For years, experts have recommended low-fat dairy products over the full-fat versions, which are higher in calories and contain more saturated fat. Recent research, however, indicates that full-fat dairy may actually be healthier than its reputation suggests, and that people who eat full-fat dairy are not more likely to develop cardiovascular disease and type 2 diabetes than people who consume low-fat dairy. They may even be less likely to gain weight.
Now, new research published Tuesday in The Lancet, adds to that body of evidence.
The research suggests that eating dairy products of all kinds is associated with a lower risk of premature death, cardiovascular disease and stroke. “About three servings of dairy a day is associated with a lower risk of mortality and cardiovascular disease,” says study co-author Mahshid Dehghan, a nutrition epidemiology researcher at the Population Health Research Institute in Canada. “We are suggesting that dairy is healthy, and people should be encouraged to consume dairy.”
The Dietary Guidelines for Americans also recommend consuming about three servings of dairy per day, but specify that these foods should be fat-free or low-fat. The new research, however, suggests that full-fat dairy can also be part of a healthy diet. While there was stronger data for milk and yogurt consumption than butter and cheese, dairy eaters in the study consumed more full-fat than low-fat products, suggesting that these results apply particularly strongly to whole-fat dairy foods.
The observational study was based on data from about 136,000 adults who took part in the Prospective Urban Rural Epidemiology (PURE) study, which collected diet and health information from people in 21 countries on five continents. (The United States was not among them, but Canada was.) None of the people included in the study had a history of cardiovascular disease, and all of them completed a detailed dietary survey, which included questions about type and frequency of dairy intake. Over about nine years of follow-up, roughly 10,500 people either died or had a major cardiovascular issue, such as a heart attack or stroke.
Dairy consumption, the researchers found, was associated with a lower risk of both outcomes. Compared to people who didn’t eat dairy, those who consumed more than two servings per day had lower total mortality rates (3.4% versus 5.6%) and cardiovascular mortality rates (0.9% versus 1.6%). They also had lower rates of major cardiovascular disease (3.5% versus 4.9%) and stroke (1.2% versus 2.9%).
And among people who ate only full-fat dairy, those who consumed about three servings per day had lower mortality rates than people who ate less than 0.5 servings per day (3.3% versus 4.4%).
That finding suggests that vilifying whole-fat dairy solely because of its higher saturated fat content — even though plenty of research does link saturated fat to heart disease — may not capture the whole picture, Dehghan says.
“Focusing on low-fat is predominantly based on the assumption that saturated fat increases LDL cholesterol,” she says. “But dairy contains many other components [which may be healthy] — amino acids, vitamin K, calcium, magnesium. They can be fermented and have probiotics. We should not focus on a single nutrient.” And the rest of the diet matters, too; eating dairy is likely better than loading up refined carbohydrates, according to recent research.
The new research has several limitations. The study participants only completed one diet survey at the beginning of the research period, so the results did not capture changes in eating patterns over time. The follow-up period of nine years was also relatively short, in terms of measuring long-term health outcomes like cardiovascular disease. And observational studies can never prove cause and effect, only point out patterns and associations.
Plus, while patterns were consistent across regions, many of the countries in the PURE study are low- or middle-income. Residents of these nations tend to eat less dairy than people in wealthy countries, which may mean they stand to benefit more from increasing consumption than people in the U.S. and other developed areas. There also was not much data for people eating more than three servings of dairy per day, which means it wasn’t possible to say how very heavy consumption affects health.
Pharmaceutical companies including Boehringer Ingelheim and GlaxoSmithKline also helped fund the research, though they were not involved in the study’s design or production. GlaxoSmithKline makes Horlicks, a milk-based nutritional beverage, while Boehringer Ingelheim’s animal health division makes medications for dairy cows.
An accompanying editorial written by Jimmy Chun Yu Louie, from the University of Hong Kong, and Anna Rangan, from the University of Sydney — both of whom have ties to Dairy Australia — says the study should not be treated as “the ultimate seal of approval for recommending whole-fat dairy over its low-fat or skimmed counterparts. Readers should be cautious and should treat this study only as yet another piece of evidence (albeit a large one) in the literature.”
Dehghan takes a similarly measured approach to the results, adding that the study is important in part because it broadens nutrition research beyond its traditionally North American and European epicenters.
“We are suggesting that dairy products should not be discouraged and perhaps even should be encouraged, especially in low- and middle-income countries where dairy consumption is low, or among individuals who consume very low amounts of dairy,” she says.
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