Is milk good for you? Depends on your age, health and sex, studies say

Weight gain and milk

When it comes to weight gain, results are mixed. “Overall, the findings of prospective cohort studies and randomized trials do not show clear effects of milk intake on body weight in children or adults,” the review concluded.

Of course, there would be benefits to drinking milk in countries where malnutrition is an issue, so the overall quality of a person’s diet is key in making recommendations.

“If meat and dairy foods are included in the dietary pattern, choosing lean cuts and lower fat dairy options is preferred,” the committee advised.

Milk and disease

For adults, there are some negative associations between milk and health. Despite the fact that milk is recommended for “strong bones,” countries with the highest intakes of milk and calcium have the highest rates of hip fractures, according to the New England Journal of Medicine review. Studies also have shown no clear benefit of calcium in reducing bone fractures.

In regards to cancer, the review found high consumption of dairy foods was associated with an increased risk of prostate cancer and may contribute to endometrial cancer. But it appears to reduce the risk of colorectal cancer.

Any connection between diabetes or cardiovascular disease and milk intake is not clear. Experts say it’s often a case of what you eat in place of the food. For example, dairy intake may be lower risk for cardiovascular disease compared to red meat but higher risk when compared to plant-based sources of protein.

Overall, the review concluded that “the health benefit of a high intake of milk products has not been established, and concerns exist about the risks of possible adverse health outcomes,” Willett and Ludwig wrote. “Therefore, the role of dairy consumption in human nutrition and disease prevention warrants careful assessment.”

The final 2020 through 2025 US nutritional guidelines for adults and children will be released at the end of the year. Until then, experts suggested parents discuss their individual family risk with their health care provider to decide on the role of dairy in their family’s diet — whole or not.

Children and milk

Then, if the child is growing well, parents should switch to low-fat dairy products at age 2 to protect children from the risk of obesity and cardiovascular disease, according to existing US guidelines. (The UK, however, does not recommend skim milk for children under 5.)

The fear of obesity is real: Last year, a study by the World Obesity Organization predicted that the number of obese children around the world will grow from 150 million currently to 250 million by 2030.

Kids who drink full-fat milk could feel more full, or else there could be the chance that parents who drink lower-fat milk have kids who are bigger, a rationale known as “reverse causality,” explained study author Jonathon Maguire, an associate professor of pediatrics at the University of Toronto, in a prior CNN interview.

Maguire and his team will now conduct a randomized, controlled trial with 500 children under the age of 5 over a two-year period to see more directly whether the fat content of the milk they drink is a key factor in determining their weight. The researchers will account for the kids’ snacking habits, their starting weights and other factors that could affect weight.

It’s important we “understand the health effects of what we do with our children,” said Maguire, who led the Canadian study on obesity and milk types. “Parents are making these decisions on a day-to-day basis,” and they need evidence.

Jury is still out

Another confounding variable about dairy research is the quality of the studies that have been done.

Many of the studies on milk and dairy are “observational” studies, which is a type of research that can only find an association between two outcomes; it cannot establish cause and effect. Randomized controlled trials — the gold standard of science — are expensive and difficult to do in nutrition.

“But that was because they were eating more tortillas along with the reduced-fat milk, so they were getting the same numbers of calories,” Hannon, who was not involved in the study, said.

On the other hand, “whole fat milk may lead to higher satiety, and therefore smaller portions and similar calorie intake,” said Christopher Gardner, a professor of medicine who directs nutrition studies at Stanford Prevention Research Center.

“I think the bigger questions are: Are either of them — whole or reduced fat — ‘good’ for you? And what would you be drinking instead of milk?” said Gardner, who was not associated with the study. “If it’s milk versus soda, I would pick milk. If it’s milk versus water, I’d pick water.”