Consuming high-fat dairy tied to less metabolic syndrome, diabetes, hypertension
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Higher intake of whole-fat — but not low-fat — dairy is associated with a lower prevalence of metabolic syndrome, as well as lower incidence of hypertension and diabetes, researchers reported.
“Higher intake of dairy foods, such as milk, yogurt and cheese, especially from whole-fat dairy rather than low-fat dairy, is associated with a lower prevalence of metabolic syndrome and with a lower risk for developing hypertension and diabetes,” Andrew Mente, PhD, associate professor, Population Health Research Institute, McMaster University, Ontario, told Healio. “Consumption of two to three servings of dairy, especially from whole-fat dairy foods, may represent a feasible and low-cost approach to reducing hypertension, diabetes, and ultimately cardiovascular disease events worldwide.”
Global analysis
In a cross-sectional study published in BMJ Open Diabetes Research & Care, Mente and colleagues analyzed data from 112,922 participants in the PURE study, a prospective, epidemiological study of adults aged 35 to 70 years from 21 countries on five continents, with a median follow-up of 9.1 years. Participants completed country-specific validated food frequency questionnaires. Total dairy was defined as milk, yogurt, yogurt drink, cheese, and mixed dishes prepared with dairy; mixed dishes prepared with dairy were disaggregated into their constituents and a proportional weight was assigned to each component. Researchers grouped foods as whole-fat dairy and low-fat dairy. Follow-up occurred at least once every 3 years by telephone or in-person visits by local research teams; participants were asked if they had been diagnosed with hypertension of diabetes.
Researchers assessed the association of dairy intake with prevalent metabolic syndrome, defined as having at least three of five components: systolic BP of at least 130 mm Hg or diastolic BP of at least 85 mm Hg; waist circumference greater than 80 cm for women and at least 94 cm for men (except among Asians or South Americans); HDL cholesterol of 40 mg/dL or lower for men and 50 mg/dL or lower for women; triglyceride level of at least 150 mg/dL; and a fasting blood glucose of at least 100 mg/dL or use of diabetes drugs.
Within the cohort, mean total dairy intake was 179 g per day, with whole-fat dairy consumption almost twice as high as low-fat dairy consumption (mean, 124.6 g per day vs. 65 g per day). Researchers observed the highest intakes of total dairy in Europe, North America, the Middle East and South America; lowest intakes were observed in South Asia, China, Africa and Southeast Asia.
Dairy findings
Researchers found that, compared with no dairy consumption, consuming at least two servings per day of total dairy was associated with a 24% reduced risk for developing metabolic syndrome (OR = 0.76; 95% CI, 0.71-0.8). In analyses stratified by type of dairy consumption, higher intake of whole-fat dairy consumed alone was associated with lower metabolic syndrome prevalence (OR = 0.72; 95% CI, 0.66-0.78), with increased risk observed when high-fat dairy was consumed jointly with low-fat dairy (OR = 0.89; 95% CI, 0.8-0.98).
Low-fat dairy consumed alone was not associated with metabolic syndrome prevalence, according to researchers.
In prospective analyses, researchers examined the association of dairy with incident hypertension among 57,547 participants without hypertension at baseline and incident diabetes among 131,481 participants without diabetes at baseline. During follow-up, 23.7% of participants developed incident hypertension and 4.1% of participants developed incident diabetes. Researchers found that consumption of at least two servings of total dairy per day was associated with a lower incidence of hypertension (HR = 0.89; 95% CI, 0.82-0.97) and lower incidence of diabetes (HR = 0.88; 95% CI, 0.76-1.02) compared with participants who reported consuming no dairy.
“A next step would be to study dairy, especially whole fat dairy and possibly fermented dairy like yogurt and cheese, in a randomized controlled trial to assess their impact on blood glucose and future risk of diabetes,” Mente said. “This would help to better assess whether the protective associations of dairy with health, as seen on observational studies, are causal.” – by Regina Schaffer
For more information:
Andrew Mente, PhD, can be reached at the Population Health Research Institute, 237 Barton Street East, Hamilton, ON L8L 2X2
Canada; email: andrew.mente@phri.ca.
Perspective
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Joanna Mitri, MD, MS
The authors assessed the association of dairy intake with prevalence of metabolic syndrome cross-sectionally and with incident hypertension and incident diabetes prospectively in a large, multinational cohort study.
In the cross-sectional part of the study, higher intake of total dairy, defined as at least two servings per day, was compared with zero dairy intake. Higher intake of whole-fat dairy was associated with lower prevalence of metabolic syndrome. It is very important to note that reverse causation cannot be properly ruled out in cross-sectional designs.
Similarly, in a prospective analysis, higher intake of total dairy was associated with 11% lower incidence of hypertension and 12% lower incidence of diabetes compared with zero dairy intake. This is consistent with previous literature suggesting a 2% to 15% decreased risk for type 2 diabetes with dairy intake of at least three servings per day (Mitri J, et al. Diabetes Metab Syndr. 2019; doi:10.1016/j.dsx.2019.07.064.). Due to the observational nature of the study, we should refrain from making strong statements about optimal fat content in dairy or optimal servings of dairy per day. In addition, most observational nutrition studies rely on food frequency questionnaires that are subject to participants' recall, which may certainly influence the findings.
There is a need to have prospective clinical trials evaluate the effect of dairy products on diabetes-related outcomes and how changes in diet overall could affect lipids, beta-cell function and insulin sensitivity.
There is also need for randomized clinical studies that differentiate the impact of low- vs. high-fat dairy intake on metabolic syndrome progression and type 2 diabetes development. However, the design and execution of such studies are difficult. Short-term clinical trials might help shed light on the short-term effects of such intervention. Meanwhile, it seems reasonable for those at risk for diabetes who eat dairy to judiciously include high-fat dairy as part of a healthy diet and within the allowed energy intake, rather than consuming a low-fat meal with added sugars.
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