Fiber May Cut Risk of Kidney Cancer
Eating plenty of fiber and fiber-rich foods may reduce the risk of kidney cancer among those at a healthy weight, suggests a large new study of almost half a million people. The study was published in The American Journal of Clinical Nutrition.
AICR’s expert report and its updates concluded that excess body fat increases kidney cancer risk; the limited evidence linking diet to risk has produced inconsistent findings. The new study investigated renal cell carcinoma, the most common type of kidney cancer.
The study used data from the NIH-AARP Diet and Health Study: Participants filled out answers about their diet and lifestyle when they entered the study in 1995-96. The researchers divided participants into five groups, depending upon how much fiber they consumed. After an average of nine years, participants who consumed the most dietary fiber had a 15 to 20 percent lower risk of kidney cancer compared to those who ate the least. When the study analyzed fiber intake by foods, legumes independently linked to lower risk. Comparing the highest to lowest conusming groups, the study also found that whole grains along with the cruciferous vegetables cauliflower, broccoli and Brussels sprouts also linked to reduced risk of kidney cancer.
This association held when the researchers adjusted for sex, race, alcohol intake, and a history of hypertension. But when the study adjusted for weight, they found a difference: there was link between fiber intake and lower risk of kidney cancer among those who were of normal weight and overweight (BMI less than 30), but not among people who were obese (a BMI over 30 or higher). There was also no association seen among participants with a history of diabetes.
It’s possible that fiber plays a role on cancer risk through its positive effect on obesity, insulin-related factors and blood glucose, note the authors.
Source: Carrie R Daniel et al. “Intake of fiber and fiber-rich plant foods is associated with a lower risk of renal cell carcinoma in a large US cohort.” Am J Clin Nutr May 2013