An increase in dairy consumption is associated with a reduced risk of mortality and major cardiovascular disease (CVD) events, such a stroke, according to a study published in The Lancet.1
A team of researchers for the Prospective Urban Rural Epidemiology (PURE) study conducted a large, multinational group analysis to evaluate the association between the consumption of dairy products (total and specific types) with mortality and major CVD.
The main outcome was the combination of mortality or major CV events including death from CV causes, nonfatal myocardial infarction, stroke, or heart failure. Secondary outcomes included total mortality and major CVD.
The investigators invited 153,220 participants, aged 35 to 70 years, from 21 countries to take country-specific validated food frequency questionnaires to record dairy product intake. Dairy products, which included milk, cheese, and yogurt, were further grouped into whole-fat and low-fat dairy.
Of the total, 136,384 (92.3%) of participants with completed questionnaires were included in the study. Participants with a history of CVD at baseline were excluded from participation.
At a median follow-up of 9.1 years, the investigators reported 10.567 (7.7%) participants had either died (n=6796) or had a major CV event (n=5855): noncardiovascular death (n=4796), cardiovascular death (n=2000), myocardial infarction (n=2594), stroke (n=2718), and heart failure (516).
High consumption of total dairy (>2 servings/d), when compared with no intake, was associated with a reduced risk of combined outcome (hazard ratio [HR], 0.84), total mortality (HR, 0.83), noncardiovascular mortality (0.86), cardiovascular mortality (0.77), major CVD (0.78), and stroke (0.66). Myocardial infarction results were not significant (HR, 0.89).
High consumption of milk and yogurt (>1 serving/d), when compared with no intake, was associated with reduced risk of combined outcome (HR, 0.90 and 08.6, respectively). Cheese consumption was not significantly associated with reduced combined outcome (HR, 0.88), and butter consumption was low with no significant clinical associations (HR, 1.09).
“In conclusion, we observed that higher dairy consumption was associated with lower risks of mortality and cardiovascular disease, particularly stroke,” the authors wrote. “Our study suggests that consumption of dairy products should not be discouraged and perhaps should even be encouraged in low-income and middle-income countries where dairy consumption is low.”
In a comment written by Jimmy Chun Yu Louie and Anna M Rangan in The Lancet, certain caveats to the study are addressed. While the investigation involves a large cohort with country-specific validated food surveys, the authors of the comment note the association between reduced CV risk and dairy consumption is significantly due to the consumption of milk and yogurt, not cheese and butter.2
A limitation of the study that the commenters noted was that the participants’ diet assessments were recorded at baseline with a relatively short follow-up period. “Younger participants who had not yet developed major [CVD] or died, could have been misclassified as having low or no risk, although they might progress towards these outcomes in the future,” according to the comment.
The authors of the comment readdress the study conclusion that dairy consumption should not be discouraged but even possibly encouraged, adding that “it is not the ultimate seal of approval for recommending whole-fat dairy over its low-fat or skimmed counterparts.”
“Readers should be cautious and should treat this study only as yet another piece of evidence (albeit a large one) in the literature,” the comment authors concluded.
- Dehghan M, Mente A, Randarajan A, et al; for The Prospective Urban Rural Epidemiology (PURE) study. Association of dairy intake with cardiovascular disease and mortality in 21 countries from five continents (PURE): a prospective cohort study [published online September 11, 2018]. Lancet. doi: 10.1016/s0140-6736(18)31812-9
- Louie JCY, Rangan AM. No need to change dairy food dietary guidelines yet [published online September 11, 2018]. Lancet. doi: 10.1016/ S0140-6736(18)31945-7