Previously published research has suggested that higher dairy intake is associated with a lower risk of diabetes, high blood pressure, and metabolic syndrome. But these studies have tended to focus on North America and Europe.
To see whether these associations might also be found in a broader range of countries, a team of researchers from around the world drew on people taking part in the Prospective Urban Rural Epidemiology (PURE) study.
Participants were all aged between 35 and 70 and came from 21 countries: Argentina; Bangladesh; Brazil; Canada; Chile; China; Colombia; India; Iran; Malaysia; Palestine; Pakistan; Philippines, Poland; South Africa; Saudi Arabia; Sweden; Tanzania; Turkey; United Arab Emirates; and Zimbabwe.
Usual dietary intake over the previous 12 months was assessed by means of Food Frequency Questionnaires. Dairy products included milk, yogurt, yogurt drinks, cheese and dishes prepared with dairy products, and were classified as full or low fat (1-2%).
Butter and cream were assessed separately as these are not commonly eaten in some of the countries studied.
Information on personal medical history, use of prescription medicines, educational attainment, smoking and measurements of weight, height, waist circumference, blood pressure and fasting blood glucose were also collected.
Data on all five components of the metabolic syndrome were available for nearly 113,000 people: blood pressure above 130/85 mm Hg; waist circumference above 80 cm; low levels of (beneficial) high density cholesterol (less than 1-1.3 mmol/l); blood fats (triglycerides) of more than 1.7 mmol/dl; and fasting blood glucose of 5.5 mmol/l or more.
Average daily total dairy consumption was 179g, with full fat accounting for around double the amount of low fat and some 46,667 people had metabolic syndrome (at least three of the five components).
Findings
The results, published in BMJ Open Diabetes Research & Care, show suggest that total dairy and full fat dairy, but not low fat dairy, were associated with a lower prevalence of most components of metabolic syndrome, with the size of the association greatest in those countries with normally low dairy intakes.
At least two servings a day of total dairy was associated with a 24% lower risk of metabolic syndrome, rising to 28% for full fat dairy alone, compared with no daily dairy intake.
The health of nearly 190,000 participants was tracked for an average of nine years, during which time 13,640 people developed high blood pressure and 5351 developed diabetes.
At least two servings a day of total dairy was associated with an 11-12% lower risk of both conditions, rising to a 13-14% lower risk for three daily servings. The associations were stronger for full fat than they were for low fat dairy.
This is an observational study, and as such can't establish cause. Food frequency questionnaires are also subject to recall, and changes in metabolic syndrome weren't measured over time, all of which may have influenced the findings.
Nevertheless, the researchers say: "If our findings are confirmed in sufficiently large and long term trials, then increasing dairy consumption may represent a feasible and low cost approach to reducing metabolic syndrome, hypertension, diabetes, and ultimately cardiovascular disease events worldwide."
Previous research
The American Journal of Clinical Nutrition published a study of overweight adults and their dairy intake in 2019 which found that a high dairy diet (HDD) was linked to lower blood pressure, which the researchers credited to an accompanying increase in calcium.
The research compared the effect of a HDD with a low dairy diet (LDD) in participants who consumed three meals per day over two separate six-week periods. Those on the HDD were instructed to consume five or six portions of dairy per day, while those on the LDD consumed less than one portion.
The Journal of Nutrition published a study in 2011 concluding that a diet high in low-fat dairy products is associated with lower diabetes risk in postmenopausal women, particularly those who are obese.
Karen Margolis et al said the data from a prospective cohort study of 82,076 postmenopausal women enrolled in the ongoing Women’s Health Initiative Observational Study (WHI-OS) showed that high yogurt consumption was associated with a significant decrease in diabetes risk, but that there was no relationship between high-fat dairy product consumption and diabetes risk.
Source: BMJ Open Diabetes Research & Care
Yusuf. S., et al
"Association of dairy consumption with metabolic syndrome, hypertension and diabetes in 147,812 individuals from 21 countries"