The effect of different nutritional interventions on insulin resistance in women with breast cancer

Preventing breast cancer recurrence is a public health challenge. Insulin resistance is a prognostic factor in women who have survived breast cancer. Although the Mediterranean diet (MedDiet) has been associated with a lower risk of insulin resistance, few studies have been conducted in women with breast cancer. The primary objective of this study was to evaluate the effect of a MedDiet-based intervention compared to a low-fat diet (LFD) on HOMA-IR and HOMA-B values after 2 years of follow-up in women beginning treatment after a breast cancer diagnosis. This study is part of the LifeBreast trial, in which 366 women with breast cancer and a mean age of 54 years (SD 9 years) were included. Participants were randomized in a 1:1 ratio to the intervention group receiving MedDiet and the control group receiving LFD. Nutritional education in both groups lasted 2 years. After exclusions, 314 women were included in this analysis. The dependent variables were HOMA-IR (primary outcome) and HOMA-B. For each of these variables, mixed linear models were used to assess changes between groups over time. We found a significant change in HOMA-IR over the 2-year follow-up between both intervention groups. Specifically, we observed a reduction in HOMA-IR of -0.11 (95% CI -0.35, 0.12) in participants in the MedDiet group and an increase of + 0.22 (95% CI -0.02, 0.46) in the LFD group (p group xtime=0.046). Regarding HOMA-B, the change was +28.7 (95% CI 7.3, 44.2) in participants in the MedDiet group and +35.1 (95% CI 19.3, 50.9) in participants in the LFD group (p groupxtime=0.384). In conclusion, a MedDiet intervention achieved a greater reduction in HOMA-IR compared to the LFD intervention. Further research in clinical settings is warranted.

Key messages

• We evaluated a Mediterranean diet intervention vs a low-fat diet intervention among women with breast cancer on HOMA-IR and HOMA-B over 2 years.

• A Mediterranen diet intervention achieved a greater reduction in HOMA-IR compared to the low-fat intervention.