Study Finds Dairy Intake In Teen Years Lowers Chances of Endometriosis Diagnosis

If you're a teen with endo, you may want to snack on some yogurt. That's because adolescents who eat more dairy were less likely to get a laparoscopically-confirmed endometriosis diagnosis, according to a new study published in the American Journal of Obstetrics and Gynecology. And there's good news for dessert lovers: teens who ate one or more servings a day of ice cream had a 38% lower risk of endometriosis diagnosis when compared to those who ate less than one serving a week.¹

It's important to note that the research doesn't show a causal relationship. That means experts can't say if eating dairy as an adolescent directly lowers your chances of developing endometriosis. All they can say is that women who eat more dairy in their teen years — specifically yogurt and ice cream — are less likely to get diagnosed with endometriosis when they're adults. More research is needed to find a cause-and-effect.¹

Until then, this study is a positive step forward in understanding the relationship between food and endometriosis. If you want to know more, here's a rundown of the research.

Why was the study done?

Past research shows a link between diet, nutrients, and endometriosis. Studies found that adults who eat dairy are less likely to get an endometriosis diagnosis. One reason may be because calcium and vitamin D have an anti-inflammatory effect. But there wasn't any research to show if the same was true for teenagers. This is the first study of its kind to take a look at that relationship between dairy, adolescence, and adult-diagnosed endometriosis. The researchers wanted to know if there are dietary factors that a young woman can change to lessen her chances of getting endometriosis.^1,2

How was the study done?

The results were based on a prospective cohort study. That kind of research compares data among a group of smilier people over time. For this study, researchers from Harvard Medical School, Houston IVF, the Fred Hutchinson Cancer Research Center, among others, analyzed findings from the Nurses' Health Study (NHS) II. The NHS, now in its third generation, looks at major risk factors for chronic diseases in women.³ In 1998, when participants were 34-51, they filled out a questionnaire about their high school diet. Researchers revisited the results — 15 years apart — to see how many women had been diagnosed with endo.

What did the study find?

By 2013, there were 581 pre-menopausal women — out of 32,868 in the NHSII — who received a laparoscopically-confirmed diagnosis of endometriosis. Women who ate more than four servings of dairy a day during their adolescent years had a 32% lower chance of getting surgically-diagnosed with endo. Teens who ate two or more servings of yogurt a week had a 29% lower risk when compared to those who ate less than one serving a week. And, like I said earlier, a bowl or more of ice cream a day lowered the risk by 38%.¹

Limitations of the study

The participants recounted their adolescent diet when they were adults. So, all of the answers were based on memories. The study also didn't answer whether women with endo are more likely to be lactose intolerance when compared to the general population. And if dairy makes you sick, are you less likely to grab a glass of milk or bowl of ice cream? I know that I couldn't digest ice cream or dairy milk when I was a teen. A blizzard from Dairy Queen would give me diarrhea before I'd even finished it. And my endo symptoms got much better when, at 19, I gave up dairy for good.

They thought about the reverse causation, said Holly Harris, an epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle and one of the lead authors. Harris addressed this question in previous studies about dairy and endo.⁴ But she and her colleagues weren't able to explore that specific question in this study. "We could hypothesize that women with endometriosis, who report almost as many GI symptoms as gynecologic symptoms according to some studies, may identify their lactose intolerance earlier than someone without endometriosis due to a heightened awareness of pelvic pain/GI issues," Harris told me in an email. "And these issues are difficult to disentangle."

Like the rest of us, Harris hopes there is more funding for endometriosis in the future. And hopefully, new studies will look at GI symptoms and pain onset. That way we can get a better idea of how and when diet and endometriosis affect each other.