(P30-40-26) Effects of a Legume-Based Dietary Intervention on Insulin Resistance and Inflammatory Biomarkers

Objectives: We evaluated the effect of a 6-month high-fiber legume diet (HLD) on biomarkers of insulin resistance and inflammation.

Methods: This randomized control trial included 56 adults with overweight and obesity (64% females; mean age ± SD: 60.4 ± 7.6 years), with 29 randomized to HLD and 27 to a control weight-loss diet. Participants received pre-portioned, energy and macronutrient-matched meals aligned with their assigned diet, along with individualized nutrition education. Participants in HLD group consumed ~250 g/day of legumes (~1½ cups cooked), while the control group received comparable meals replaced by lean meats. Fasting glucose, fasting insulin, high-sensitivity C-reactive protein (hsCRP), and homeostatic model assessment of insulin resistance (HOMA-IR) were measured at baseline and 6 months. To evaluate biomarker changes, we fit linear mixed-effects models adjusted for age, sex, race, and baseline BMI.

Results: At baseline, mean biomarker levels were similar between groups: hsCRP was 4.5 mg/L in the control group and 2.9 mg/L in the legume group; fasting glucose was 100.8 mg/dL and 98.4 mg/dL; fasting insulin was 10.8 µU/mL and 12.7 µU/mL; and HOMA-IR was 2.8 and 3.2, respectively. After 6 months, biomarker levels improved in both diet groups. Participants on the legume diet experienced slightly larger average reductions in hsCRP (–0.8 mg/L), fasting insulin (–2.5 µU/mL), fasting glucose (–1.8 mg/dL), and HOMA-IR (–0.5), which were comparable to reductions in the control group (–0.7 mg/L, –1.7 µU/mL, –2.4 mg/dL, and –0.5, respectively). In adjusted mixed-effects the legume diet was not associated with significantly greater improvements than the control diet for hsCRP (β = –0.23, 95% CI –1.16, 0.71), fasting glucose (β = –0.96, 95% CI –6.49, 4.56), fasting insulin (β = –0.34, 95% CI –3.20, 2.52), or HOMA-IR (β = –0.02, 95% CI –1.03, 1.00).

Conclusions: Weight-loss diet and nutritional counseling may help adults living with obesity improve insulin resistance and inflammatory biomarkers.

Funding Sources: This work was supported by grants from the National Cancer Institute of the National Institutes of Health and Georgia Clinical and Translational Science Alliance.