Starch Intake May Influence Risk for Breast Cancer Recurrence

University of California/San Diego (UCSD; California, USA) researchers have linked increased starch intake to a greater risk for breast cancer recurrence. Jennifer A. Emond and colleagues conducted a subset analysis of 2,651 women who participated in the Women’s Healthy Eating and Living (WHEL) Dietary Intervention Trial, a plant-based intervention trial that enrolled about 3,088 survivors of breast cancer. WHEL researchers studied breast cancer recurrence and followed the participants for an average of seven years.   The subset analysis involved an examination of how changes in carbohydrate intake influenced breast cancer recurrence. The team obtained carbohydrate intake information from multiple 24-hour dietary recalls at baseline and at one year. In an annual phone interview, participants reported everything they had eaten during the last 24 hours.  At baseline, carbohydrate intake was 233 grams per day. Results showed that women whose cancer recurred had a mean increase in carbohydrate intake of 2.3 grams per day during the first year, while women whose cancer did not recur reported a mean decrease of 2.7 grams per day during the first year.   Starches were particularly important, as changes in starch intake accounted for 48% of the change in carbohydrate intake. Mean change in starch intake during the first year was –4.1 grams per day among women whose cancer recurred vs. –8.7 grams per day among women whose cancer did not recur.   When change in starch intake during one year was grouped into quartiles of change, the rate of an additional breast cancer event was 9.7% among women who decreased their starch intake the most during one year, compared with an event rate of 14.2% among women who increased their starch intake the most during one year. After stratifying patients by tumor grade, the team found that the increased risk was limited to women with lower-grade tumors.  Explaining that: “Breast tumors over express insulin-like-growth-factor receptors (IGF-IR), and levels of expression may be inversely related to tumor grade,” the study authors conclude that: “Dietary factors, particularly carbohydrate intake, may stimulate activation of IGF-1R and affect prognosis.  Dietary modifications targeting starch intake warrant further investigation as a preventive measure against breast cancer recurrence.”