People who consume dairy products have lower rates of cardiovascular disease than those who avoid them, according to a global study that runs counter to received wisdom about healthy diet.
Published in The Lancet, researchers examined food intake by more than 130,000 people around the world in the most extensive inquiry of its kind. They concluded that eating about three servings of dairy products a day was associated with lower rates of cardiovascular disease and death, compared with lower levels of consumption.
In addition, the study found that people who consumed three servings of whole fat dairy per day had lower rates of mortality and cardiovascular disease than those who consumed less than half a serving.
The researchers considered one standard serving of dairy to be equivalent to a glass of milk, a cup of yoghurt, one slice of cheese or a teaspoon of butter.
Current international healthy eating guidelines suggest that people should eat between two and four portions of fat-free or low-fat dairy products such as skimmed milk each day and limit whole fat dairy intake to prevent heart disease.
The researchers conclude that regions with the lowest intake of dairy, including south Asia, south-east Asia and Africa, should not be discouraged from eating such foods “and should even perhaps be encouraged” to eat more whole fat products.
Dr Mahshid Dehghan, of Canada’s McMaster University, the report’s lead author, said the findings suggested “that consumption of dairy products might be beneficial for mortality and cardiovascular disease, especially in low-income and middle-income countries where dairy consumption is much lower than in North America or Europe”.
But experts warned it would be premature to change dietary guidance based solely on the study, which included data from 136,384 people aged between 35 and 70 in 21 countries, ranging from Argentina to Zimbabwe.
Higher intake of milk and yoghurt — more than one serving a day — was associated with lower rates of a combination of total mortality and cardiovascular disease compared with no consumption. With butter and cheese, the differences in this so-called “composite outcome” were not significant as intake was lower than for milk and yoghurt, the authors said.
More research should now be undertaken to discover the reasons for the findings, they said.
Strictures about low-fat dairy consumption were “based on the presumed harms of saturated fats on a single cardiovascular risk marker” — one form of cholesterol. “However, evidence suggests that some saturated fats may be beneficial to cardiovascular health, and dairy products may also contain other potentially beneficial compounds”, including amino acids and vitamins as well as unsaturated fats, said the authors.
In a statement issued in conjunction with the study’s publication, nutrition experts Jimmy Chun Yu Louie of the University of Hong Kong and Anna Rangan from the University of Sydney recommended caution about the findings and suggested dietary guidelines did not need to change yet.
The findings were not “the ultimate seal of approval for recommending whole-fat dairy over its low-fat or skimmed counterparts”, they said.
Victoria Taylor, senior dietitian at the British Heart Foundation, also warned against jumping to conclusions. The age range of the participants was wide and younger subjects would have been unlikely to die or have cardiovascular disease within the nine-year follow-up period, which could have affected the results, she said.