During this project the investigators will evaluate whether the effects of arabinoxylan oligosaccharides (AXOS) consumption on insulin resistance in participants with metabolic syndrome can be explained by the production of short-chain fatty acids (SCFA). Secondly, the investigators will evaluate whether changes in gut hormone production might explain the effect on insulin resistance.

Inclusion Criteria:

• Age between 18 and 65 years

• Regular diet (3 meals/day on at least 5 days/week)

• Central obese (defined as waist circumference ≥ 94cm for Europid men and ≥ 80cm for Europid women, with ethnicity specific values for other groups)

• Insulin resistant: HOMA-IR > 1.7 or fasting glucose > 100mg/dL

• And one of the following three factors:

  • Elevated TG level: ≥ 150 mg/dL (1.7 mmol/L)
  • Decreased HDL cholesterol level: < 40 mg/dL (1.03 mmol/L*) in males and < 50 mg/dL (1.29 mmol/L*) in females
  • Elevated blood pressure (BP): systolic BP ≥ 130 or diastolic BP ≥ 85 mm Hg

Exclusion Criteria:

• Low calorie diet or other special diet during the study or during the last month prior to the study
• Serious chronic disease of the gastrointestinal tract, such as inflammatory bowel disease (Crohn's disease or ulcerative colitis), irritable bowel syndrome, chronic constipation (less than 3 bowel movements a week), chronic frequent diarrhoea (more than 3 stools a day), clinically relevant lactose intolerance, …
• Use of antibiotics during the last month before starting the study
• Abdominal surgery in the past (except from appendectomy)
• Use of medication that affects the gastro-intestinal tract during the last 2 weeks prior to the study including spasmolytics, anti-diarrhoea medication, anti-constipation medication, and/or pre- or probiotic supplements (e.g. lacteol, Enterol)
• Pregnancy, pregnancy desire or lactation
• Diabetes (type 1 or 2), i.e. HbA1c > 6.5 %
• Abnormal haemoglobin (Hb) levels in blood, men must have an Hb level between 14.0 and 18.0 g / dL and women between 12.0 and 16.0 g / dL.