25 years, with an average duration of 13 years (Eur J Epidemiol 2017;32(4):269-287).

The authors analyzed the type of dairy included in each study and standardized the portion sizes into grams per day: 244 grams each for milk and yogurt and 40 grams per cheese. A single serving of total dairy, high-fat dairy, or low-fat dairy, regardless of the dairy's form, was standardized to 200 grams.

After considering such factors as age, sex, smoking status, caloric intake, Body Mass Index, level of exercise, and alcohol intake, the authors could compare those who were diagnosed with CHD or CVD or died of any cause (all-cause mortality) with those who did not.

Somewhat remarkably, they found nearly nothing: total dairy intake was not associated with CHD, CVD, or all-cause mortality. This held true whether they considered high-fat dairy or low-fat dairy alone. Similarly, drinking milk appeared to have no effect on CHD, CVD, or mortality. The only form of dairy that seemed to have some effect on heart disease or all-cause mortality was fermented dairy (including both cheese and yogurt), which appeared to reduce risk by a modest 2% for every 20 grams consumed per day. That said, when considered separately neither cheese nor yogurt appeared to affect risk.

What this means for you

The authors note two issues that might have bearing on the outcomes of this study: first, this study does not look at overall dietary patterns. Those who drank more milk, for example, might have chosen more milk and less sugar-sweetened beverages, with the effects being due to avoiding the sugar-sweetened beverages as opposed to choosing milk.

Second, the possible negative effects of saturated animal fats might be mitigated by the vitamins and minerals that dairy products also contain, making it important to consider the health effects of a food as a whole as opposed to condemning a food based on a single nutrient.

First posted: May 24, 2017