It is unknown if fibre intake differs across diabetes status in USA adults and is associated with glycaemic outcomes. This cross-sectional analysis utilised National Health and Nutrition Examination Survey cycles 2013-2018 data to estimate usual total dietary fibre intake in USA adults and across diabetes status (no diabetes, prediabetes and type II diabetes (T2D)). Associations among dietary fibre intake and glycaemic outcomes were also reported across groups. Adults (≥ 19 years) with at least one dietary recall were included. Diabetes status was determined from self-report data and measured HbA1c. Independent samples t tests were used to compare mean (se) intake across sub-populations. 14 640 adults (51·3 % female) with 26·4 % and 17·4 % classified as having prediabetes and T2D, respectively. Adults with T2D reported greater mean (se) dietary fibre intake compared with no T2D for females (9·5 (0·13) v. 8·7 (0·11) g/1000 kcal/d and males (8·5 (0·12) v. 7·7 (0·11) g/1000 kcal/d; P < 0·01)). However, only 4·2 (0·50)% and 8·1 (0·90)% of males and females with T2D, respectively, met the adequate intake for fibre. Fibre intake was associated with lower insulin (β = -0·80, P < 0·01), serum glucose (β = -1·35, P < 0·01) and Homeostatic Model Assessment for Insulin Resistance (β = -0·22, P < 0·01) in adults without diabetes, and no relationships in adults with prediabetes or T2D were found. Although dietary fibre intake was highest among adults with T2D, intake was suboptimal across all groups. In adults without diabetes, dietary fibre intake was associated with improved glycaemic outcomes and insulin resistance; however, these associations were attenuated by anthropometric and lifestyle covariates.
Keywords: Adequate intake; Carbohydrate quality; Glycaemia; Obesity; Prediabetes; Type 2 diabetes.