Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants12

Randomized crossover trial in healthy adult ileostomy participants in London, United Kingdom. Among the active intervention arms, 11 participants were randomized to each porridge condition and 9 were analyzed/completed per arm; participants were aged 20 to 76 years and had undergone proctocolectomy for ulcerative colitis, pure colonic Crohn disease, or lower bowel cancer.

Two oral porridge test meals based on durum wheat endosperm were compared in a randomized crossover design: coarse porridge with intact endosperm particles (about 2 mm) versus smooth porridge with finely milled particles (<0.2 mm). Each meal was consumed within 15 min and provided 55 g starch, 57.8 g available carbohydrate total; the meals were prepared from 77 g durum wheat endosperm cooked in water.

Coarse porridge produced a clearly better postprandial metabolic profile than smooth porridge. Compared with smooth porridge, 120-min incremental AUCs were reduced by 33% for glucose, 43% for insulin, 40% for C-peptide, and 50% for GIP, all with P < 0.01. Peak glucose, insulin, C-peptide, and GIP were also higher after smooth than coarse porridge by 12%, 32%, 37%, and 60%, respectively. GLP-1 and PYY rose after both meals but did not differ significantly, and ileal resistant starch recovery was similar for both meals at about 3 g over 10 h. The authors concluded that preserving wheat endosperm structure slows starch amylolysis and lowers postprandial glycemia and insulinemia.

Very small acute crossover study with only 9 analyzed participants per arm, limiting precision and generalizability. The population consisted of healthy ileostomy participants, so findings may not translate to people without ileostomies or to long-term cardiometabolic outcomes. One participant was excluded for high fasting glucose and one withdrew during the second intervention because of abdominal discomfort.