Milk is a good source of calcium but isn’t necessarily the most critical factor for bone health, according to a Stanford researcher who recently discussed the facts and “facts” about milk.
August 17, 2018 - By Jennifer Huber
Milk used to be simple. Your local dairy, say Berkeley Farms, delivered it to your doorstep.
Today, we are faced with an unfathomable array: nonfat, low-fat or whole milk? Almond, soy, rice, hemp or oat milk? From goats or cows? With or without the lactase enzyme? Raw or pasteurized? Plain or flavored? There’s even an ongoing controversy over which of these drinks can be called milk.
Stanford nutrition scientist Christopher Gardner, PhD, wants to help consumers cut through the confusion. In an interview, he discussed some of the biggest misconceptions about the beverage.
Most of us grew up believing that milk is important for children to build strong bones and for the elderly to prevent osteoporosis. But milk, a good source of calcium, isn’t necessarily the most critical factor for bone health, said Gardner, the Rehnborg Farquhar Professor and a professor of medicine.
“There are countries like Japan and India where the population is predominantly lactose-intolerant, where milk intake is low and hip fracture rates are also low. But many of those cultures do more weight-bearing activities than Americans,” he said. “It’s better to be physically active than drink milk as a way to strengthen your bones.”
Studies have shown that drinking milk can improve your bone density, but whether it helps prevent bone fractures is debatable, he added.
Do we need cow’s milk?
But don’t young kids need milk? According to Gardner, it depends on what kind of milk. Breast milk is incredibly important, but cow’s milk isn’t, he said.
“This myth goes way back to before the food pyramid when the National Dairy Council offered to provide nutrition material to schools for free. And in all those materials, they said that you need multiple servings of dairy every day for a healthy diet,” Gardner said. “That was never agreed on. A lot of people are lactose-intolerant, and you don’t need it.”
Milk can be healthier than other options, like soda. He recommended checking the nutrition panel to make sure the milk isn’t just as sugary as soda though, particularly with plant-based milks. “The popular vanilla and chocolate versions of the plant-based milks are often loaded with added sugar. Even the plain is typically sweetened, but you can get unsweetened,” he said. “The lactose in milk isn’t that bad, so there is no need to water it down. Just avoid milks with added sugars.”
The nutrition label also allows you to compare the amount of fats, protein, carbohydrates and vitamins in each type of milk. “For example, the plant-based milks generally don’t have saturated fat like cow’s milk, so they don’t raise LDL-cholesterol as much as dairy milk, but they do have about the same amount of calcium,” he said. “And soy milk has the same amount of protein as dairy milk, but almond milk has much less protein.”
Another common misunderstanding is that 2-percent milk means that 2 percent of the calories are from fat. Really, it means that 2 percent of the weight is from fat. In 2-percent milk, 35 percent of the calories are from fat, Gardner noted. “Whole milk has close to 50 percent of its calories as fat, and 1-percent milk has about 20 percent,” he said.
Does milk help with weight loss?
However, your milk’s fat content may not affect your weight. The old belief was that drinking whole milk will make you fat and skim milk will help you lose weight. But this was refuted by Harvard’s Nurses’ Health Study, which followed the diets of over 100,000 nurses for more than 30 years, including how their diets changed.
“The Harvard study found that switching back and forth from whole-fat to 2-percent to 1-percent was not associated with changes in weight,” Gardner said.
But does drinking more milk help with weight loss? Some small, short-term studies showed that people lost weight if they drank more milk. According to Gardner, this raises the always-present nutrition-research challenge: Was it drinking more milk or was it consuming less of something else that caused the weight loss?
And what about raw milk? Raw milk proponents argue that pasteurization kills off important healthy bacteria, but Gardner said that it’s difficult to prove any health benefits from these bacteria. Some raw milk producers also claim it is easier to digest. However, a study overseen by Gardner found that lactose-intolerant participants had the same symptoms with raw and pasteurized milk.
And what does Gardner himself drink? He said he gave up cow’s milk for ethical reasons.
“Now, I drink unsweetened soy milk,” he said. “In our household, my wife doesn’t digest dairy milk very well, so we don’t even have it around. My four boys all drink unsweetened soy milk.”
Stanford Medicine integrates research, medical education and health care at its three institutions - Stanford University School of Medicine, Stanford Health Care (formerly Stanford Hospital & Clinics), and Lucile Packard Children's Hospital Stanford. For more information, please visit the Office of Communication & Public Affairs site at http://mednews.stanford.edu.