Effects of a gluten-free diet on gut microbiota and immune function in healthy adult humans.

Gut microbes. 2020;1(3):135-7

Other resources

Plain language summary

The composition of gut bacteria is greatly influenced by diet composition, particularly complex carbohydrates. Currently for patients with coeliac disease, the only therapy is to adhere to a strict gluten-free diet (GFD), which naturally reduces intake of these complex carbohydrates. The aim of this preliminary study was to assess the nutritional quality of the GFD through modifications on the composition and immune properties of the gut microbiota. 10 healthy subjects followed a GFD for one month and faecal microbiota was analysed.  This study showed that inflammatory markers were significantly reduced, however the number of healthy gut bacteria also decreased. Based on these findings, the author concluded that a GFD does not lead to complete normalisation of the gut microbiota, and supports the consideration to promote polysaccharide and probiotic intake in treated coeliac disease patients.


Diet is a major environmental factor influencing gut microbiota diversity and functionality, which might be relevant to subjects following dietary therapies. Celiac disease (CD) is an enteropathy caused by an aberrant immune response to cereal gluten proteins and the only therapy is the adherence to a gluten-free diet (GFD). In this context, a preliminary study was conducted to establish whether the GFD in itself could modify the composition and immune properties of the gut microbiota. The trial included 10 healthy subjects (30.3 years-old), which were submitted to a GFD over one month. Analysis of fecal microbiota and dietary intake indicated that numbers of healthy gut bacteria decreased, while numbers of unhealthy bacteria increased parallel to reductions in the intake of polysaccharides after following the GFD. Fecal samples of subjects under a GFD, which represent an altered microbiota, also exerted lower immune stimulatory effects on peripheral blood mononuclear cells than those of subjects on a regular gluten-containing diet. This addendum presents further discussion on the rationale behind these findings, limitations of the study and possible consequences of dietary counselling in the care process of celiac disease patients.

Lifestyle medicine

Patient Centred Factors : Mediators/Gluten-free diet
Environmental Inputs : Diet ; Nutrients ; Microorganisms
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Stool
Bioactive Substances : Polysaccarides ; Cytokines

Methodological quality

Allocation concealment : Not applicable


Nutrition Evidence keywords : Complexcarbohydrates ; Dietaryfibre ; Shortchainfattyacids ; SCFA