Switching to Plant Milk? Here's What You Should Know

Newswise — Whether due to environmental concern, veganism, allergies, or because they simply like the taste, more and more Americans are choosing plant milk options instead of cow’s milk. But from a nutritional quality point of view, plant milks, such as oat milk, soy milk, almond milk, or coconut milk, aren’t a one-to-one match.

Alice H. Lichtenstein, senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) and the Stanley N. Gershoff Professor of Nutrition at the Friedman School of Nutrition Science and Policy, and Diane McKay, assistant professor at the Friedman School, recently shared their advice for people interested in making the switch. “A lot of people assume that plant milks are the same as dairy milk or cow milk, and that assumption is absolutely incorrect,” McKay said. “They are not nutritionally equivalent.”

A Medley of Milks

Plant milks are derived from plant products such as oats, soybeans, almonds, coconuts, rice, or hemp seeds. These plant products are ground up and soaked in water, then filtered to remove solids. The resulting liquid has a nutritional profile that is very different than cow’s milk and even different than the original plant product. Eating a bowl of oatmeal, for example, does not deliver the same nutrients as drinking a glass of oat milk. 

Cow’s milk is the primary source of calcium and vitamin D in most Americans’ diets. It’s also a high-quality source of protein, Lichtenstein said. Most plant milks, on the other hand, contain far less protein, and that protein is of lower nutritional quality. Soy milk is similar to cow’s milk in terms of protein but does not naturally contain calcium or vitamin D, hence, must be fortified with these nutrients during the manufacturing process. All other plant milks also need to be fortified with calcium to match the nutrition content of cow’s milk, Lichtenstein said. She adds that all milks, cow and plant, are fortified with vitamin D. 

Those seeking a low-sugar diet should be aware that flavored plant milks tend to contain added sugar, Lichtenstein said.

Healthy Choices

Thinking about plant milk and cow’s milk on a spectrum of healthy to unhealthy isn’t very helpful—plant milks aren’t inherently healthier or less healthy than cow’s milk, said McKay. Much more research is needed to link any specific types of plant milk to health outcomes. Because there are so many types of plant milk, and even those made from the same plant product can vary in their nutrition content, it’s “hard to draw firm conclusions about the health benefits of plant milk,” McKay said.

Plant milks are more processed than cow’s milk, which may be of concern to consumers looking to avoid processed and ultra-processed foods for health reasons, Lichtenstein said, as dietary patterns higher in ultra-processed foods tend to be associated with worse health outcomes as those that contain primarily whole foods.

Because plant milks are naturally more watery, manufacturers may also add thickening agents or stabilizers, such as calcium phosphate, disodium phosphate, and carrageenan. While most people have no problem digesting these thickening agents, some can experience stomach upset, McKay said. “Try another product if something is not sitting well with you,” she said.

McKay pointed out that there are some nutrition advantages to plant milks, too: Some can be a better source of fiber and vitamin E than cow’s milk, for example. 

How to Make the Switch

Consumers should be careful when searching grocery store shelves, as there’s a huge variability in the contents of plant milks, McKay said. Even under the same brand, some may come with differing amounts of added sweeteners or fortification. “There's so many different manufacturers of plant milks, and products vary greatly in things like their protein content, their calcium and vitamin D content, their B12 content, and more,” she said. 

The best way to tell what’s in your plant milk is by reading the nutrition label and ingredient list on the package. Ingredient lists are written in order of which ingredient is most prevalent—if sugar is the second or third ingredient, for example, that could mean that the product is higher in added sugars than you may want. 

McKay and Lichtenstein recommend relying on the United States Department of Agriculture for dietary advice. The only plant milk recommended by the USDA’s Dietary Guidelines for Americans is unsweetened, fortified soy milk, which contains added calcium, vitamin D, and vitamin A. Don’t take nutrition advice from social media, Lichtenstein added. And if you do see nutrition recommendations online, ask yourself what evidence the person is providing or whether they’re trying to sell a specific product. “If the claims are too good to be true, usually they are,” she said.

People who choose to stop consuming cow’s milk don’t have to replace its nutrients with other milks, either, Lichtenstein said. Instead, they can obtain similar nutrients by adding nutrient-rich foods to their diet. For example, vitamin D can be obtained from fortified breakfast cereal, fish, eggs, and irradiated mushrooms, which have been exposed to UV light to increase their vitamin D content. To add calcium, choose dark leafy greens, canned fish such as sardines, and some nuts.

“Just know you’ll need to make some adjustments to your diet to make sure that you're getting enough of the essential vitamins and minerals that are present in cow's milk,” McKay said.