Several years ago, after an acquaintance asked me if I'd heard about the controversy, I Googled "cow's milk" and "kids" and a new world opened up to me — one that hysterically warned me that cow's milk would cause my child to develop diabetes, obesity and cancer, among other lovely things. I decided that until I learned more, I would switch my toddler from cow's milk to a 50/50 mixture of cow's and almond milk. Just, you know, in case. I'm not alone: Many parents are questioning the conventional wisdom of feeding kids cow's milk, turning instead to alternative plant-based "milks" such as soy, almond, cashew, rice, or coconut milk, which they believe are healthier.
But the science suggests that this "controversy" is pointless, for several reasons. Although cow's milk isn't perfect, many of the scary claims made about it are overblown. Compared with many plant-based "milks," the milk that comes from a cow typically has more nutrients and fewer unhealthy additives. And really, there's no need to stress about milk anyway: The idea that toddlers and older kids need milk and are going to suffer without the right kind is silly. Milk provides important nutrients, but if your kid eats a balanced diet and stays hydrated, she doesn't need it at all.
Cow's milk is chock full of calcium, vitamin D, and protein. In one glass, a kid gets as much protein as he would eating three slices of deli turkey. He also gets nearly 40 percent of the recommended amount of calcium for children ages 1 to 3 and 20 percent of the recommended amount of vitamin D. The U.S. Department of Agriculture recommends that kids and adolescents, depending on their age, consume 2 to 3 cups of dairy products a day.
Plant-based milk alternatives deliver some of these nutrients, but generally not all of them. Almond and cashew milks are calcium-fortified, and they also have lots of vitamin D, but they are quite low in protein. As for soy, coconut and rice milks, it depends on the brand. Soy milk typically has as much protein as cow's milk does, and some brands are fortified with calcium and vitamin D; rice and coconut milks are typically low in protein but can, again, be enriched with calcium and vitamin D. (One other good thing about soy milk: Research suggests that consuming a serving or two of soy foods a day during childhood and adolescence could protect against breast cancer later in life.)
Though plant-based milks are sometimes celebrated for having less saturated fat than milk, evidence to date suggests that fat is not the nutritional villain it was once believed to be. So basically: Cow's milk is the most consistently nutritive of the lot.
You would think that milks made of nuts would be more protein-rich than they are. Last year, in a piece titled "Lay Off the Almond Milk, You Ignorant Hipsters," Mother Jones' Tom Philpott calculated that an entire 48-ounce jug of Califia Farms almond milk contains the same amount of protein as a mere handful of the nuts. His conclusion: "The almond-milk industry is selling you a jug of filtered water clouded by a handful of ground almonds."
Consumers have filed a class-action lawsuit against the makers of Almond Breeze, alleging that they falsely market the drink as if it is primarily made from almonds when, in fact, it is composed of only 2 percent almonds, with water, sugar and additives making up most of the rest.
Another problem is that plant-based "milks" are often loaded with added sugar. The "vanilla" flavor of Silk almond milk contains 16 grams of sugars per serving, which is equivalent to about 4 teaspoons of table sugar. Even the "original" flavor packs 7 grams of sugar in each serving. Cow's milk contains sugar, too — 13 grams per serving — but at least this is in the form of a naturally occurring sugar, lactose, whereas the sugars in other types of milk are typically added for taste.
Ultimately, plant-based milk alternatives "are of varying quality, expensive, often full of sugar, low in fat and protein, and are fortified with synthetic vitamins," says Natasha Burgert, a pediatrician in Kansas City, Mo. Not so appealing anymore, huh?
Of course, cow's milk isn't perfect either. For one thing, it is very low in iron, and the calcium in it also inhibits iron absorption. (Calcium-fortified plant milks do the same.)
What's more, all those claims you hear about milk being crucial for bones are a little thin on evidence. In 2014, researchers at Harvard University and other institutions published the results of a study in which they followed 96,000 men and women for 22 years starting in adolescence. After controlling for other factors, they found that the amount of milk the subjects drank during their teen years had no effect on their risk of hip fractures as they got older. Other studies suggest that exercise and body mass index have a much bigger effect on children's bone health.
Some observational studies have also found that people who drink a lot of milk are more likely to develop certain cancers. These types of studies are, however, difficult to interpret, because people who drink milk may be different in myriad ways from people who don't. Cow's milk does contain a growth hormone called IGF-1, which has been tied to increased cancer risk, but scientists say that drinking milk increases IGF-1 levels in the human body so minimally, if at all, that it's unlikely to explain the association.
Another growth hormone that often gets mentioned in fearful conversations about cow's milk is recombinant bovine growth hormone, or rBGH (also called rBST), which is injected into some dairy cows to increase their milk output. Studies have found no differences between milk made by untreated versus treated cows, and it's important to note that cows make this hormone naturally anyway.
There is one good reason to question the wisdom of rBGH use, though: Research suggests that treated cows are more likely to develop udder infections called mastitis, which require antibiotics and may contribute to the growing problem of antibiotic resistance. The majority of milk sold in the United States is made from cows that have not been treated with rBGH, but if you're concerned or don't want to support the practice, Google lists brands of milk produced from non-rBGH-treated cows. And as for the claim that milk will cause kids to develop diabetes, the bulk of the risk comes from feeding large quantities of cow's milk to babies under the age of 1, which the American Academy of Pediatrics recommends against.
Cow's milk isn't going to endanger your kid (unless it is unpasteurized — please don't feed your kids raw milk!), and it's better than a lot of plant-based alternatives. But this doesn't mean you have to pour milk down your kid's throat or worry if your kid can't have it — in fact, many pediatricians tell parents to take it easy on the milk, especially if kids eat a lot of cheese or yogurt, because children who are constantly chowing down on dairy may not ultimately get a balanced diet.
As Natalia Stasenko, a pediatric dietician in New York City, explains, "If your toddler drinks four 8-ounce bottles (of milk) a day, he will have very little appetite for other nutritious foods and feel less adventurous at mealtimes." She suggests that parents replace milk "snacks" with solid foods and serve milk only at mealtimes.
Melinda Wenner Moyer is a science writer based in Cold Spring, N.Y.