Are Low-Fat Dairy Products Really Healthier Than Full-Fat?

Scan the dairy case of any grocery store, and you’ll find rows upon rows of products with varying levels of fat. Nonfat, low-fat, whole: What’s the healthiest option?

If you consult the U.S. dietary guidelines or health authorities like the American Heart Association or the World Health Organization, the answer is clear: Choose a fat-free or low-fat version.

This recommendation stems from the idea that full-fat dairy products are high in saturated fats, so choosing lower-fat versions can reduce your risk of heart disease, said Dr. Dariush Mozaffarian, a cardiologist and professor of medicine at Tufts University.

But that guidance goes back to 1980, when the first edition of the Dietary Guidelines for Americans was published, he said. And since then, most studies on the health effects of dairy fat have failed to find any benefits of prioritizing low-fat versions over whole, Dr. Mozaffarian said.

What seems to be more important than the level of fat, he added, is which dairy product you choose in the first place.

What the research suggests

In studies that have surveyed people about their diets and then tracked their health over many years, researchers have found associations between dairy consumption and lower risks of certain conditions, such as high blood pressure, cardiovascular disease and Type 2 diabetes, Dr. Mozaffarian said.

Such benefits, he added, were often present regardless of whether people chose reduced-fat or full-fat yogurt, cheese or milk. And though full-fat dairy products are higher in calories, studies have found that those who consume them aren’t more likely to gain weight.

In one study published in 2018, for example, researchers followed 136,000 adults from 21 countries for nine years. They found that, during the study period, those who consumed two or more servings of dairy per day were 22 percent less likely to develop cardiovascular disease and 17 percent less likely to die than those who consumed no dairy at all. Notably, those who consumed higher levels of saturated fat from dairy were not more likely to develop heart disease or die.

In another large analysis, also published in 2018, researchers pooled the results from 16 studies involving more than 63,000 adults. They found that, across an average of nine years, those who had higher levels of dairy fats in their blood were 29 percent less likely than those with lower levels to develop Type 2 diabetes.

This finding suggests that there may be a benefit to consuming dairy fat rather than avoiding it, Dr. Mozaffarian said.

Of course, these studies can’t prove that dairy products themselves reduce certain risks of disease. That would require long-term clinical trials, which haven’t been conducted, Dr. Mozaffarian said. But shorter-term trials have shown that consuming dairy products, including full-fat dairy, lowered the blood pressure of participants and did not increase weight or raise levels of LDL, or “bad cholesterol” — again suggesting that dairy fat is not harmful to heart health.

Why dairy fats could be good for you

There are several possible explanations for why dairy fats may not be as harmful as previously thought — and may even be healthful, said Dr. Ronald Krauss, a professor of pediatrics and medicine at the University of California, San Francisco.

Among the various types of saturated fats that can be found in foods, dairy products contain certain ones that appear to be neutral or beneficial for health, Dr. Krauss said, including those linked to reduced risks of Type 2 diabetes and coronary heart disease.

Milk fat is also naturally packaged in a unique structure called the milk fat globule membrane, said Marie-Caroline Michalski, a research director at the French National Research Institute for Agriculture, Food and the Environment. Components of this structure can help bind cholesterol in the digestive tract, potentially improving blood cholesterol levels.

It’s also becoming clear that certain types of dairy foods may be better for you than others, Dr. Michalski said.

Yogurt and cheese, for instance, appear to be most associated with health benefits. This may be because both are fermented foods, Dr. Michalski said, which can supply good bacteria to your gut. They also contain other beneficial molecules made during fermentation, including vitamin K, which is linked to heart health, Dr. Mozaffarian said.

Harder cheeses like Cheddar and Parmesan also seem to result in a more gradual absorption of fats into the blood than softer cheeses and butter, which can help you feel fuller longer, Dr. Michalski said.

Advice for the dairy aisle

Penny Kris-Etherton, a professor emeritus of nutritional sciences at Pennsylvania State University, said an independent panel of nutrition experts is currently reviewing the evidence on how saturated fat consumption affects cardiovascular disease risk. And that could lead to upcoming changes to dairy food recommendations in the United States, she said.

Until then, she thinks it’s best to aim for three servings of dairy per day as part of a balanced diet, as is recommended by the current dietary guidelines. Based on the most recent dairy fat data, however, it’s probably OK if one or two of those servings are whole-fat milk, yogurt or cheese, she said, noting that more than that could add up to too many calories.

Dr. Mozaffarian suggests incorporating at least one or two servings of yogurt and cheese per day, given these foods’ health benefits — preferably unsweetened versions to avoid added sugar.

As for what fat content you should go for, “choose whatever you like,” Dr. Mozaffarian said. Some studies suggest that there may be a benefit of consuming full-fat dairy products, “but I don’t think the evidence is convincing enough yet to make that a dietary recommendation,” he added.

Dr. Michalski prefers eating plain, whole fat yogurt; when you remove the natural fats, you lose some vitamins, such as vitamins A and D, as well as the “pleasure” and good texture, she said.

Instead of butter, Dr. Kris-Etherton encourages people to use plant-based oils like olive, canola or soybean oils, or margarines made from the same oils.

Butter and cream do appear to raise blood cholesterol levels more than other sources of dairy fat, Dr. Krauss said, and he recommends limiting them if you have high cholesterol.

And while there’s not good evidence that low-fat dairy products are a healthier choice for everyone, Dr. Krauss said, people respond differently to different foods. If you have high blood cholesterol, he added, it’s worth discussing your dairy choices with your doctor.