(P26-030-25) Assessing the Habitual Intake of Dietary Polyphenols and Their Associations With Hemoglobin A1c by Diabetes Status in the CACTI Cohort

Objectives: Plant-based diets optimize glycemic control in people with type 1 diabetes (T1D), partly due to the diets’ micronutrient and fiber content. Less is known about the habitual intake of polyphenols and its role in hemoglobin A1c (HbA1c) in T1D.

Methods: Data from the Coronary Artery Calcification in Type 1 Diabetes study [n=1416; T1D: n=652; nonDM: n=764], collected at baseline and years 3 and 6, were used to assess polyphenol intake and its association with HbA1c. Participants completed a validated food frequency questionnaire and biochemical analyses at each visit. Polyphenol intake was computed for all plant-based foods and beverages using the Phenol-Explorer database, converting the food to grams and multiplying by the mean polyphenol content. A retention factor was applied to cooked foods. Total polyphenol, flavonoid, and phenolic acid intakes were compared by diabetes status. Longitudinal associations with HbA1c were analyzed using mixed-effect models adjusted for glycemia-related confounders. The exposure and outcome variables were log-transformed for precision.

Results: At baseline, years 3 and 6, the median (IQR) total polyphenol intakes (mg) for those with T1D were 688 (278-1166), 722 (306-1115), and 795 (313-1148), respectively. For those without T1D, the intakes were 724 (281-1150), 788 (299-1091), and 722 (226-1197), respectively. Intakes did not significantly differ by group. In the adjusted mixed-effects model, total polyphenol intake and its subclasses were inversely associated with HbA1c in those with T1D, though not significant. Total polyphenol intake [% change (95% CI)]: -0.27 (-0.56, 0.01) p=0.06, total flavonoid intake: -0.37 (-0.71, 0.06) p=0.09, total phenolic acid intake: -0.21 (-0.45, 0.04) p=0.10. Inconsistent non-significant associations were identified in the nonDM analysis; total polyphenol intake: 0.10 (-0.37, 0.56) p=0.68, total flavonoid intake: -0.18 (-0.92, 0.56) p=0.64, total phenolic acid intake: 0.09 (-0.32, 0.51) p=0.66.

Conclusions: The inverse associations in those with T1D were stronger than the associations in those without T1D, despite not reaching significance. Future research should continue investigating habitual levels of polyphenol consumption in diabetes.

Funding Sources: American Diabetes Association, NHLBI