By Amanda MacMillan
Updated: February 9, 2018 8:48 PM ET | Originally published: January 30, 2018

That almond milk latte may be delicious, but a study just published in the Journal of Food Science and Technology suggests that the trendy beverage also has some drawbacks. When researchers compared the nutritional profiles of four popular “alternative” milks, they found that soy milk came out on top—and that almond, rice and coconut “milks” all lacked essential nutrients important for overall health.

Plant-based “milks” are often marketed as wholesome and appropriate substitutes for the real thing. To find out if these claims measured up, scientists at McGill University in Canada studied the nutrition labels of several unsweetened almond, soy and rice milks, plus coconut dairy-free beverages, on grocery-store shelves.

Cow’s milk, the researchers say, is still the most complete and balanced source of protein, fat and carbohydrates. Soy milk, a popular alternative option for more than four decades, was found to be the most comparable to cow’s milk in terms of overall nutrient balance. It’s also the highest in protein of all the alternative milk options studied, with about 7 to 12 grams (and about 95 calories) per 8-ounce serving.

Soy milk also contains phytonutrients known as isoflavones, which have been shown to have cancer-fighting properties. It’s not a perfect substitute, though; some people complain about its “beany flavor,” the authors wrote, and some scientists have expressed concerns about “anti-nutrient” substances naturally found in soy, like phytic acid, which can make it harder for the body to absorb and digest important vitamins and minerals.

Almond milk, on the other hand, is low in calories (about 36 per serving) and rich in monounsaturated fatty acids. Getting more of these healthy fats may be beneficial to weight loss and weight management, the authors wrote, and they have also been shown to reduce LDL—or “bad”—cholesterol. But almond milk is also low in protein and carbohydrates, making it less nutritionally balanced than cow or soy milk.

Meanwhile, dairy-free coconut beverages have no protein. And although it’s low in calories (about 45 per serving), most of that energy comes from saturated fat. On the plus side, the report states, drinking this type of beverage has been associated with increases in HDL—or “good”—cholesterol and reductions in LDL cholesterol.

Sweet-tasting rice milk can serve as an alternative for people with allergies to soybeans and almonds, but it’s high in calories (133 per serving) and relatively low in beneficial nutrients. Research suggests that “consumption of rice milk as an alternative to cow’s milk without proper care can result in malnutrition,” the authors wrote, “especially in the case of infants.”

MORE: The Case Against Low-fat Milk Is Stronger Than Ever

Cow’s milk, by comparison to the dairy alternatives, contains about 158 calories per 8-ounce serving, along with 8 grams of protein, 9 grams of fat (5.5 of it saturated fat), and 11.5 grams of carbohydrates. That’s the “perfect composition of nutrients” for baby cows, the authors wrote in their paper, and it’s similar to the composition of human breast milk.

Milk is also an important source of vitamins and minerals—including calcium, which the body needs for bone health, especially during childhood and adolescence. Most milk substitutes are fortified with calcium to mimic the levels in cow’s milk, although the authors point out that “further research is needed to establish the consequences of added calcium in the human body.”

So why the need for alternatives? For one, dairy is one of the most common allergens among infants and children. Between 2% and 4% of children have a milk allergy (that’s more than peanuts or tree nuts), although as many as 80% may outgrow them by age 16. Plus, milk—especially raw, unpasteurized milk—has been linked to outbreaks of pathogens such as salmonella and E. coli around the world, suggesting that it’s not always the safest beverage for children or for adults.

Then there’s the issue of lactose intolerance. Somewhere between 15% and 75% of adults—depending on race, food habits and gut health—lack sufficient amounts of the enzyme needed to properly digest dairy products, according to the report. It’s even been estimated that up to 80% of people of African origin, and up to 100% of people of Asian and Indigenous American origin, are lactose intolerant.

Finally, while studies suggest that dairy products—even full-fat versions—can be a healthy part of a balanced diet, some people may not want to overdo it on high-calorie, high-fat cow’s milk. For all of these reasons, the authors say, consumers should know how popular milk substitutes compare.

“It is quite clear that nutritionally soy milk is the best alternative for replacing cow’s milk in human diet,” they concluded in their paper. They acknowledge, though, that more people may enjoy the flavor of almond milk. Those who choose the latter should make sure they’re getting enough essential nutrients, like carbs and protein, through other sources in their diet, they write.

That should be easy enough for adults, says lead author Sai Kranthi Kumar Vanga, a PhD candidate in McGill’s department of bioresource engineering, since they can also get protein from meats, nuts and beans, and healthy fats from sources such as olive oil. It can be more difficult, he adds, for babies and young children with dairy allergies. “Parents have to monitor their diet and provide them with appropriate alternatives for the lost nutrients, which is not easy,” he wrote in an email.

And while swapping out a few tablespoons of milk in your coffee every day won’t make a big difference in overall nutrition, Vanga says there could be implications for adults who consume considerably more milk—like every morning with their cereal. “Just replacing your cow’s milk with one of the plant-based milks and assuming it’s fulfilling the nutritional requirement could lead to health complications in the long run,” he says.

Contact us at editors@time.com.

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