Is cheese good for everyone

A version of this article originally appeared in the November 2015 issue of SELF.

An ice-cold glass of milk was once the beverage equivalent of comfort food: wholesome, quintessentially American. It paired perfectly with cookies and completed a healthy breakfast. These were facts that you probably didn't question as a kid. I know I didn't, coming of age in the "Got Milk?" era, when 300 celebrities (from Salma Hayek to Kate Moss) wore milk mustaches to remind us how important it was to drink up.

Today, I eat Greek yogurt for breakfast and gulp organic (full-fat!) chocolate milk after working out. My husband got me a fancy cheese grater last Christmas because I firmly believe that everything tastes better with Parmesan. But I find myself among an ever-shrinking minority of dairy-loving Americans. More and more of my friends are giving up cheese because they say it messes with their skin or their stomach, or switching to raw milk because they swear it clears up their allergies. Celebs like Alicia Silverstone and Megan Fox—who have espoused vegan or paleo diets—trumpet the supposed evils of dairy. Since 1978, Americans' milk intake has dropped from nearly a cup per day to a little more than half; 54 percent of us no longer drink it daily at all.

But what facts justify this widespread milk mutiny? "It can be difficult to wade through the information and know which sources to trust," says Lisa Sasson, R.D., a clinical associate professor of nutrition at New York University. So I dove into the research to sort through the myths and hype on both sides of the dairy divide.

What You've Heard: "Milk is the best source of calcium."

True, milk provides a lot of calcium. But it's not the only source—and how much calcium you need is a matter of some debate.

A serving of nonfat milk provides 30 percent of our RDA of calcium, according to the National Institutes of Health. The NIH advises women ages 19 to 50 to consume 1,000 milligrams per day—nearly impossible without dairy. (Women under 30, who are still actively building bone, are most in need of calcium.) But the World Health Organization suggests just 400 to 500 mg of calcium per day for all adults, or roughly the amount you'll get if your meals include kale, beans and two packets of instant oatmeal (without milk). Tofu, broccoli, sardines, almonds and calcium-fortified orange juice are additional sources. "If you're eating a nutrient-rich diet, you'll get calcium through lots of foods," Sasson says. (As for bone health: Leafy greens and weight-bearing exercises help, too.)

It's worth noting that the USDA not only oversees American dietary guidelines but also promotes the sale of American agricultural products—including dairy, explains David Katz, M.D., director of the Yale-Griffin Prevention Research Center in Derby, Connecticut. Some experts believe the USDA-recommended three daily servings of dairy may actually be too much. Walter Willett, M.D., chairman of the nutrition department at the Harvard School of Public Health in Boston, says that "preventing bone fractures has always been the primary justification for drinking milk." But when his team reviewed six studies of almost 200,000 women, they found no relationship between drinking milk and lower rates of fractures. And a study of 60,000 Swedish women found those who drank 21 daily ounces or more had a 60 percent higher risk of hip fracture (possibly due to a milk sugar that may have a weakening effect on bones).

What You've Heard: "You need milk for vitamin D."

Vitamin D—critical for calcium absorption and bone health and thought to be helpful in mood and weight regulation—is added by manufacturers to every cup of milk, as well as to some cheese and yogurt. That's because few foods contain vitamin D naturally; sources are limited to egg yolks, beef liver, and fatty fish. But dairy isn't the only food that's routinely boosted with D: fortified OJ and some cereals are other options. (The sun is the OG source, but exposure increases your risk for skin cancer and premature aging.) It's not clear that more D—beyond the 600 IU per day recommended by the NIH—is always better. Healthy adults who took vitamin D supplements didn't see any significant improvement in bone mineral density, according to a 2014 meta-analysis. Still, if you avoid dairy, talk to your doctor about the right D levels for you.

What You've Heard: "Chocolate milk is a perfect post-workout recovery drink."

Chocolate milk made its name as a great post-workout food because the protein in milk (8 grams, or 17 percent of the RDA for women) is said to be key for rebuilding muscle fibers frayed during workouts, while the sugar in chocolate syrup or powder replenishes fuel stores. I found a dozen studies validating these claims—and then noticed that about half of them were funded by the National Dairy Council. While non-industry-affiliated experts I talked to were wary of possible conflicts of interest in some chocolate milk research, they didn't dispute that it's important to replace fluids and glycogen stores after a hard workout. Research also supports the value of protein for muscle recovery. Yet chocolate milk is high in calories (if you drink it, you may want to opt for low-fat milk), and recovery fuel may not be necessary after less intense workouts. "If you eat a balanced diet, your body has what it needs," says Dr. Katz.