Diagnosing and treating endometriosis, a condition that plagues up to 10% of women, is a huge challenge. Medically, endometriosis presents itself as endometrial tissue outside the uterus, which can wreak havoc with a woman’s ability to become and stay pregnant, not to mention the excruciating pain it can otherwise inflict.
As a field, we’re not great at pinpoiting what causes endometriosis but we’ve begun to look at whether women can limit, or exacerbate, their risk by adjusting their diet. Unfortunately, most of those studies to date have been done on small samples sizes and have told us little.
This month a study of over 80,000 women was reported which assessed a woman’s in-take of fruits and vegetables and charted that against if, or when, she ultimately developed endometriosis.
What we like about the study is that it was conducted on a large population, recorded dietary habits over a long period (over a decade) and used a definitive and relatively consistent measure of endometriosis (e.g. confirmation at surgery).
The investigators had a lot of data on these women and were able to correct for those factors probably related to diet (e.g. smoking and age) known to coincide with developing endometriosis.
What The Study Showed
Women who consumed fruits at a higher level were far less likely to develop endometriosis. Women who consumed 3 or more servings of fruit per day recorded a 14% lower likelihood of developing endometriosis than women who consumed 1 or fewer portions per day. But consuming more than 4 portions per day showed no increased benefit. In the field, we call this a “threshold effect.”
To be more concrete, consuming citrus fruits drove most of the benefit. Women who consumed 1 or more servings of citrus fruits per day dropped their rate of risk by over 20% compared with those who consumed citrus fruits only once per week.
Investigators didn’t see the same effect in consuming vegetables.
When investigrators cast around for explanations for their findings, they wonder whether properties like Vitamin A and C inhibit the growth factors that push the endometrium's cells to spread.
Every study has its shortcomings and in this case the women self-reported (always subject to inaccuracy) their intake, the patient population could be construed as homogenous (nurses) and thus not representative of all women, and the endometriosis had to be surgically verified, which means we're drawing conclusions only from women who required surgery. That said, we find the benefits of the study far outweigh it's limitations and the findings deserve our attention.