Long-Term Whole Grain Wheat and Rye Intake Reflected by Adipose Tissue Alkylresorcinols and Breast Cancer: A Case-Cohort Study.

Huaxing Wu,Anja Olsen,Cecilie Kyrø,Anne Tjønneland,Katja Boll,Kim Overvad,Rikard Landberg

doi:10.3390/nu11020465

Abstract

Whole grain rye (WGR) and whole grain wheat (WGW) have been suggested to protect against the development of breast cancer. In this study, we estimated long-term intake of WGR and WGW, using both a food frequency questionnaire (FFQ) and alkylresorcinol concentrations in adipose tissue biopsies, in relation to the risk of developing invasive breast cancer in a case-cohort study (n = 414 in the case group, n = 933 in the subcohort group) on the Danish “Diet, Cancer and Health” cohort. The median follow-up time of the subcohort was 5.3 years. Total WGR and WGW intake estimated with FFQ or reflected by total alkylresorcinol concentration in adipose tissue was not significantly associated with risk of breast cancer. However, after adjustment for total WGR and WGW intake, women in the highest quartile of relative WGR intake, reflected by the alkylresorcinol C17:0/C21:0 ratio, had a higher risk of overall breast cancer and estrogen-receptor-positive (ER+) breast cancer than women in the lowest quartile of relative WGR intake, while the risk of estrogen-receptor-negative (ER-) breast cancer incidence was unaffected. Similar results were obtained with the FFQ data. Based on these data, further investigation of the role of specific grain types in reducing or increasing breast cancer risk, and their overall impact on health, is warranted.

Highlights

Breast cancer is the most frequent cancer in women worldwide, with 1.68 million new cases reported in 2012 [1]
Estimated whole grain rye and wheat intake, total alkylresorcinol concentration in adipose tissue, age at baseline, waist-hip ratio, body mass index (BMI), parity, age at first period, age at menopause, age at first birth, years in school, smoking status, and exercise appeared similar for cases and subcohort members, whereas higher reported alcohol intake and alkylresorcinol C17:0/C21:0 ratio and slightly more frequent current use of menopausal hormones were found among cases
Total alkylresorcinol concentration in adipose tissue was significantly correlated with whole grain wheat intake (r = 0.13, P < 0.001), whole grain rye intake (r = 0.28, P < 0.001), and total whole grain rye and wheat intake (r = 0.31, P < 0.001)

Summary

Introduction

Breast cancer is the most frequent cancer in women worldwide, with 1.68 million new cases reported in 2012 [1]. Human intestinal bacteria metabolize plant lignans to enterodiol and enterolactone, compounds with estrogenic and anti-estrogenic activity that have been associated with a lower risk of breast cancer in some, but not all, observational studies [15,16,17,18]. Plausible mechanisms for this have been suggested, but inconsistent associations between whole grain intake and breast cancer have been reported in observational studies

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