Full-fat dairy is back. But nutrition experts say it might not be so simple

For decades, health experts have recommended Americans opt for non-fat and low-fat options in the dairy aisle.

But President Donald Trump and his administration are instead embracing whole milk and full-fat products as the preferred choice.

The new Dietary Guidelines for Americans, released on Jan. 7 by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services, recommends consuming full-fat dairy with no added sugars.

The president himself recently sported a white milk mustache in a social media post, telling Americans to "Drink Whole Milk."

Nutrition experts say the change comes after a growing number of studies have suggested that full-fat dairy products may not have the negative health effects that the medical community once thought.

Dairy, along with meat and coconut products, are rich in saturated fat. Consuming this fat has been shown to raise a person's level of Low-Density Lipoprotein (LDL) cholesterol, which increases their risk for developing coronary artery disease and other negative impacts on heart health.

But over the last decade, a number of studies have found that people who eat whole milk and full-fat yogurt are not more likely to develop heart disease.

Mario Kratz, a former academic researcher who studied the health impact of dairy foods while at the University of Washington, said the research doesn't explain how full-fat dairy impacts heart health.

"An observational study is always reporting an association between two variables," said Kratz, who now operates "Nourished by Science," a YouTube channel focused on nutrition and chronic disease prevention. "But at least it wasn't supportive of the hypothesis that eating more whole full-fat dairy foods would be likely to actually increase the risk of cardiovascular disease."

Some research has even found positive associations between consuming full-fat dairy and heart health. A study published last fall by researchers at the University of Minnesota School of Public Health found people in their 20s who consumed the most full-fat dairy products were the least likely to have early signs of heart disease two decades later.

Ethan Cannon, a Ph.D. student in epidemiology who is the study's lead author, said dairy foods are good sources of nutrients, especially vitamin D, calcium and potassium. But he said equally as important is what people are eating instead if they aren't consuming dairy products.

"When you think about the overall food environment out there, and all the, frankly, junk food that people are consuming, dairy products, both whole fat and low fat, would be doing more benefit than harm compared to some of the other options," Cannon said.

He said more research is needed to understand why consuming whole-fat dairy products has a different impact than other foods high in saturated fat.

This uncertainty is why some nutrition experts feel the recommendation to consume full-fat dairy products in the new Dietary Guidelines goes too far.

"This is such a complex subject," said Sander Kersten, director of the Division of Nutritional Sciences at Cornell University. "You can weigh the evidence very differently, and depending on how you do that, you end up with a different outcome."

U.S. Department of Health and Human Services/U.S. Department of Agriculture

Without clear evidence around how the body processes full-fat dairy, Kersten said he still favors a recommendation for consuming low-fat and nonfat products.

The new guidelines maintain the longstanding recommendation that saturated fat should not exceed 10% of a person's daily calories. But Kersten said achieving that level would be incredibly difficult if a person is also consuming more whole-fat dairy and beef like the guidelines recommend.

"They simply don't match. You're not going to be able to stay within that 10% if you follow those guidelines," he said.

That has led Kersten and others working in nutrition research to wonder whether some of the Dietary Guidelines changes were pushed by industry groups rather than scientific evidence.

"There have been examples in the past where these interest groups have used their leverage to try to impact the general guidelines and people's perception on dairy foods," he said.

Other experts, like Kratz, feel there is enough research to stop excluding full-fat dairy from nutrition guidance. He said if scientists can't decide what type of dairy is better, the choice should be left to the consumer.

But Kratz said not all full-fat products should be treated equally.

"If people think, 'Oh, dairy fat now is fine,' that could easily lead to people also just being much more liberal with butter and cream and ice cream," Kratz said. "I think we should be careful not to throw that into the same basket."

While the new Dietary Guidelines highlight butter and beef tallow as healthy fats, Kratz said there is no science to support that suggestion.

He said research has clearly shown that butter raises LDL cholesterol levels and is high in calories without providing any beneficial vitamins or minerals.

This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest and Great Plains. It reports on food systems, agriculture and rural issues.