— Even the saturated fat from it appears acquitted in observational data
Eating dairy daily -- including full-fat products -- was associated with lower risk of death or cardiovascular disease in the large multinational PURE cohort study.
Consumption of more than two servings of dairy versus no intake each day was linked with a lower risk of death or a major cardiovascular event, including death from cardiovascular causes, non-fatal MI, stroke, and heart failure (HR 0.84, 95% CI 0.75-0.94,P=0.0004).
The findings were the same for both whole-fat and low-fat dairy, reported Mahshid Dehghan, PhD, of McMaster University in Hamilton, Ontario, and colleagues in The Lancet
People whose only dairy intake was whole-fat products still had significantly lower risk with higher intake of both the composite endpoint (HR 0.71 for more than two versus less than half a serving a day, 95% CI 0.60-0.83) and total mortality and major cardiovascular disease separately (HRs 0.75 and 0.68). The findings were similar but not significant for people who ate both full-fat and low-fat dairy.
Notably, consuming more saturated fat from dairy did not significantly impact the composite outcome, total mortality, or major cardiovascular disease.
Among individual foods, the composite endpoint was lower with more than one serving per day of milk (HR 0.90, 95% CI 0.82-0.99, P=0.0529) or yogurt (0.86, 0.75-0.99, P=0.0051) but not significantly so with cheese (0.88, 0.76-1.02, P=0.1399) or butter (1.09, 95% CI 0.90-1.33, P=0.4113).
Guidelines have typically recommended low-fat or no-fat dairy intake, "predominantly based on the presumed harms of a single macronutrient category (saturated fatty acids) on a single cardiovascular risk marker (LDL cholesterol), and concerns about higher calories in higher fat foods," the researchers noted.
"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," they concluded.
But, Jimmy Chun Yu Louie, MNutrDiet, PhD, of the University of Hong Kong, and Anna Rangan, PhD, of the University of Sydney, an accompanying commentary cautioned against changing guidelines just yet in an accompanying commentary.
"It is not the ultimate seal of approval for recommending whole-fat dairy over its low-fat or skimmed counterparts," they wrote. "Readers should be cautious and should treat this study only as yet another piece of evidence (albeit a large one) in the literature."
"Currently with the evidence that we have reviewed, we still believe that you should try to limit your saturated fat including fat that this is coming from dairy products," commented Jo Ann Carson, PhD, of UT Southwestern Medical Center in Dallas and a spokesperson for the American Heart Association.
"It is probably wise and beneficial to be sure you're including dairy in that overall heart-healthy dietary pattern, but we would continue to recommend that you make lower fat selections in the dairy products," Carson told MedPage Today regarding the study, with which she was not involved.
This "offshoot -- an analysis of data dealing with a question that was not the original hypothesis of the PURE study" may be no different, suggested Marion Nestle, MPH, PhD, of New York University in New York City, in an interview with MedPage Today.
"A previous publication found that fat in general was associated with a reduced CHD [coronary heart disease] and stroke risk. These studies seem aimed to prove that fat is benign," Nestle explained.
The researchers evaluated over 136,000 individuals (ages 35-70) across 21 countries. The participants completed frequency questionnaires on their consumption of dairy products like milk, yogurt, and cheese.
Comparing three or more dairy servings daily against no regular dairy intake, the researchers found the following outcomes:
- Total mortality: HR 0.83 (P=0.0052)
- Noncardiovascular mortality: HR 0.86 (P=0.046)
- Cardiovascular mortality: HR 0.77 (P=0.029)
- Major cardiovascular disease: HR 0.78 (P=0.0001)
- Stroke: HR 0.66 (P=0.003)
There were no noteworthy connections between myocardial infarction and dairy intake (HR 0.89, 95% CI 0.71-1.11; P=0.163).
The researchers acknowledge the limitations of their work. "Our study is an observational study and we report association between exposure and outcome we cannot prove any causality," emphasized Dehghan.
On the other hand, she called the findings "robust and more widely applicable" due to the large number of events across a broad range of dairy consumption in a variety of different settings and cultures with varying dietary patterns.
"Also, adjustments for confounders, for consumption of other food groups, and analyses to exclude reverse causality (by excluding those with prior CVD or those who died or had an event in the first 2 years) did not alter our results. However, ideally our findings require confirmation in randomized trials evaluating the effects of increasing dairy consumption on BP, glucose, and clinical outcomes," Dehghan added.
While industry funding has been considered a possible factor in dairy study findings, Nestle also pointed out that PURE was funded by a number of pharmaceutical companies and a sugar association without any dairy funders. Dehghan confirmed that the research did not receive funding from the food industry.
Looking ahead, Dehghan said new findings from PURE are in development, assessing the association between dairy and diabetes and some cardiometabolic risk factors.
The study is funded by the Heart and Stroke Foundation of Ontario, Population Health Research Institute, the Canadian Institutes of Health Research (CIHR), Heart and Stroke Foundation of Ontario, support from CIHR's Strategy for Patient Oriented Research (SPOR) through the Ontario SPOR Support Unit, as well as the Ontario Ministry of Health and Long-Term Care, AstraZeneca (Canada), Sanofi-Aventis (France and Canada), Boehringer Ingelheim (Germany and Canada), Servier, and GlaxoSmithKline, Novartis and King Pharma (Argentina), and a variety of organizations supporting individual country's contributions, including The SA Sugar Association (South Africa), and Astra Zeneca (Turkey).
Carson and Dehghan disclosed no relevant conflicts of interest.
Nestle disclosed she is author of books on food politics and paid to teach and lecture on such topics.
Read the original article on Medpage Today: Whole-Fat Dairy Associated with Heart Benefit in PURE Study