Rates of type 2 diabetes and hypertension, or high blood pressure, are rising in the United States.
As it stands, experts estimate that about 34 million people in the U.S. have diabetes, and almost half of the adult population have hypertension. Rates are also increasing elsewhere in the world, particularly elsewhere in the West.
Consequently, healthcare professionals are invested in understanding how to prevent these diseases. Because an unhealthful diet is a significant risk factor for both issues, adjusting the diet seems to be a promising approach.
Dairy products are of particular interest, following research indicating that dairy consumption is associated with lower blood pressure. Studies have also shown that eating more dairy is linked with a lower risk of diabetes.
However, most of this research has only included participants in Europe and North America, which has limited the generalizability of the findings.
Now, a large international study of data from almost 150,000 people has concluded that a higher intake of dairy, especially whole fat varieties, is associated with a lower risk of diabetes and high blood pressure.
The study also concluded that increased whole fat dairy consumption was associated with lower rates of metabolic syndrome — a cluster of symptoms that increase the risk of heart disease.
The findings are published in the journal BMJ Open Diabetes Research & Care.
The investigation included data from 147,812 people from 21 countries, spanning Asia, North and South America, Africa, and Europe. The participants ranged in age from 35 to 70.
The researchers learned about the participants’ food intake over a year using questionnaires. On these, participants recorded the number of times that they had consumed specific items from a list, with an average follow-up of 9 years.
Among the dairy products on the list were milk, yogurt, cheese, and dishes prepared with dairy.
The researchers did not incorporate butter and cream intake data into the overall analysis, as these were not common in many of the participants’ areas. However, the team did assess associations between the intake and health outcomes separately.
Dairy products were classified either as whole fat, such as whole milk, or low fat, such as skim milk.
The researchers also considered information about each participant’s medical history, prescriptions, education, blood pressure, waist circumference, and levels of glucose and fat in the blood.
The latter measurements are important in determining whether a person has metabolic syndrome or type 2 diabetes.
The results of the study showed that, on average, people ate 179 grams of dairy each day. This is slightly less than a glass of milk or a cup of yogurt per day, each of which measures 244 grams.
People in Europe and North and South America, on average, ate more dairy than those in Asia and Africa. People in Europe and North America also tended to eat more low fat dairy products, whereas those in other regions consumed more whole fat varieties.
When analyzing the associations, the researchers found that having at least 2 servings of dairy per day was associated with a 24% lower risk of metabolic syndrome, compared with having no dairy at all.
Having at least 2 servings of whole fat dairy, meanwhile, was associated with a 28% lower risk of metabolic syndrome. Consuming only low-fat dairy was not associated with a reduction in metabolic syndrome risk.
While butter intake was also associated with a lower risk of metabolic syndrome, consumption was very low, on average 3 grams per day, and the available data were limited.
Having at least 2 servings per day of any dairy product was also associated with an 11–12% lower risk of having both diabetes and high blood pressure. The association was stronger in those who consumed whole fat dairy.
Summarizing the findings, study co-author Andrew Mente, Ph.D., a principal investigator at the Population Health Research Institute, in Hamilton, Ontario, said:
“Higher intake of dairy foods, such as milk, yogurt, and cheese, especially whole fat dairy rather than low fat dairy, is associated with a lower prevalence of metabolic syndrome and with a lower risk of developing hypertension and diabetes.”
The findings may seem counterintuitive, as many people tend to think of whole fat products as less healthful than reduced fat alternatives. The authors hope to dispel this myth.
“Dairy foods and dairy fat provide high-quality protein and a wide range of essential vitamins and minerals, including calcium, magnesium, potassium, zinc, phosphorus, and vitamins A, B-12, and riboflavin,” Mente explains.
Although it is not yet clear how dairy might protect against the health issues in question, the researchers hope to confirm their findings in large, long-term trials.
If their conclusions are confirmed, the researchers say, increasing the consumption of dairy could prove to be a “feasible and low-cost approach” to reducing rates of metabolic syndrome, high blood pressure, and diabetes worldwide.