In a study of more than 20,000 black women in the US, those who said they ate two or more servings of fruit each day were less likely to be diagnosed with uterine fibroids than women who barely touched fruit.
Fibroids don't always have symptoms, but can be painful or cause menstrual periods to be extra long and heavy. They can also grow to be very large, and in some cases may cause complications with pregnancy and fertility.
Black women are up to three times more likely to get fibroids than white women, and researchers have wondered if part of that could be explained by differing diet habits.
To try to answer that question, Boston University's Lauren Wise and her colleagues tracked women in their 30s for more than a decade to see if their fruit and vegetable consumption was tied to the chance they developed the non-cancerous growths.
"Many women have assumed that developing fibroids and developing fibroid symptoms is something that they can't do anything about," said Dr. Elizabeth Stewart, who studies fibroids at the Mayo Clinic in Rochester, Minnesota but wasn't involved in the new study.
"Although this doesn't prove if you change your diet you may be able to change your risk of fibroids, it appears that there is some association between diet and fibroids," she told Reuters Health. "Developing a more healthy diet rich in fruits and vegetables is good for overall health and may be good for fibroids."
The data came from the Black Women's Health Study, which starting in 1995 had participants report how often they ate a range of foods, from multiple times a day to less than once a month. Questionnaires sent every other year also asked women about any new medical diagnoses they had been given.
Based on those reports, 29 per cent of the 23,000 participants had a new case of uterine fibroids between 1997 and 2009.
Women who said they ate at least four servings of fruits and vegetables each day were 10 per cent less likely to get fibroids than those who ate less than one daily serving. When fruits and vegetables were analyzed separately, researchers found that eating more fruit was linked to a lower risk of fibroids -- but the same couldn't be said for veggies.
Participants who ate two or more servings of fruit daily, for instance, were 11 per cent less likely to say they'd developed fibroids than those who had less than two servings a week, according to findings published in the American Journal of Clinical Nutrition.
There was no link between how much vitamin C or E, folate or fiber women ate and their risk of fibroids, but the study suggested that getting more vitamin A from dairy products might also be associated with a lower fibroid risk.
At this point, the researchers can't be sure that the fruit, itself, protected women against fibroids.
Still, Wise told Reuters Health in an email that antioxidants in fruit may reduce fibroid risk, possibly by affecting the action of sex steroids like estrogen in the body.
"Increasing intake of fruit and vegetables is good for health in general," Wise said. "Our study suggests that uterine fibroids can now be added to the list of potential health outcomes for which increased fruit and vegetable intake might be beneficial."
Even if fruit does prevent against fibroids, any differences in consumption between black and white women wouldn't be enough to explain black women's extra fibroid risk -- and the fact that they often have more serious symptoms when they do get fibroids, researchers said.
"The genetics of fibroids probably varies by race, and there are other factors that influence fibroids that vary by race," said Stewart. "But nobody has been able to explain the huge gap in prevalence and symptomatology."