A small Finnish study has reported that breast cancer survivors tend to have lower levels of biomarkers of whole rye and whole wheat consumption than women without a breast cancer history. Intake of fiber from grains has been proposed to reduce breast cancer risk by influencing the circulation of estrogens. Rye bread and other rye grain products are staple foods in Finland. Both rye and wheat bran contain alkylresorcinols and these compounds have been shown to be valid biomarkers of whole rye and whole wheat consumption. In the study, alkylresorcinol metabolites were used as potential biomarkers of breast cancer risk. The study included 20 vegetarians, 20 non-vegetarians, and 16 breast cancer survivors (6 to 12 months after breast cancer surgery). The women were assessed on two occasions six months apart.

Rye and wheat fiber intake, as well as blood and urine levels of alkylresorcinol metabolites, all were found to be significantly lower in the breast cancer survivors compared to the vegetarian and non-vegetarian groups. The authors conclude that whole-grain rye and wheat fiber intake is low in breast cancer subjects, findings which need to be confirmed in larger studies.