Too many starchy carbs seem to be associated with breast cancer recurrence. Researchers at the University of California, San Diego divided 2,651 breast cancer survivors into four groups based on their daily carbohydrate intake. Over the course of a year, the study revealed an average daily increase of 2.3 grams of carbohydrates among the women whose breast cancer recurred compared to an average decrease of 2.7 grams among the women whose cancer did not recur.
The researchers found that changes in starch consumption accounted for 48 percent of the differences in carbohydrate intake. Among the women whose cancer did not recur, starch intake dropped by 8.7 grams a day compared to a decline of only 4.1 grams a day among the women whose cancer did return. Overall, the rate of breast cancer recurrence over one year was 9.7 percent among women whose starch intake dropped the most compared to a 14.2 percent recurrence rate among those whose starch intake increased the most.
The investigators suggested one possible explanation for this effect: starchy foods boost insulin levels and elevated insulin levels have been associated with a higher risk of breast cancer.