Habitual intake of dietary L-arginine in relation to risk of type 2 diabetes: a prospective study.

Background: There are insufficient data in case of the potential association of habitual dietary L-arginine and the risk of type 2 diabetes mellitus (T2DM) incidence. Here we aimed to examine the potential effect of dietary L-arginine on the T2DM incidence.
Methods: For this cohort study, 2139 T2DM-free adults from the participations of Tehran Lipid and Glucose Study (TLGS) were recruited. Follow up period was approximately 5.8 years. Daily intakes of protein and L-arginine were estimated using a validated food frequency questionnaire with 168 food item. Hazard Ratios (HRs) and 95% confidence intervals (CIs), adjusted for sex, age, smoking, diabetes risk score, physical activity levels, and total energy intakes as well as carbohydrate, fiber, fats and lysine, were calculated for L-arginine as both absolute intake and its ratio from total protein.
Results: Mean (±SD) age of the participants was 38.9 (±12.6) years and 54.6% were women. Mean (±SD) intake of dietary protein and L-arginine was 77.2 (±22.4) and 4.05 (±1.50) g/d, respectively. An increased risk of T2DM (HR = 2.71, 95% CI = 1.20-6.09) was observed among participants with higher intakes of L-arginine (median intake of > 5.4 vs. 2.69 g/d). Total protein intake and the ratio of L-arginine to total protein intakes were not related to incidence of T2DM in both crude and adjusted models.
Conclusion: We found that higher dietary L-arginine levels may increase risk of T2DM and it may have an independent role in T2DM development.