Whether a woman gets it from beans, fruits, vegetables, or grains – dietary fiber has been found to lower a woman’s risk for breast cancer, studies have found.
Increased Fiber Intake Helps Prevent Breast Cancer
A comprehensive study published by Maryam Farvid and team from Harvard T.H. Chan School of Public Health in Boston studied data from 20 different trials involving millions of women. It revealed that a high total fiber consumption can lower risk of breast cancer by 8%, compared to low consumption of fiber. The study was published by the American Cancer Society in the journal Cancer.
The researchers compared fiber consumption and types of fiber intake, and its link to breast cancer incidence rates in 17 cohort trials, one clinical trial, and two nested case trials. Results have shown that those who consumed the most fiber tend to have an 8% reduced risk of cancer.
The team found that American women usually get 45% of their dietary fiber from cereals and whole grains. Veggies are the source of around 23% of fiber, and the rest are divided between beans, nuts, seeds, and fruits. However, the study found that it doesn’t matter where the dietary fiber came from.
The researchers also found that only soluble fiber, the kind that can be found in foods like nuts, cereals, fruits, veggies, oatmeal, beans, lentils, and peas, had a statistically significant association with reduced breast cancer incidence. Insoluble fiber is also found to reduce the risk but the effect wasn’t statistically significant.
The studies involved prospective trials, where a trial is set up and result are tabulated as time goes by. Prospective studies are known to have more validity and accuracy in results than retrospective studies that ask women what they ate in the past.
Besides the overall reduction in the risk of cancer, the review also found that the anti-cancer benefits of fiber can be applied to women of all ages. Postmenopausal and pre-menopausal women can also experience a significantly decreased risk of developing breast cancer by getting a high intake of fiber.
Most of the studies were concerning postmenopausal breast cancer, but five reports examined premenopausal cancer, the effect of fiber was more significant: an 18 percent reduced risk for women who consumed the most.
There are several possible mechanisms why taking more fiber reduces the risk of breast cancer, which includes increased levels of sex hormone-binding globulin, improved insulin sensitivity and blood glucose control, and improved intestinal microbiota.
A high fiber diet is also associated with increased intake of vitamins, minerals, and phytochemicals that can protect the body and help fight against cancer.
So, help prevent your body from developing cancers, try to consume all sources of fiber. Even if it’s only a modest risk reduction, adding different types of fiber to your diet offers many other health benefits to the body. The American Cancer Society’s recommended dietary guideline suggests higher consumption of whole grain, fruits, vegetables, and other high fiber food choices to prevent development of cancer.
How Fiber Affects Breast Cancer
Fiber-rich foods are found to contain compounds that can influence breast cancer growth and development. Here are some explanations as to how fiber influences breast cancer:
- Fiber increases frequency of bowel movements, which helps reduce breast cancer risk by increasing estrogen excretion. Circulating estrogen levels are a risk factor for breast cancer.
- High-fiber diets reduce the circulating C-reactive protein, which is an indicator of inflammation. Inflammation increases the risk of many diseases, including cancers.
- Fiber intake reduces weight gain. Being overweight and postmenopausal increases the risk of breast cancer for women.
- High fiber intake decreases serum cholesterol levels. Some evidences suggest that high cholesterol promotes breast cancer.
- Increased fiber intake – soluble fiber in particular – can improve blood sugar control and reduce excess insulin in persons with type 2 diabetes. Excess insulin in the blood, also known as hyperinsulinemia, increases risk of breast cancer and recurrence.
Natural Sources of Fiber
A healthy, fiber-rich diet is essential for the body, and having a decreased risk of developing breast cancer is just cherry on top. The following foods are excellent sources of soluble and insoluble fiber that is associated to reduced risk of breast cancer:
- Dry beans
- Brussel sprouts
- Bel peppers
- Brown rice