Insulinaemic potential of diet linked to colorectal cancer risk
A recent study suggests that the influence of dietary intake on the development of colorectal cancer is partly caused by dietary insulinaemic potential.
Associations between hyperinsulinaemic diets and colorectal cancer risk were assessed using an empirical dietary index for hyperinsulinaemia (EDIH), a food-based index that characterizes dietary insulinaemic potential based on circulating C-peptide concentrations.
Using food-frequency questionnaires, the investigators evaluated diet in 46,210 men (Health Professionals Follow-Up Study, 1986–2012) and 74,191 women (Nurses’ Health Study, 1984–2012) to calculate EDIH scores.
A total of 2,683 incident colorectal cancer cases were identified over 26 years of follow-up. Comparing participants in the highest vs those in the lower quintiles, higher EDIH scores in men, women, and both men and women were associated with 33 percent (hazard ratio [HR], 1.33; 95 percent CI, 1.11–1.61; p=0.0005), 22 percent (HR, 1.22; 1.03–1.45; p=0.01) and 26 percent (pooled HR, 1.26; 1.2–1.42; p<0.0001) higher risk of developing colorectal cancer, respectively.
While such associations were limited to the distal colon and rectum in men and to the distal and proximal colon in women, combined risk estimates remained significant for all anatomic locations except for the rectum.
Comparing participants in extreme EDIH quintiles, no significant association was observed for proximal colon cancer in men (HR, 1.15; 0.84–1.57; p=0.32). However, there was an increased risk for distal colon (HR, 1.63; 1.14–2.32; p=0.002) and rectal (HR, 1.63; 1.09–2.44; p=0.01) cancer. The risk in women was heightened for proximal (HR, 1.28; 1.00–1.63; p=0.03) and distal (HR, 1.46; 1.05–2.03; p=0.03) colon cancer but not for rectal cancer (HR, 0.88; 0.60–1.29; p=0.61).
“Insulin response may be important in colorectal cancer development. Diet modulates insulin response and may be a modifiable factor in colorectal cancer prevention,” the investigators noted.