Leaky gut is a term used to describe increased intestinal permeability. In simple terms, the gut lining becomes less selective, allowing substances that should stay inside the gut to pass into the bloodstream. This can drive inflammation, immune activation and metabolic dysfunction over time.

One of the most important protective factors for the gut lining are short chain fatty acids (SCFAs).

What are SCFAs

SCFAs are fatty acids produced when beneficial gut bacteria ferment dietary fibre. The main SCFAs are acetate, propionate and butyrate. Of these, butyrate plays the most critical role in gut health.

Butyrate is the primary fuel source for the cells lining the colon. It helps maintain tight junctions between cells, supports immune balance and reduces inflammation. When SCFA production is low, the gut lining becomes more vulnerable to damage.

Causes of leaky gut

Leaky gut rarely has a single cause. It usually develops when several stressors stack up over time, including:

• Low fibre intake and poor microbial diversity
• Ultra processed foods and food additives
• Chronic high blood sugar and elevated insulin
• Excess omega 6 intake and a poor omega 3 to 6 ratio
• Alcohol overuse
• Chronic stress and poor sleep
• Repeated antibiotic use
• NSAIDs and certain medications
• Gut infections or unresolved digestive issues

Common symptoms

Symptoms vary between individuals and can include:

• Bloating, gas and abdominal discomfort
• Diarrhoea or constipation
• Food sensitivities or intolerances
• Fatigue and brain fog
• Joint or muscle pain
• Skin issues such as acne or eczema
• Autoimmune flares
• Sugar cravings and appetite dysregulation

Practical solutions to support gut integrity

Supporting SCFA production is a key strategy for improving gut health.

• Increase intake of fermentable fibres such as vegetables, resistant starch and whole plant foods
• Focus on plant diversity rather than single fibre sources
• Support digestion with strategies such as apple cider vinegar
• Consider spore forming probiotics which are more resilient and may support gut balance
• Improve omega 3 intake and reduce excess omega 6 rich processed foods
• Address blood sugar control, stress and sleep alongside nutrition

The bottom line

SCFAs, particularly butyrate, act as a critical link between diet, the gut microbiome and metabolic health. By feeding beneficial bacteria and reducing inflammatory drivers, you support gut barrier integrity and create a foundation for better energy, immune balance and long-term metabolic health.