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The Fibroids-Diet Connection

 

More than a decade ago, researchers identified a connection between a meat-heavy diet (specifically, the consumption of ham and beef) and uterine fibroids. The same study, published in the medical journal Obstetrics & Gynecology, produced evidence that diets heavy in green vegetables reduced the risk of developing fibroids. Since that time, numerous studies have sought to further explain the connection between diet and fibroid risk. Unfortunately, that research has yielded few answers, and the connection remains largely misunderstood and widely debated.

Foods Impacting Fibroid Growth

While no causal links have been established, there are clear themes emerging from study data. Multiple studies have correlated increased consumption of fruit, vegetables, and low-fat dairy products with reduced risk of developing fibroids. A study published in 2010 in the American Journal of Epidemiology was one such study. The research team of Wise et al. followed trends in the dietary intake of more than 22,000 premenopausal black women from the US Black Women’s Health Study over a 10-year period. Self-reported data from questionnaires gave the researchers insight into participants’ intake of dairy foods – including milk, cheese, yogurt, and ice cream – and nutritional components of dairy – like calcium, vitamin D, and butyric acid. The collected data revealed a connection between higher dairy consumption and a lowered risk of uterine fibroids. The researchers theorize that calcium and butyric acid (present in milk fat) inhibit the proliferation of cells that would otherwise form the benign pelvic tumors.

In a separate research effort, Wise et al. used the diet questionnaires collected from a cohort of participants in the Black Women’s Health Study to gather evidence regarding the link between fibroid risk and the consumption of fruits, vegetables, and carotenoids. In the December 2011 issue of American Journal of Clinical Nutrition, the researchers reported finding a reduced risk of uterine fibroids among the women with higher levels of fruit and retinol in their diets. These findings build upon those reported more than a decade ago by Chiaffarino and colleagues, who determined that a high intake of green vegetables has a protective effect against fibroids.

Margaret Wertheim, MS, RD, LDN, a Chicago-based dietitian, sees the same value in green vegetables. She advises her clients with fibroids to increase their intake of cruciferous vegetables like cabbage, broccoli, and kale. “This group of vegetables, in particular, contains indole-3-carbinol,” she explains, “which research has suggested may prevent estrogen-driven tumors due to its effect on estrogen metabolism.”

While research has drawn attention to the protective effects of foods like dairy consumption and green vegetables, it has also revealed a heightened risk of fibroids associated with the consumption of meat products. Women whose daily diets include meats like beef and ham are – according to the research – more likely to develop fibroids than women who consume a strictly vegetarian diet.

Some research, including a 2010 study by Di and colleagues, has suggested that certain phytoestrogens found in soybeans, called isoflavones, may inhibit the growth of estrogen-dependent uterine fibroids. Contradictory evidence was produced by Radin et al, however, when they examined the soy intake of a subpopulation from the aforementioned U.S. Black Women’s Health Study and found no connection between soy consumption and uterine fibroid risk.

Fibroid growth is fueled by estrogen. Thus, in theory, any chemicals or nutrients that affect the body’s estrogen levels will impact fibroids in some way. Growth hormones in non-organic beef and phytoestrogens in soy are simple examples, but other potentially problematic substances are those that indirectly impact the body’s hormonal balance. For example, Wertheim recommends that women with fibroids watch their caffeine and alcohol intake. Both caffeine and alcohol stress the liver, which can make the liver work less effectively at metabolizing estrogen in the body. “With fibroids,” she explains, “you want to support the health of the liver by getting rid of alcohol and caffeine so it may optimally metabolize circulating estrogen.”

Finally, the role of vitamin D in affecting fibroid growth has been a subject of recent interest. A study published in a 2011 issue of Fertility and Sterility reported that vitamin D inhibits the growth of cells involved in uterine fibroid growth. The data produced by the researcher team of Sharan et al. suggested that low levels of vitamin D may be a risk factor for their developing fibroids.

Diet Modification: Does It Help?

Though certain dietary connections may seem clear, the implications of dietary modification for treating existing fibroids certainly aren’t. Bala Bhagavath, MD, an endocrinologist at the Center for Reproduction & Infertility at Women & Infants Hospital in Rhode Island, explains the limitations of the existing data in a 2012 article from Today’s Dietitian. He points out that the studies that have been conducted are all observational in nature; no interventional studies have been conducted to determine the effectiveness of diet modification as a treatment strategy. “It’s not known if modification of diet in women with established uterine fibroids will result in resolution of these tumors,” he says. “Even if they do, the length of time this dietary modification has to be maintained has to be established. It’s possible that dietary modification may decrease the incidence of fibroids in women at high risk for developing them. However, even this question of prevention remains unanswered at this time.”

