Dairy products may benefit cardiovascular health, says new research.
However, new research is challenging these guidelines.
Now, a large-scale observational study has reviewed the dietary habits of over 130,000 people in 21 countries across five continents and found that whole-fat dairy correlates with a lower risk of mortality and cardiovascular disease.
Dr. Mahshid Dehghan — from McMaster University in Ontario, Canada — is the lead author of the new research.
Whole-fat dairy lowers mortality risk
Dr. Dehghan and colleagues used food questionnaires to collect self-reported data on the eating habits of 136,384 people over a follow-up period of 9.1 years. The people surveyed were aged between 35 and 70, and the dairy products they consumed were milk, yogurt, and cheese.
For the purposes of the study, a portion of dairy comprised either a glass of milk of 244 grams, a cup of yogurt of 244 grams, a 15-gram slice of cheese, or a 5-gram teaspoon of butter.
Based on these intakes, the team divided the volunteers into four groups: those who consumed no dairy, those whose intake did not exceed one serving per day, those who consumed one to two servings daily, and the "high-intake" group, who consumed over two daily servings — or 3.2 servings, on average — every day.
The study revealed that people in the high-intake group were less likely to die from any cause, less likely to die of cardiovascular disease, and less likely to have a stroke or develop major heart disease.
Also, within the group that regularly consumed full-fat dairy only, the researchers found that the more whole-fat dairy was consumed, the lower the risk of mortality and cardiovascular issues.
"Our findings support 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."
Dr. Mahshid Dehghan
Should dietary guidelines be changed?
Although this is an observational study that cannot confirm causality, the results suggest that some saturated fats in whole-fat dairy could benefit cardiovascular health, as do some vitamins and calcium. Does this mean that the current dietary guidelines should be changed?
Previous research that found similar results suggested that the guidelines do need revising. However, a linked commentary written by Jimmy Chun Yu Louie, at the University of Hong Kong, and Anna M. Rangan, from the University of Sydney in Australia, explains why that may not be such a good idea yet.
"The results from the [...] study seem to suggest that dairy intake, especially whole-fat dairy, might be beneficial for preventing deaths and major cardiovascular diseases," they write.
"However, as the authors themselves concluded, the results only suggest the 'consumption of dairy products should not be discouraged and perhaps even be encouraged in low-income and middle-income countries.'"
"[The study] is not the ultimate seal of approval for recommending whole-fat dairy over its low-fat or skimmed counterparts," they add. "Readers should be cautious, and treat this study only as yet another piece of the evidence (albeit a large one) in the literature."