FORCE’s eXamining the Relevance of Articles for Young Survivors (XRAYS) program is a reliable resource for breast cancer research-related news and information. XRAYS reviews new breast cancer research, provides plain-language summaries, and rates how the media covered the topic. XRAYS is funded by the CDC.
Breast cancer survivors
Women under 45
Women over 45
Men with breast cancer
Metastatic breast cancer
Triple negative breast cancer
BRCA mutation carriers
Her2+ breast cancer
Some researchers believe that dietary fiber may decrease breast cancer risk by lowering estrogen levels in the blood. However, many previous studies have failed to find a link between fiber consumption and lower breast cancer risk. The current study suggests that consuming high dietary fiber during adolescence and young adulthood may lower breast cancer risk, but more work needs to be done to confirm this finding. In the meantime, everyone is encouraged to eat a variety of high fiber foods for the many well-documented health benefits. (March 8, 2016)
The effect of a high-fiber diet on breast cancer risk for young adults.
Researchers think that eating a high-fiber diet may reduce breast cancer risk by reducing estrogen levels in the body.
This study indicates that eating dietary fiber during adolescence and early adulthood may reduce breast cancer risk. More research needs to be done to confirm this finding, because previous studies, which looked at fiber consumption in older women, do not agree with this finding.
Regardless of its effect on breast cancer risk, incorporating fiber into the diet benefits a healthy lifestyle. The American Cancer Society guidelines recommend eating foods that are high in fiber. The Mayo Clinic notes that a diet high in fiber maintains bowel health, lowers cholesterol levels, controls blood sugar levels and helps people to achieve and/or maintain a healthy weight.
Previous research found that dietary fiber does not affect breast cancer risk. However, most of these studies involved older women, and did not look at fiber consumption during adolescence or early adulthood, a critical time when exposure to factors that affect estrogen levels may affect breast cancer risk.
In March 2016, Maryam Farvid and colleagues from the Harvard T.H. Chan School of Public Health and other institutions published a paper in the journal Pediatrics that examined the relationship between dietary fiber intake during adolescence and young adulthood and breast cancer risk later in life.
Whether dietary fiber can modify breast cancer risk.
This study involved 90,534 premenopausal women between the ages of 27-44 who were part of the Nurses’ Health Study II cohort. To be a part of this study, the women could not have reported a previous cancer diagnosis (except non-melanoma skin cancer). The women answered questionnaires that asked about their diet from the point the study began, and were resurveyed every four years over a 20-year period.
This group of women was also asked to complete another questionnaire about their diet during high school; 47,355 women returned this questionnaire.
High-fiber foods also contain many other biologically active ingredients—researchers noted that they cannot exclude the possibility that some ingredients other than fiber contributed to lower breast cancer risk. Additionally, the study population was not a random sampling of women in the U.S.; all participants were registered nurses who are a part of the Nurses’ Health Study II cohort. All studies that look at these types of associations may be affected by other factors that researchers were unable to identify or control. The researchers in this study took into account many other factors that could affect breast cancer risk, but they were unable to definitively say that no other factors were involved.
This study suggests that consuming a diet that is high in fiber during adolescence and early adulthood may reduce breast cancer risk. However, more work needs to be done to confirm this finding. In the meantime, people should be sure to include dietary fiber in their diets regardless of the effect on breast cancer risk, as it is part of a healthy lifestyle.
Farvid MS, Eliassen H, Cho E, et al. “Dietary Fiber Intake in Young Adults and Breast Cancer Risk.” Pediatrics. 137 (3), March 2016.
Kushi, LH, Doyle, C, McCullough, M, et al., “American Cancer Society guidelines on nutrition and physical activity for cancer prevention,” CA: A Cancer Journal for Clinicians. 62 (1), p. 30-67, January/February 2012.
Mayo Clinic Staff. “Dietary fiber: Essential for a healthy diet.”