New research says cow's milk is better for you than oat milk or other plant-based vegan alternatives

• Cow's milk and non-dairy milk are not nutritionally equal, according to new research.
• Scientists found that plant-based milks often have less vitamin D, calcium and protein.

The plant-based milk industry is booming, and new milks seem to be cropping up everywhere — from the old standbys of almond milk and oat milk, to newfangled pistachio milk and cashew milk. The options are endless.

But few of these alternatives compare to cow's milk in terms of nutrition, according to data presented on July 24 at the American Society for Nutrition Conference in Boston. The data has not yet been published.

"I thought going into this that the manufacturers would have been looking at cow's milk and trying to match it with these products," Dr. Abigail Johnson, who researches nutrition at the University of Minnesota, told Insider.

Instead, there's so much variability in the nutritional content of non-dairy products, "I think that the flavor and the mouthfeel and the other properties are probably what's mostly driving the development in these products and not so much like if they are a nutritional match for cow's milk," Johnson said.

Cow's milk is more nutrient dense than most plant-based alternatives

Scientists analyzed the nutrition labels for 237 plant-based milk products from 23 different manufacturers. But only 28 of the beverages were comparable or better than dairy milk when it came to vitamin D, calcium and protein.

Of the plant-based milks, oat milk was the plant milk most commonly fortified with calcium and vitamin D — 76% of the oat milks analyzed contained both nutrients. The runner ups were soy milks and almond milks. But the plant-based milks were highly variable.

Plant-based milks tended to have less protein than cow's milk as well — a fact that's "been known," said Johnson. Cow's milk contains 8 grams of protein per serving. Soy milk is typically equivalent in protein, but other plant-based milks contain only 2 grams of protein on average, Johnson said.

Some experts, however, are skeptical of the study's findings. Dr. Christopher Gardner, director of the Stanford Diabetes Research Center, told CNN that the assertion that cow's milk is nutritionally superior is "bunk."

"None of the plant milks have cholesterol, they all have very low levels of saturated fat, and some of them have fiber," he told CNN. Plus, "dairy milk has cholesterol, has saturated fat and does not have fiber," which can make plant-based milk better for some people.

Oat milk fans don't need to despair yet

Although plant-based milks may be poorer sources of protein, vitamin D and calcium, you don't need to start drinking cow's milk if you don't want to.

Experts are not that concerned about protein, as most Americans get "ample protein as part of our diets," Johnson said.

If you're looking to get calcium and vitamin D from plant-based milk, "then you need to read the label to make sure that they actually provide what you nutritionally are looking for," said Johnson. "If you look at the label and the product that you have has both calcium and vitamin D on the label, it's highly likely that the amounts of calcium and vitamin D that have been added are similar to what's in cow's milk."

On the other hand, "if your product lists just calcium or just vitamin D, it's a little bit less likely."

"The biggest takeaway," said Johnson, is that plant-based milks are "not one to one matches for cow's milk." Johnson said that it's important to get both vitamin D and calcium in your diet but "where you get that can be from foods, or it could be from cow's milk, or it could be from an alternative source," she said.