Exploring The Connection Between Fibroids And Obesity
The relationship between weight and uterine fibroids (also known as leiomyomas) is a complex one. However, while it is not fully understood, a link between obesity – which is typically defined by a Body Mass Index (BMI) ≥24 – and fibroid risk has been identified in multiple research studies. In fact, data suggest that obese women have two to three times the risk of developing fibroids than women of average weight.
Racial Disparities In The Impact of Obesity
Some research suggests that the relationship between BMI and fibroid risk differs between black women and white women. One study produced evidence that premenopausal black women may have higher ovarian hormone levels than white women (Woods et al., 1996). Another revealed that in black women, estradiol levels decrease as BMI increases in black women, whereas this was not the case for white women (Manson et al., 2001).
The Black Women’s Health Study, an ongoing prospective cohort study in the U.S. that was initiated in 1995, found the prevalence of obesity (BMI ≥30 kg/m2) to be nearly twice as high in black women as in white women. The incidence of uterine fibroids is also significantly greater in black women than white women, and the researchers involved concluded that this was not a coincidence: they hypothesized that a connection with the weight factor could partially explain the disparity in the disease burden. Looking more deeply at the results of the cohort study, the research team of Wise et al. noted that “weight gain was positively associated with risk among parous women (those who have given birth) only”.
Understanding the Hormone Connection
To understand the role that weight plays in fibroid development, one must start by looking at the common denominator: hormones. Ovarian hormones, particularly estrogen, play a key role in the development of fibroids. Obesity has been tied to hormonal and metabolic changes in women of reproductive age, included altered estrogen metabolism.
In a May 2012 article for Today’s Dietitian, Krystene DiPaola, MD, a reproductive endocrinologist and infertility specialist at the University of Cincinnati Academic Health Center, explains, “We do know that fibroids respond to estrogen, and that estrogen isn’t produced only in the ovaries but also in peripheral fat in the form of estrone,” she explains. “The estrone can, in higher doses such as in overweight women, affect fibroid growth and cause them to be more symptomatic.”
Does Diet Make a Difference?
The question then becomes, is it possible for an obese woman to minimize the occurrence or recurrence of her fibroids by losing weight? Unfortunately, research has not yet yielded a definitive answer to this question. However, some study data suggest that diet modification – and particularly the weight loss that may result – can make a difference in the presentation of fibroids. Because hormones are the driving force behind fibroid development, dietary choices that promote hormonal balance can potentially impact the development of fibroids and the severity of their associated symptoms.
DiPaola believes any nutritional modification that may lower peripheral fat stores, and therefore reduce estrogen production from those fat stores, only helps women with symptomatic fibroids. “In terms of my personal opinion,” DiPaola says, “the dietary component towards the treatment of fibroids can do nothing but help and may augment the traditional therapies to treat this condition.”
>> SEE ALSO: The Fibroids-Diet Connection
Takeda, T. et al. “Relationship Between Metabolic Syndrome and Uterine Leiomyomas: A Case-Control Study”, Gynecologic and Obstetric Investigation. July 2008; 66:14–17
Woods, MN. et al. “Hormone levels during dietary changes in premenopausal African-American women”,
Journal of the National Cancer Institute. Oct 1996; 88(19): 1369-74
Manson, JM. et al. “Racial differences in sex hormone levels in women approaching the transition to menopause”, Fertility and Sterility. Feb 2001; 75(2): 297-304
Wise, L. et al. “Influence of Body Size and Body Fat Distribution on Risk of Uterine Leiomyomata in U.S. Black Women”, Epidemiology. May 2005; 16(3): 346-354
Tempest, M. “Uterine Fibroids and Nutrition — Studies Suggest Healthful Dietary Modifications May Cut Risk and Ease Symptoms”, Today’s Dietitian. May 2012; 14(5): 40 http://www.todaysdietitian.com/newarchives/050112p40.shtml#sthash.tuDCxUd2.dpuf