Teenage girls and young women who eat a lot of foods high in fiber, such as fruits and vegetables, may have a lower risk of breast cancer later in life, a new study suggests.
The researchers found that the women who consumed high amounts of fiber during early adulthood had a 12 to 19 percent lower risk of developing breast cancer over the 20-year study, compared with the women who consumed very little fiber in early adulthood.
And the women who consumed high amounts of fiber during their teenage years had a 24 percent lower risk of developing breast cancer before menopause, compared with those who consumed little fiber as teens.
"This study reminds us the role of early-life diet on health in later life," said lead study author Maryam Farvid, a scientist at the Harvard T.H. Chan School of Public Health. "Women are doing themselves a huge favor in terms of breast cancer prevention if they increase the amount of dietary fiber intake earlier in life rather than later."
In the study, the researchers looked at data from more than 90,500 women ages 27 to 44 about what they normally ate, and followed them for 20 years. At one point during the study, they also asked the women about their diets during high school. [6 Things Women Can Do to Lower Breast Cancer Risk]
During the course of the study, 2,833 of the women were diagnosed with breast cancer.
The researchers found that the more fiber the women consumed, the lower their risk of cancer was.
The results showed that "each additional 10 grams of fiber intake per day — for example, about one apple and two slices of whole wheat bread, or about half a cup of whole grain pasta with half a cup of cooked kidney beans — during adolescence reduces the risk of breast cancer by 14 percent," Farvid said.
Therefore, the new findings suggest that "choosing a high-fiber diet to obtain the recommended 25 to 30 grams of fiber daily in early life may substantially reduce the risk of breast cancer in midlife for women," she told Live Science.
The study found an association, and not a cause-and-effect relationship, between eating fiber and having a lower risk of breast cancer, and it's not clear what mechanism might link the two. But the researchers said they suspect that fiber may help to reduce high levels of estrogen in the blood, which have been linked with the development of breast cancer.
"From many other studies, we know that breast tissue is particularly influenced by carcinogens and anti-carcinogens during childhood and adolescence," study co-author Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, said in a statement. "We now have evidence that what we feed our children during this period of life is also an important factor in future cancer risk."
The new study was published today (Feb. 1) in the journal Pediatrics.