Association between fruit and vegetable intake and metabolic health status, serum BDNF and adropin levels in Middle Eastern adults: a cross-sectional study

The connection between fruit and vegetable consumption and metabolic disorders remains controversial. This study aimed to investigate the association between fruit and vegetable intake and metabolic health, serum adropin and brain-derived neurotrophic factor (BDNF) in Iranian adults. This cross-sectional study included 527 adults (20–65 years), selected via multistage cluster random sampling. Dietary intake was assessed using a validated food frequency questionnaire. Blood pressure was measured, along with fasting serum triglycerides, HDL-cholesterol, glucose, insulin, hs-CRP, adropin, and BDNF. Participants with ≥ 2 of the following were classified as metabolically unhealthy: elevated fasting glucose, low HDL-cholesterol, elevated triglycerides, elevated blood pressure, insulin resistance, or elevated hs-CRP. The prevalence of metabolic unhealthy phenotype (MU) among participants was 42.5%. After controlling for potential confounders, individuals in the third tertile of fruits consumption had a lower odds of 68% (OR = 0.32; 95%CI: 0.15–0.68), and individuals in the third tertile of combined fruits and vegetables consumption had a lower odds of 57% (OR = 0.43; 95%CI: 0.20–0.94) for MU compared to those in the first tertile. Individuals in the third tertile of fruits and vegetables consumption showed a lower odds of 67% (OR = 0.33; 95%CI: 0.15–0.71) for hypertriglyceridemia and 78% (OR = 0.22; 95%CI: 0.06–0.77) for high hs-CRP. Higher fruit, vegetable, and combined fruit and vegetable consumption was associated with lower odds of having low BDNF levels, although this association did not reach statistical significance. Those in the top tertile of fruit and vegetable consumption had higher adropin levels, but not significantly. Fruits and combined fruits and vegetables consumption was associated with a reduction in odds of MU in Iranian adults, especially in normal weight individuals. Among MU components, higher fruits and combined fruits and vegetables consumption was associated with a decrease in likelihood of hypertriglyceridemia and chronic inflammation. Serum BDNF or adropin was not linked to fruits and vegetables consumption. These associations should be confirmed by prospective studies.