One-year nutrition counselling in the context of a Mediterranean diet reduced the dietary inflammatory index in women with breast cancer: a role for the dietary glycemic index†

Background: the Mediterranean diet, the low dietary glycemic index (GI) and the dietary inflammation index (DII®) have been associated with lower risk of breast cancer (BC) incidence and mortality. Objective: to investigate whether one-year nutrition counselling in the context of a Mediterranean diet, with or without low-GI carbohydrates counselling, may influence the DII in women with BC. Methods: data were obtained from participants of DEDiCa trial randomized to a Mediterranean diet (MD, n = 112) or a Mediterranean diet with low-GI carbohydrates (MDLGI, n = 111). The diet-derived DII and GI were calculated from 7-day food records while Mediterranean diet adherence from PREDIMED questionnaire. Differences between study arms were evaluated through Fisher's exact test or Mann-Whitney test and associations with multivariable regression analyses. Results: Mediterranean diet adherence significantly increased by 15% in MD and 20% in MDLGI with no difference between arms (p < 0.326). Dietary GI significantly decreased from 55.5 to 52.4 in MD and 55.1 to 47.6 in MDLGI with significant difference between arms (p < 0.001). DII significantly decreased by 28% in MD and 49% in MDLGI with no difference between arms (p < 0.360). Adjusting for energy intake (E-DII) did not change the results. Higher Mediterranean diet adherence and lower dietary GI independently contributed to DII lowering.