This study will explore how a natural food ingredient called oligofructose affects blood glucose levels, lipid profiles, inflammation biomarkers, and gut bacteria in Saudi adults with type 2 diabetes. Oligofructose is a type of dietary fiber found in foods such as onions, garlic, and bananas. It is known to help the growth of "good" bacteria in the intestine, which may improve digestion and metabolism.

A total of 100 adults (50 with type 2 diabetes and 50 without diabetes) will take part in this research. Participants will be randomly assigned to receive either oligofructose or a placebo twice daily for 12 weeks. Blood tests will be done at the beginning and at weeks 4, 8, and 12 to check changes in blood glucose, lipid profiles, and inflammation.

The goal of this study is to find out whether adding oligofructose to the diet can help people with diabetes improve their blood glucose control, reduce inflammation, and support a healthier balance of gut bacteria.

Type 2 diabetes mellitus (T2DM) represents a major public health challenge and is frequently associated with metabolic abnormalities, including dyslipidemia, obesity, and cardiovascular disease. Emerging evidence indicates that the gut microbiota plays a critical role in regulating host metabolism, inflammation, and glucose homeostasis. Alterations in gut microbial composition have been consistently observed in individuals with T2DM and obesity, suggesting that modulation of gut microbiota may represent a therapeutic target for metabolic disease management.

Prebiotics are non-digestible, fermentable dietary components that selectively stimulate the growth and activity of beneficial gut bacteria. Oligofructose, a well-studied prebiotic carbohydrate, resists digestion in the upper gastrointestinal tract and undergoes fermentation in the colon, leading to the production of short-chain fatty acids that influence glucose metabolism, lipid metabolism, appetite regulation, and inflammatory pathways.

Previous human and animal studies have reported mixed but promising results regarding the effects of oligofructose on glycemic control, lipid profiles, body weight, and inflammatory markers. Some studies demonstrated improvements in fasting blood glucose, lipid parameters, insulin sensitivity, and body weight, while others reported limited metabolic effects despite favorable changes in gut microbiota composition. Differences in study populations, dosages, duration, and baseline metabolic status may account for these inconsistencies.

Individuals with T2DM exhibit distinct gut microbiota profiles compared to non-diabetic individuals, including increased abundance of gram-negative bacteria and elevated circulating lipopolysaccharides, which may contribute to metabolic endotoxemia and insulin resistance. However, data regarding the impact of prebiotic supplementation on gut microbiota and metabolic outcomes in the Saudi population are limited.

This study aims to evaluate the effects of oligofructose supplementation on body weight, glycemic control, lipid profile, inflammatory markers, and gut microbiota composition in individuals with type 2 diabetes. Unlike studies using probiotics, this intervention focuses on modulating endogenous gut microbiota through prebiotic supplementation without introducing live microorganisms.

Hypothesis:

Prebiotic oligofructose supplementation will lead to improvements in body weight, glycemic control, lipid profile, and inflammatory status, mediated in part through favorable modulation of gut microbiota composition.

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.

Individual participant data (IPD) from this study will not be shared outside the research team. All data will remain confidential and will be used solely for this study in accordance with institutional ethical guidelines and participants' informed consent.

This is a double-blind study. Participants, care providers, and outcome assessors are unaware of whether participants receive oligofructose or placebo. Only the investigator responsible for randomization knows the group assignments to allocate participants correctly.