Even with the recent emphasis placed on early detection and mammograms, breast cancer statistics remain shockingly high. According to the Centers for Disease Control and Prevention (CDC), in 2007, nearly 203,000 women in the United States were diagnosed with breast cancer, and more than 40,000 women died of the disease in the same year.
Thanks to groups like Susan G. Komen Breast Cancer Foundation and even Avon and their walk for breast cancer, this disease continues to stay in the spotlight as advocates push for more research into prevention, treatment, and a cure.
From these efforts, we’ve discovered that poor diet is a huge risk factor for breast cancer. Additionally, it’s been shown that high fiber intake can help to lower your risk. But what about the exact type of fiber? Does it make a difference? A recent study from Finland set out to determine exactly that.1
Fiber and Cancer
It is widely known and accepted that eating fiber (namely whole grains) helps to reduce your risk of virtually every form of cancer, save for thyroid cancer.2 But how does it do that? In the case of breast cancer, it comes down to estrogen.
During estrogen metabolism, the most potent form of estrogen (estradiol) is converted into estrone. Estrone then becomes either 2-hydroxyestrone, a “good” estrone metabolite, or 16-alpha-hydroxyestrone, a “bad” estrogen metabolite.
This “bad” estrogen metabolite has been deemed carcinogenic and likely plays a role in estrogen-dependent breast cancer. So the trick is to either block the conversion of estrone into 16-alpha-hydroxyestrone, or to get the metabolite out of the body before it can do any damage.
That’s where fiber comes in. It’s no secret that when you eat more fiber, you go to the bathroom more frequently. This is a good thing for a number of reasons, but particularly as it relates to breast cancer. Fiber reduces estrogen activity by binding to these free estrogen metabolites and escorting them out of the body when you go to the bathroom. More fiber means more bathroom trips, less dangerous estrogen in your body and, therefore, lower risk for breast cancer.
Does Type Matter?
Given the clear benefit of fiber for cancer prevention, a researcher from the University of Helsinki in Finland wondered if products made from whole grain rye flour specifically could reduce breast cancer risk.1
Rye foods are very high in fiber, especially insoluble fiber. They are also rich in lignans fiber-related compounds that bind to estrogen and other hormones, increasing their elimination from the body. In fact, when it comes to grains used to make bread, rye has the highest concentration of lignans.
This all bodes well for rye. Its rich stores of both fiber and lignans clearly show that it can help reduce breast cancer risk. And this is supported by other studies in which high intake of rye products was associated with a low risk of breast cancer.3,4
So, does this mean that rye is superior to other forms of whole grains? No.
Despite vigorous research and indications that, in addition to fiber and lignans, rye also contains powerful antioxidants and other anti-carcinogenic nutrients, there is nothing concrete that shows rye to be better than other whole grains at reducing breast cancer risk.
Fiber — and Lots of It — is Key
While the study couldn’t show if one grain or another was better at reducing your risk for breast cancer, it did prove that fiber and lignans do. Therefore, if you want to lower your chances of developing breast cancer, fiber is the answer.
Some of the best food sources of fiber include:
- Whole grains such as rye, barley, whole wheat and oatmeal
- Brown rice
- Fruits such as apricots, prunes, and apples
- Vegetables, especially broccoli, cauliflower, Brussels sprout and spinach
On the supplement side, you can use oat bran and/or psyllium (1–2 tablespoons per day) mixed into water, juice, or even added to a fruit smoothie.
No matter how you get your fiber, just get it. Every day.
1 Adlercreutz, H. Can rye intake decrease risk of human breast cancer? Food & Nutrition Research. 2010;54:5231.
2 Chatenoud, L, et al. Whole grain food intake and cancer risk. Int J Cancer. 1998;77:24-8.
3 Pietinen, P, et al. Serum enterolactone and risk of breast cancer: a case-control study in eastern Finland. Cancer Epidem Biomark Prev. 2001; 70: 339-44.
4 Stumpf, K. Serum enterolactone as a biological marker and in breast cancer: from laboratory to epidemiological studies. Helsinki: University of Helsinki; 2004. p. 157.