“Drink your milk.” That’s an admonition every smart mother has given her children.

The vitamins, minerals and protein a glass of milk provides children as they grow into adolescents and adults cannot be replaced by energy drinks, fake “milk” or other beverages.

Everyone knows that.

But there’s a problem. More and more children and teenagers aren’t drinking their milk, or enough of it.

According to the USDA Economic Research Service, the per capita consumption of milk is trending downward, so much so that fewer Americans are keeping up with federal dietary recommendations.

In fact, “about 90% of the U.S. population does not consume enough dairy products to meet federal dietary recommendations,” according to the report.

Under those guidelines, children 2 to 10 years old should drink 2 to 3 cups of milk a day, or eat an equivalent amount of other dairy products. People older than 10 should drink 3 cups of milk a day or eat the equivalent amount in dairy products.

The report’s authors, Hayden Stewart, Fred Kuchler, Diansheng Dong and Jerry Cessna, say the decline has continued for more than 70 years. Since 2010, however, the decline in milk consumption has steepened to an average of 2.6% a year.

But why?

It’s complicated, the researchers said.

“We considered factors raised by researchers, industry analysts, policy advocates, the media  and economic theory,” the ERS researchers said. “These include competition between milk and alternative beverages through product innovations, decreases in cereal consumption, changes in school lunch and breakfast programs and changes in retail prices.”

Each of those factors is important, not only to the health of American children but to the dairy industry.

The competition among beverages alone is staggering. Many of the beverages children and teens drink these days didn’t even exist 5 or 10 years ago. They are also primarily marketed to teens and young adults.

Many breakfast cereals have also fallen out of favor, taking milk consumption down, too.

The good news is fluid milk represents only a portion of overall dairy consumption. Other dairy products are gaining in popularity.

For example, cheese consumption in 2019 was up 80% compared to 1975. Butter consumption was up 32% and yogurt consumption was up 570% during the same period, according to the Center for Dairy Excellence.

“The fact of the matter is, per capita consumption of dairy is the highest it has been in several decades,” according to the center.

Those are the success stories. But the fact of the matter is that more milk and other dairy products served with school lunches and other meals at home and in restaurants will lead to greater consumption as those students grow up.

People who drank milk as children will continue to drink it as adults, the ERS researchers said.

The best way to bolster the health of generations of Americans to come is to make sure they continue to get the message: Drink your milk.