As someone who writes and teaches about cheese, I hear a lot from the lactose intolerant. Whenever I do a book signing or presentation, people tell me—often with a gloomy expression—that they are lactose intolerant and can’t eat cheese. I know that aged cheese doesn’t have much if any lactose, but I’ve never been confident enough of my facts to know how to respond.

How fortunate, then, that I had Jeff Broadbent (pictured below) as my judging partner at the recent American Cheese Society competition. Jeff is a professor of dairy microbiology at Utah State University and an expert on lactic-acid bacteria (and, therefore, on lactose, which the bacteria eat). On the phone after the ACS conference, Jeff guided me through some of the myths and truths about lactose intolerance.

Some facts: Cow’s, goat’s and sheep’s milk all contain roughly the same amount of lactose (milk sugar), about 12 grams per cup. Our digestive system produces lactase, an enzyme, to break lactose down into the simple sugars we can digest. Some people gradually lose the ability to make lactase, and these folks experience gastric distress when they consume more lactose than their system can handle. The condition is more common among people of African, Asian, Hispanic or Native American descent. Lactose intolerance is not a milk allergy. People don’t die from it although reactions can be quite uncomfortable. And the degree of tolerance varies. Some lactose-intolerant people can manage a bowl of ice cream; others can’t.

But here’s what many lactose-intolerant people don’t know: When milk is coagulated for cheese, 98 percent of the lactose is removed with the whey. And in all but a few cheeses—high-salt ones like feta—the remaining lactose is quickly consumed by bacteria in the cheese.

“I can confidently say that bacteria-ripened, surface-ripened or mold-ripened cheeses that are not known for an intense salty flavor (think feta) will not present a problem for lactose-intolerant consumers,” Jeff told me. “By the time these cheeses reach store shelves, residual lactose will have been fermented by the microbes in the cheese.”

Unless you’re a cheese nerd, you may not know that “bacteria-ripened, surface-ripened or mold-ripened” covers virtually every cheese aged more than a couple of weeks. Jeff told me about a Cheddar study demonstrating how quickly lactose is used up. “Within a week, it’s essentially gone,” he said. “Certainly within two weeks.” Ramping up the salt in the Cheddar, as the researchers did, will slow this process, but then the cheese will have other defects.

I figured that Jeff, in his line of work, hears the same refrain about cheese that I hear from lactose-intolerant people. I wondered what he told them.

“I ask them, ‘What kind of cheese are you eating?’” he said. “If they’re eating ripened cheese, there’s no lactose in there.” Even 10 ounces of feta—a ridiculous portion—has less lactose than an 8-ounce glass of milk, which most lactose-intolerant people can drink without trouble. For less-salty cheeses (i.e., almost everything), a consumer “would have to eat a boatload of cheese to get much lactose,” says Jeff.

I have no interest in trying to persuade people to eat cheese if they’re disinclined. But those who consider themselves lactose-intolerant and would like to enjoy cheese occasionally might follow Jeff’s counsel. “I would steer them toward semi-hard varieties and encourage them to start with small portions,” advises the scientist. “If that really does cause problems, it’s not because of the lactose.”