Milk and milk products like yogurt and cheese are commonly recommended as part of a healthy diet. These foods provide good sources of protein, calcium and several other essential nutrients.
Because some dairy foods are high in fat and saturated fat, the lower-fat options typically are promoted as the most healthful options.
Like higher-fat milk products, eggs are commonly maligned as a food bad for heart health due to their cholesterol content. However, two new extensive reviews of the scientific research on milk and eggs question both of these common recommendations.
QUESTION: Do full-fat dairy foods adversely affect health when compared with low-fat and fat-free dairy foods?
ANSWER: A thorough evaluation of the scientific research on high-fat dairy products was published in the January issue of the British Journal of Nutrition. Researchers from both the U.S. and Switzerland evaluated relationships between dairy fat consumption and the risks of obesity, type 2 diabetes and cardiovascular disease. They found that most studies do not support the low-fat recommendations.
Q: Do high-fat dairy foods and eggs lead to obesity, diabetes and heart disease?
A: Studies that followed people over time did not find a consistent link between obesity and the consumption of high-fat dairy foods. Somewhat surprisingly, several long-term studies indicated that people consuming the most high-fat dairy foods gained less weight than those who consumed less high-fat dairy products.
Although it seems logical that lower-fat dairy products would be better for health (fewer calories and less fat and saturated fat), there are good reasons to question this assumption. During the past 40 years, while people in the U.S. largely switched from full-fat whole milk, yogurt and cheese to low-fat or skim options, the population steadily grew fatter. Would we be even fatter if we hadn’t made the switch? Several studies indicate we might actually be leaner.
Since the risks for diabetes and cardiovascular disease increase with body weight, it is not surprising the researchers found a lack of support for a link between high-fat dairy foods and the risk of developing diabetes or heart disease. Overall, there was more evidence that these foods may even be protective.
Also in January, BMJ (previously British Medical Journal) published a major review of research studies on egg consumption and the risk of coronary heart disease and stroke. The authors reported that the results of their "meta-analysis" review "do not support that higher egg consumption is associated with elevated risk of coronary heart disease and stroke." Interestingly, the researchers found that higher egg consumption was associated with a reduced incidence of hemorrhagic stroke — the type caused by bleeding into the brain.
Q: Are the recommendations for choosing low-fat dairy products and avoiding eggs wrong?
A: These new reviews certainly argue that the recommendations need to be reconsidered. It can be difficult to translate a review of studies conducted in various parts of the world into recommendations for a single country. The results of these studies do suggest that we do not need to fear these foods.
Milk and eggs provide many nutrients and other components that can be important in an overall adequate diet. However, like any other type of foods, variety and moderation always make sense.
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Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.
