Does leaky gut actually exist?

Leaky gut is real, although in science it is called 'increased intestinal permeability'. Your gut wall has tiny 'locks' between its cells, called tight junctions, which prevent harmful substances from entering the bloodstream. When those locks become looser, bacterial waste products and pro-inflammatory substances can seep through nonetheless. Several review studies recognise this mechanism as genuine.

Well-known causes include a high-fat diet, excessive alcohol, chronic stress, antibiotics and a disrupted gut microbiome. In people with obesity or type 2 diabetes, researchers observe that beneficial gut bacteria decrease while bacteria that fuel inflammation increase. SARS-CoV-2 can also directly damage gut cells and thereby increase permeability, but that evidence is still more limited.

Leaky gut is associated in research with a wide range of conditions: obesity, type 1 diabetes, fatty liver disease, cardiovascular disease and autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. However, these are almost always observed associations, not proven causes. Whether leaky gut causes the disease or is itself a consequence of it is something nobody yet knows for certain.

What can you do about it yourself? The Mediterranean diet, rich in vegetables, fruit, fish and nuts, is associated with a healthier gut microbiome. Probiotics, prebiotics and omega-3 fatty acids show promising effects on the gut barrier in review studies. Vitamins A, B, C, D and E are also linked positively. However, large clinical trials are still lacking, so the evidence remains preliminary.

A small study with 43 participants, without a control group, tested a herbal formula containing curcumin, aloe vera and glutamine. Permeability normalised in most participants and gut complaints decreased substantially. Because of the small group and the absence of a placebo group, those results are not conclusive. Wait for larger studies before drawing any conclusions from this.