Based on what we know (and don’t know!) about the fibroids-diet connection, it’s unrealistic to expect that dietary changes alone can eliminate and/or prevent fibroids. However, the knowledge that has been uncovered regarding dietary risk factors can be useful in guiding nutritional strategies that will support a broader treatment protocol. Simply understanding the impact – direct or indirect – that certain vitamins and nutrients have on fibroid growth enables women with symptomatic fibroids to make better dietary choices, avoiding foods that could worsen their condition, and possibly enhancing the effectiveness of other medical treatments as a result.

 

SOURCES:

Stewart, E. “Uterine Fibroids”, New England Journal of Medicine. 2015; 372: 1646-55

Chiaffarino et al. “Diet and uterine myomas”, Obstetrics & Gynecology. 1999; 94(3): 395-398

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

Levy, B., “Modern management of uterine fibroids”, Acta Obstetricia et Gynecologica. April 2008; 87: 812-823

Wise, et al. “A prospective study of dairy intake and risk of uterine leiomyomata”, American Journal of Epidemiology. 2010; 171(2): 221-232

 

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Fibroids Are Not Color Blind

Over the years, researchers have examined the epidemiological connection between a wide variety of patient characteristics and the occurrence of uterine fibroids, seeking to identify risk factors. Age, weight, diet, geographic location, lifestyle factors like cigarette smoking, medical conditions, and history of childbirth have all been studied, and many have been correlated with fibroids in one way or another. But time after time, study after study, one characteristic has stood out as a major indicator of fibroid risk: race. And the conclusion that researchers have consistently reached is this: uterine fibroids (also known as leiomyomas) disproportionately affect women of color.

Certain, specific differences have been seen in the cases of black women: research shows that, in comparison to white women, black women tend to develop a larger number of fibroids and experience more fibroid-related symptoms. A study published in 2013 by the American Society for Reproductive Medicine reported that, “African-American women had substantially more fibroids” with an average of 9.9 fibroids compared to the Caucasian subjects’ average of 4.5 fibroids. Additionally, Weiss et al. conducted a multi-ethnic, multisite, longitudinal study of 3,302 women ages 42-52 and concluded that “previously diagnosed leiomyomas were presenting symptoms more frequently in African-American woman than Caucasian women (85% vs. 63%)”.

The racial disparity in fibroid occurrence isn’t fully understood. The research that exists mostly defines the relative risk of the condition in terms of black and white. Obviously, black and white women aren’t the only ones affected by uterine fibroids. While very little data exists on the differences in susceptibility and symptoms between other ethnicities, a 2011 study conducted by the U.S. Armed Forces identified the relative risk of fibroids for multiple ethnic groups. The study looked at the population of active military women who were diagnosed with fibroids between 2001 and 2010: 11,931 cases were recorded. The researchers concluded that, relative to the white, non-Hispanic population, the risk of fibroids was slightly higher (1.1 times) for Hispanics and Asians/Pacific Islanders, and slightly lower (.9 times) for American Indians/Alaskan Natives. By comparison, African American women were 4.4 times more likely to have the same diagnosis, and women in the ethnic category of “Other” had almost double (1.9 times) the incidence of fibroids. These findings are depicted in the graph below.

Fibroids--race_MSMRgraph

As of now, there are no clear answers to explain why symptoms and presentation of uterine fibroids are different in women of color. However, the connection between fibroids and race is certainly a topic of interest to researchers, physicians and fibroid patients alike, and one that continues to be the subject of medical research.

Sources:

  1. Schwartz, S.M. “Epidemiology of uterine leiomyomata”, Clinical Obstetrics & Gynecology. June 2001; Vol.44(2):316-26
  2. Moorman, P.G. et al. “Comparison of characteristics of fibroids in African American and white women undergoing premenopausal hysterectomy”, Fertility & Sterility, March 2013; Vol.99(3)768-776>
  3. Weiss, G. et al. “Racial differences in women who have a hysterectomy for benign conditions”, Women’s Health Issues, May-June 2009; Vol.19(3):202-10
  4. Eltoukhi, H.M. et al. “The health disparities of uterine fibroid tumors for African American women: a public health issue”, American Journal of Obstetrics & Gynecology, March 2014; Vol.210(3)
  5. “Uterine Fibroids, Active Component Females, U.S. Armed Forces, 2001-2010”, Medical Surveillance Monthly Report, December 2011; Vol.18(12):10-13

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