The association between dietary glycemic index, glycemic load and diet quality indices in Iranian adults: results from Isfahan Healthy Heart Program.

To assess the association between dietary glycemic index (GI), glycemic load (GL) and dietary quality indices in Iranian adults. This cross section was conducted among 1571 Iranian adults aged  ≥19 years. GI, GL and diet quality indices were estimated by 24-h recall and DDS was calculated using a validated 48-item food frequency questionnaire. Participants who were in the top tertile of GI had lower healthy eating index (HEI) (57.2 ± 7.8 versus 55.6 ± 8.7; p < 0.001), dietary diversity score (DDS) (3.6 ± 0.9 versus 3.3 ± 1.1; p < 0.001) and nutrient adequacy ratios (NARs) for Zn, Ca, vitamin C and B2. Individuals in the lowest tertile of GL had lower HEI, MAR and NARs for Zn, vitamin B2, B3, B6, B12, vitamin D. Both GI and GL were positively related to dietary diversity score (DED) (p < 0.001). The inverse associations for GI and GL with diet quality indices may suggest the relevance of carbohydrate source in determining the diet quality indices.