The association between healthy eating index and serum antioxidant indices in patients with different degrees of cataract compared to healthy subjects: a case-control study

Purpose Studies conducted on association between diet and cataract, found conflicting results. This paper aims to investigate the association between healthy eating index (HEI) and serum antioxidant and oxidant indices in patients with different degrees of cataract compared to the healthy subjects. Design/methodology/approach Ninety volunteers (aged > 50 years) were divided into the cataract (n= 45) and healthy control (n= 45) groups in this case-control study. Anthropometric variables, HEI score, serum total oxidant capacity (TOC) and total antioxidant capacity (TAC), blood pressure, physical activity and stress measurements were done for all participants. Findings There was a significant difference in stress level between subgroup of first-degree cataract and healthy controls (16.6 +/- 2.3 vs 42.5 +/- 29.0,p< 0.001) as well as third-degree cataract (16.6 +/- 2.3 vs 75.2 +/- 22.6,p< 0.001). Serum TAC was significantly higher in healthy people compared to the first-degree (1.2 +/- 0.2 vs 1 +/- 0.2,p= 0.002) and third-degree cataract patients (1.2 +/- 0.2 vs 1.0 +/- 0.2,p= 0.013). Also, serum TOC was significantly lower in healthy controls compared to the first-degree (8.2 +/- 1.1 vs 9.2 +/- 1.0,p= 0.006) and third-degree cataract patients (8.2 +/- 1.1 vs 9.1 +/- 1.2,p= 0.015). There was a significant direct correlation between moderation (r= 0.61,p= 0.019) and total score of HEI (r= 0.57,p= 0.031) with serum TAC only in the first-degree cataract patients. Also there was a significant negative correlation between moderation score of HEI with serum TOC in the first-degree cataract patients (r= -0.60,p= 0.025), and there was a significant negative correlation between moderation (r= -0.36,p= 0.017) and total score (r=-0.35,p= 0.021) of HEI and TOC in the total cataract patients. Originality/value To the best of the authors' knowledge, this is the first study on the assessment of the relationship between components of HEI and serum antioxidant indicators in different types of cataract compared to healthy individuals. It could be a start point for more detailed and large-scaled studies, even intervention studies, in this field.