Tree Nuts or Peanuts for Breast Cancer Prevention?

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The Black Women’s Health Study, which highlighted collards and carrots, was out of Boston University. Across the Charles River, the Harvard Nurses’ Health Study also tried to determine which plants were particularly protective in reducing breast cancer risk, and they identified nuts. 

“The intake of fiber and nuts during adolescence and incidence of proliferative benign breast disease”—such as fibrocystic breast disease; fibroadenomas; noncancerous breast lumps—but, is considered a marker for increased breast cancer risk. Depending on what biopsies show, it could indicate anywhere from 30% to 1,300% greater risk of going on to develop cancer.

Breast cancer can take decades to develop, so they wanted to start early, asking women what their diets were like back in high school. Now in adults, it’s clear, as you can see in this 2012 review: the more fiber you get in your diet, the lower your risk of breast cancer. And, same thing, apparently, when you’re younger. Women who had the most fiber intake during adolescence have a 25% lower risk of this potentially precancerous breast disease.

But, there’s fiber in fruits, vegetables, beans, whole grains, nuts, seeds—all plant foods. Did any class of plant foods stick out? Nuts were found to be particularly protective. Two servings a week was associated with a 36% lower risk.

But, that raises the question, which type of nuts? Like peanut butter and jelly sandwiches? Or, do you have to eat true nuts, like almonds, pecans, walnuts, that sort of thing? Just tree nuts, or peanuts as well? And the answer is: both.

Compared to those who rarely ate nuts, those eating just one or two handfuls a week during high school appeared to drop risk around 30%. “In summary, [their] study observed significant inverse associations between adolescent dietary intake of fiber and nuts and risk of proliferative benign breast disease. Our results provide supportive evidence of the important role of dietary exposures during a unique period in a woman’s life in the earlier stage of breast carcinogenesis [the early stage of breast cancer development]. These findings, if corroborated, may suggest a viable means for breast cancer prevention.”

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• Su X, Tamimi RM, Collins LC, Baer HJ, Cho E, Sampson L, Willett WC, Schnitt SJ, Connolly JL, Rosner BA, Colditz GA. Intake of fiber and nuts during adolescence and incidence of proliferative benign breast disease. Cancer Causes Control. 2010 Jul;21(7):1033-46.
• Boggs DA, Palmer JR, Wise LA, Spiegelman D, Stampfer MJ, Adams-Campbell LL, Rosenberg L. Fruit and vegetable intake in relation to risk of breast cancer in the Black Women's Health Study. Am J Epidemiol. 2010 Dec 1;172(11):1268-79.
• Aune D, Chan DS, Greenwood DC, Vieira AR, Rosenblatt DA, Vieira R, Norat T. Dietary fiber and breast cancer risk: a systematic review and meta-analysis of prospective studies. Ann Oncol. 2012 Jun;23(6):1394-402.

Images thanks to s58y and Ebelien via flickr

• adolescence
• almonds
• beans
• breast cancer
• cancer
• dietary guidelines
• fiber
• fibrocystic breast disease
• fruit
• grains
• Harvard
• Harvard Nurses' Health Study
• nuts
• peanut butter
• pecans
• seeds
• vegetables
• walnuts
• women's health