The association between aromatic amino acids consumption and the severity of pemphigus vulgaris: a cross-sectional study

Evidence on the association between aromatic amino acids consumption and the severity of pemphigus vulgaris (PV) is scarce. This cross-sectional study aimed to investigate the relationship between aromatic amino acids consumption and the severity of PV in Iranian population. In this hospital-based cross-sectional study, a total of 138 PV cases were studied, of which 108 had pemphigus disease area index PDAI < 15 (mild disease activity), and 30 had PDAI > 15 (moderate to severe disease). Dietary intakes of participants were assessed using a valid 168-item food frequency questionnaire (FFQ). The aromatic amino acids consumptions were obtained using the updated version of Nutritionist IV software, that was adjusted for Iranian foods. We found no significant association between dietary intakes of tryptophan with severity of PV in crude and adjusted models. The same trend was seen for dietary intake of tyrosine and phenyl-alanine in crude model. However, after adjusting for age, sex, disease duration, Corticosteroid use, protein, BMI and energy intake, we found that individuals in the highest quartile of tyrosine consumption compared with lowest (OR: 9.75; 95% CI: 1.14-83.27; P trend: 0.044) had higher severity for PV. Additionally, higher phenylalanine intake was associated with greater severity of pemphigus vulgaris in a continuous linear model, after adjusting for age, sex, disease duration, corticosteroid use, protein intake, BMI, energy intake, and aromatic amino acid intake (OR: 1.007; 95% CI: 1.001-1.013; P :0.028). Thus, the evidence of our study suggests that high consumption of tyrosine and phenyl-alanine is associated with increased disease severity. Prospective cohort studies are needed to confirm these findings.