What dietary modifications should I advise for patients with SIBO to help alleviate their symptoms?

For patients with small intestinal bacterial overgrowth (SIBO), the provided UK guidelines primarily focus on dietary management for Irritable Bowel Syndrome (IBS), which can present with similar symptoms, rather than specific SIBO dietary modifications ¹,². While a recent publication addresses the diagnosis and treatment of SIBO (Silva et al., 2025), the specific dietary recommendations from this source are not detailed in the provided context.

Based on the general dietary advice for IBS, which may help alleviate overlapping symptoms, you can advise patients on the following:

• Regular Meals and Healthy Eating: Encourage patients to eat regular, balanced meals and avoid missing meals or leaving long gaps between eating ¹,².
• Fluid Intake: Advise drinking at least 8 cups of fluid per day, primarily water or other non-caffeinated drinks like herbal teas ¹,². Restrict tea and coffee to 3 cups per day ².
• Fibre Adjustment: Review and adjust fibre intake according to symptoms ¹,². Patients should be discouraged from eating insoluble fibre, such as bran, wholemeal or high-fibre flour and breads, and whole grains like brown rice, as this may worsen symptoms ¹,². If an increase in dietary fibre is advised, it should be soluble fibre, such as ispaghula powder or foods high in soluble fibre like oats and linseeds ¹,². Gradually increase soluble fibre intake to minimise flatulence and bloating ¹.
• Limiting Certain Foods: Patients should reduce their intake of alcohol and fizzy drinks ². It may also be helpful to limit high-fibre foods and reduce intake of 'resistant starch', often found in processed or re-cooked foods ². Limit fresh fruit to 3 portions per day (approximately 80g per portion) ². For those with diarrhoea, advise avoiding sorbitol, an artificial sweetener found in sugar-free sweets (including chewing gum), drinks, and some diabetic/slimming products ². Patients experiencing wind and bloating may find it helpful to eat oats (e.g., oat-based breakfast cereal or porridge) and linseeds (up to 1 tablespoon per day) ².
• Probiotics: If a patient chooses to try a probiotic supplement, advise them to take the product for at least 4 to 12 weeks while monitoring the effect, and to discontinue if there is no improvement in symptoms ¹,².
• Specialist Dietary Management: If symptoms persist despite general lifestyle and dietary advice, further dietary management, including single food avoidance and exclusion diets (such as a low-FODMAP diet), should only be given by a healthcare professional with expertise in dietary management, such as a dietitian ¹,². This is crucial to ensure the patient's diet remains balanced and nutritious, preventing inadequate nutrient intake and potential malnutrition ¹.