The acute effects of variations in the flour composition of crackers on the glycemic index and glycemic responses in healthy adults

This study assessed the glycemic index (GI) and glycemic load (GL) of three crackers formulated with different flours: a control cracker (CC) made with conventional flour, one with 30% whole wheat flour substitution (WWC), and another with 30% sunflower seed flour substitution (SFC). This study aimed to explore the impact of these substitutions, which vary in protein and fiber content, on the glycemic responses compared to a reference glucose drink. In a randomized controlled, crossover design, 11 healthy participants (mean age 23.5 ± 1 years; 7 women; BMI 23 ± 1 kg/m2), consumed cracker meals (CC, WWC, and SFC) each providing 50 g of available carbohydrates, and a 50 g glucose reference in separate sessions. The SFC crackers provided low GI and GL values (GI: 53 on the glucose scale, GL: 6 per serving), whereas the WWC and CC crackers provided high GI (GI: 77 and 90 on the glucose scale, respectively) and medium GL values (11 and 12 per serving, respectively). Compared with the glucose reference and CC crackers, only SFC induced lower postprandial glucose concentrations, lower glucose excursions, and lower peak glucose values. All crackers were rated as enjoyable and associated with increased satiety. SFC moderated postprandial glycemic responses compared to CC and the reference (D-glucose), but not WWC. These effects may be attributed to the soluble fibers and protein content of the SFC. These findings suggest potential benefits for body weight management and glycemic control, warranting further investigation of the role of flour substitutions in healthy snack options. This trial has been registered at Clinicaltrials.gov (NCT05702372).