This advice plus other advice to limit saturated fats rapidly led to a massive shift in America to use of low and no fat dairy products from whole fat diary. Unfortunately, for whatever reasons, today America has an epidemic of obesity, overweight, metabolic syndrome, diabetes and perhaps now an increasing incidence of cardiovascular disease.
Was the dairy advice correct or not? A recent perspective article in the J of the American Medical Association asked experts and suggests that the answer is simply not clear.
One observation is that Americans use cheese primarily to create pizzas, cheeseburgers and junk foods, while Europeans use cheese as cheese itself.
What is known about the health benefits or non-benefits is based on observational studies which amount to associations rather than clear cause and effect as would be found in a randomized trial where some group gets full fat diary and the other does not. Still, observational studies at least give directions for consideration.
In the PURE study of 136,000+ individuals 35-70 years of age, a higher intake of dairy fat was actually associated with lower risk of cardiovascular events and mortality. “Whole fat dairy seemed to be more protective than nonfat or low-fat dairy”
Another approach is to look at biomarkers, in this case by examining the blood content of three specific fatty acids are primary derived from dairy products. It turned out that when 16 such studies were pooled with 63,00 participants, those with higher levels of the three fatty acids were less likely to develop diabetes during the time of the trial.
What about weight gain? It turns out there is no clear-cut evidence that full fat dairy is more likely to lead to weight gain than low fat or no fat diary consumption. An expert quoted in the article noted that there is no strong data to show that full fat diary leads to more weight, more cardiovascular disease or more metabolic syndrome. Rather observational studies suggest just the opposite.
Another expert interviewed suggested that the key is not to worry about any one ingredient in the diet but what is most important is the overall dietary pattern. This makes good sense to me.
Rubin, R, Whole-fat or nonfat dairy? the debate continues, J Amer Med Assoc, 2018; 320:2514-2516