Breast Cancer Risk and Adolescent Diet
The evidence that adolescent diet may affect the risk of breast cancer derives from several lines of evidence. Rates of breast cancer among Asian immigrants to the United States do not approach those of US white women until the second or third generation, suggesting that exposures during childhood and adolescence are important in establishing a higher risk of breast cancer. (J Natl Cancer Inst 1973, 51:1479-1483, J Natl Cancer Inst 1993, 85:1819-1827).
Norwegian women who were adolescents during World War II, when average caloric intake decreased by 22%, have a reduced incidence of breast cancer, suggesting that energy restriction might affect risk. (Cancer Causes Control 1996, 7:507-512).
A nested case-control study was conducted among participants in the Nurses’ Health Study who completed a 24-item questionnaire about diet during high school. There were 843 eligible cases diagnosed [with breast cancer] between onset of study (1976) and before the return of the high school diet questionnaire (1986), who were matched 10:1 with controls on the basis of age.
Participants who had completed the high school diet assessment section of the 1986 follow-up questionnaire and who also had reported current diet in 1980 were eligible for the study.
Breast cancer cases reported lower vitamin A intake and higher alcohol intake in 1980 than did controls.
Increased consumption of eggs was inversely associated with risk of breast cancer. Eggs are rich sources of essential amino acids, minerals and vitamins. For instance, one egg contains 11.5% of the recommended daily allowance for folate and 6.5% of that for vitamin D.
Conversely, increased consumption of butter was associated with a slight increase in risk. Neither animal fat, total fat, nor unsaturated fat was associated with increased risk on nutrient analysis; however, another nutrient in butter might confer increased risk, or the consumption of butter might be a proxy for another risk factor.
When specific nutrients were examined, increased consumption of both vegetable fat and dietary fiber was associated with a decreased risk of breast cancer. Fiber might affect the risk of breast cancer by decreasing estrogen levels; fiber binds estrogen excreted into the gastrointestinal tract and reduces enterohepatic circulation. (J Steroid Biochem Mol Biol 1991, 39:193-202, J Steroid Biochem Mol Biol 1991, 38:621-628).
In addition, higher dietary fiber intake has been associated with higher plasma levels of sex-hormone-binding globulin, which can reduce the bioavailability of estrogens. (Cancer 1994, 74:1125-1131).
The potential mechanism of a protective effect of vegetable fat is more speculative: vegetable fat is a composite of multiple forms of fatty acids, some of which have been proposed to increase risk - such as C18:2n-6, whereas other specific fatty acids have been proposed to decrease risk - such as C18:1, the primary fatty acid in olive oil. (Am J Clin Nutr 1997, 66(Suppl):1557S-1563S).
More detail on the type and composition of the vegetable oil used is necessary to pursue this relation with greater precision.
References
Adolescent diet and risk of breast cancer. Frazier AL, Ryan CT, Rockett H, Willett WC, Colditz GA. Breast Cancer Res 2003, 5:R59-R64 (21 February 2003). This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. http://breast-cancer-research.com/content/5/3/R59
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Tretli S, Gaard M: Lifestyle changes during adolescence and risk of breast cancer: an ecologic study of the effect of World War II in Norway. Cancer Causes Control 1996, 7:507-512.
Arts CJ, de Bie AT, van den Berg H, van't Veer P, Bunnik GS, Thijssen JH: Influence of wheat bran on NMU-induced mammary tumor development, plasma estrogen levels and estrogen excretion in female rats. J Steroid Biochem Mol Biol 1991, 39:193-202.
Arts CJ, Govers CA, van den Berg H, Wolters MG, van Leeuwen P, Thijssen JH: In vitro binding of estrogens by dietary fiber and the in vivo apparent digestibility tested in pigs. J Steroid Biochem Mol Biol 1991, 38:621-628.
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Willett WC: Specific fatty acids and risks of breast and prostate cancer: dietary intake. Am J Clin Nutr 1997, 66(Suppl):1557S-1563S.
