For decades, public health-oriented organizations like the American Heart Association have warned us all to be very careful about overindulging in whole milk or other full-fat dairy products. The AHA website recommends fat free (skim) milk, yogurt or cheese.

After all, cheese and whole milk contain saturated fat like that in butter. Experts assumed that dairy products rich in cholesterol would raise blood levels of cholesterol. They expected that to clog coronary arteries and result in a higher chance of heart attacks.

People actually heeded these warnings. Many consumers turned to milk substitutes based on plants such as soybeans or almonds. Others made sure that they bought only low-fat or nonfat yogurt.

What is the evidence that cheese, yogurt or whole milk are bad for you? As it happens, it is quite thin. Previous studies have not shown that people who drink whole milk or eat cheese are more susceptible to heart disease (European Journal of Epidemiology, April 2017).

A recent randomized controlled trial compared consumption of low-fat and high-fat dairy products over 12 weeks (American Journal of Clinical Nutrition, September 2021). The control group limited their intake of dairy products. All of the participants in this trial had metabolic syndrome. This constellation of high blood sugar, elevated cholesterol, high blood pressure and a large waist puts people at high risk for heart disease and diabetes.

Cardiologists might be surprised by the results of this study because they contradict conventional wisdom. There were no differences between groups with respect to LDL, HDL or total cholesterol, triglycerides or free fatty acids. The researchers concluded, “Therefore, dairy fat, when consumed as part of complex whole foods, does not adversely impact these classic CVD [cardiovascular disease] risk factors.”

This is not the first study to challenge the standard belief system about dairy fat. The Sydney Diet Heart Study ran between 1966 and 1973 in Australia. The results weren’t published for 40 years (BMJ, Feb. 5, 2013).

The researchers in this experiment assigned high-risk men to use either margarine or butter during that time. Men using safflower oil margarine were 60% more likely to die over the years of the study. The absolute risk of death from heart disease went from 10% on the butter-rich diet to 16.3% on the margarine-based diet.

Another trial pitting butter against margarine ran about the same time. The Minnesota Coronary Experiment involved more than 9,000 patients in mental institutions and a nursing home. The researchers had total control over the subjects’ diets. The test diets included one high in saturated fat and the other high in polyunsaturated fats from corn oil.

Like the Sydney Diet Heart Study, the results were not what the investigators expected. Perhaps that explains why the data were not published until much later (Atherosclerosis, January-February 1989). Patients on the corn oil diet had less cholesterol in their blood, but they were just as likely to die from heart disease.

If there is a moral to this ongoing controversy, it is that high-fat dairy products do not appear to be as dangerous as doctors once thought.

— King Features