Could a fiber from onions and bananas help tame diabetes?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Saudi, both males and females. * Aged between 45-60 years old * BMI between 25 - 30 kg/m2 * No antibiotic use for the last six months Cases: * Type 2 diabetes. * Duration of diabetes ≥ 5 years * HbA1c ≥ 6.5-8.0 Controls: (subjects with normal OGTT results) * Fasting plasma glucose (FPG) \< 100 mg/dl (5.6mmol/l) * A1C less than 5.7% * 2-hour post-load glucose \< 140 mg/dl (7.8 mmol/l) Exclusion Criteria: 1. Patients with Type 1 diabetes. 2. Pregnant \& breastfeeding females. 3. Any serious disease such as renal or hepatic disease, thyroid functions, coeliac disease, or the presence of gastroparesis. 4. Use of weight-loss treatments within 3 months before inclusion 5. Diabetic patients on acarbose, metformin (\> 1 g/day), and GLP-1 medications. 6. Use of antibiotic drugs for the last 3 months of treatments that influence gut microbiota composition. 7. Bypass surgery, Laparoscopic Sleeve Gastrectomy (LSG), or colon restriction. 8. Chronic gastrointestinal disorder (except irritable bowel syndrome). 9. Patients with a history or symptoms of obstruction or Inflammatory bowel disease 10. Atypical diets (such as vegetarians, vegans, and heavy consumption of dietary supplements). 11. Use of pre/probiotics or fiber supplements within 3 months before inclusion. 12. Any drug that can interfere with food absorption or gut flora, such as chronic consumption of loperamide, cholestyramine, antacids, H2-receptor blockers, proton pump inhibitors, fibrates, corticosteroids, or sex steroids, omega-3 unsaturated fatty acids acid, or anti-inflammatory drugs. 13. Autonomic neuropathy 14. Any immune-compromised disease. 15. Daily alcohol consumption \> 30 g. 16. Involvement in another clinical trial in the past 6 months. 17. Any legal incompetence or mental inability to provide consent.