Gut Microbiome Tests: Are They Worth It? A Dietitian Reviews the Evidence (2026)
Article content originally from Rachel Eagleton, a Registered Nutritionist. Recently reviewed and
updated by Hannah Pritchard, a Registered Dietitian (UK) and Researcher.
Gut microbiome tests are becoming increasingly popular, with companies promising
personalised nutrition advice based on a simple stool sample. The idea may certainly be
appealing, but can a gut microbiome test really tell you what to eat?
The short answer is not yet.
Microbiome research is one of the fastest-growing areas of nutrition science, but commercial
gut microbiome testing has outpaced the evidence. As Registered Dietitians, we’re excited
about where the research is heading while remaining committed to evidence-based practice.
Read on to discover what a gut microbiome test is, the real evidence behind it, and what
happened when nutritionist Rachel Eagleton trialed a commercial microbiome stool test.
Although commercial testing has limitations, there are several evidence-based ways to support
a healthy gut microbiome, outlined on this page.
Quick click contents:
What is a Gut Microbiome test?
What happened when a Nutritionist tried a Gut Microbiome test?
Can a Gut Microbiome test tell you what your gut needs?
Does the science behind Gut Microbiome testing support personalised nutrition?
How to improve your gut health without a Gut Microbiome test
What is a Gut Microbiome Test?
A gut microbiome test, sometimes called a stool microbiome test or gut bacteria test, analyses genetic material from a stool/poo sample to estimate which microorganisms are present in your gut. Most commercial tests use DNA sequencing to generate reports alongside personalised dietary or supplement recommendations (1).
The challenge isn’t detecting microbial DNA; it’s knowing what those findings actually mean.
Your gut microbiome changes naturally over time and is influenced by diet, medications, exercise, sleep, stress and many other factors (1). We also don’t yet have an agreed definition of a single “healthy” gut microbiome or clinically validated reference ranges that may allow commercial gut health tests to diagnose disease or prescribe a personalised diet yet (1,2).
In 2025, an international panel of experts concluded that there is currently insufficient evidence to support routine clinical microbiome testing and that consumer tests should not replace a clinical assessment (2).
A 2026 study also found considerable variation in results between commercial testing providers, highlighting ongoing challenges with standardisation and interpretation (3).
A gut microbiome test differs from an allergy or intolerance test, and we've written a separate blog on food intolerance testing too.
What happened when a Nutritionist tried a Gut Microbiome test?
Nutritionist Rachel Eagleton decided to trial the Microba Insight microbiome test herself. She wanted to understand whether the personalised report was translated into practical nutrition advice.
Her report suggested increasing wholegrains, while her husband’s report recommended eating more vegetables and diversifying grain choices by including foods such as quinoa and rice.
Interestingly, these recommendations closely mirror the advice Registered Dietitians already give. Current evidence consistently supports eating a diverse range of plant foods, wholegrains, and dietary fibre to promote gut health (1,4). This can make microbiome reports feel highly personalised. Still, many of the dietary recommendations they generate are already consistent with established healthy-eating guidelines rather than being unique to an individual’s microbiome (1,4).
Can a Gut Microbiome test tell you what your gut needs?
Only in part.
Most commercial gut microbiome tests tell you which microorganisms are living in your gut, but they can't yet tell the whole story.
Researchers are now becoming more interested in what these microorganisms are actually doing. A DNA-based microbiome analysis provides useful information about which microbes are present. Still, it doesn't directly measure how active they are or all the beneficial compounds they're producing (5).
Researchers believe understanding the function of the gut microbiome, not just which bacteria are present, will be an important step towards truly personalised nutrition. However, that science is still evolving, and we're not there yet (4,5).
Does the science behind Gut Microbiome testing support personalised nutrition?
The short answer - not yet.
Large studies show that diet, genetics, lifestyle and the gut microbiome all influence how individuals respond to food (4).
Researchers are actively exploring microbiome-informed personalised nutrition, but a single commercial gut microbiome test cannot yet reliably determine the best diet for an individual (2,4,5).
Although the future is promising, today’s strongest evidence still supports healthy dietary patterns that benefit almost everyone.
How to improve your gut health without a Gut Microbiome test
Instead of relying on an expensive gut microbiome test, you may want to focus on habits consistently supported by current research:
· Eat a wide variety of plant foods (6,7).
· Include fibre-rich foods such as vegetables, fruit, legumes, beans, pulses and wholegrains (6,7).
· Choose predominantly minimally processed foods where you can (8).
· Try different gut-friendly yogurts and explore the best yoghurt for gut health.
· Consider asking a Registered Dietitian about trying suitable probiotics, specific to your needs (9).
· Stay physically active, prioritise sleep and manage stress (10,11).
· You can also get advice from a Registered Dietitian if you have ongoing digestive symptoms. If you need more support, you can contact our team for further information.
Our guide on 'why does gut health matter' provides you with even more suggestions to support your gut health with 10 practical tips included.
Choosing gut-friendly recipes may also help. For example, try our fibre-rich recipes including high fibre blackberry porridge, pickled red onions or a simple homemade hummus recipe.
Gut Microbiome Test FAQs
Are gut microbiome tests worth it?
Commercial gut microbiome tests can provide interesting information about your gut bacteria, but current evidence does not support using them to diagnose disease or prescribe personalised diets (1,2.3).
Can a gut microbiome test tell me what foods I should eat?
No. Personalised nutrition research is progressing rapidly, but scientists cannot yet accurately determine a person’s optimal diet (2,4,5) from a single stool sample.
What’s the best way to improve your gut microbiome?
The strongest evidence supports eating a varied, fibre-rich diet containing vegetables, fruit, legumes, wholegrains, nuts and seeds alongside regular physical activity and other healthy lifestyle habits (1,4,6,7,8).
Summary - Gut Microbiome Tests: Are they worth it?
Research into the gut microbiome and personalised nutrition is advancing rapidly, but the evidence isn't yet strong enough for commercial gut microbiome tests to provide reliable personalised dietary advice (1).
For now, the best way to support your gut health is through a varied, fibre-rich diet and other healthy lifestyle habits that are consistently backed by evidence.
If you’re experiencing digestive symptoms or want practical advice on improving your gut health, our Registered Dietitians can help you focus on what the evidence actually supports, not the marketing.
Whether you’re managing IBS, increasing your fibre intake or simply looking to optimise your nutrition, we’re here to help. You can book a consultation to get started.
Key Takeaways
· Gut microbiome testing is an exciting area of research, but there isn’t enough evidence to support it currently.
· Current commercial tests cannot reliably prescribe personalised diets.
· The strongest evidence still supports eating a varied, fibre-rich diet and maintaining healthy lifestyle habits.
· If you have ongoing digestive symptoms, seek advice from a Registered Dietitian.
References
1. Guts UK Charity. Gut microbiome (poo) testing. Guts UK Charity; 2026 May. Available from: https://gutscharity.org.uk/advice-and-information/testing-and-monitoring/gut-microbiome-poo-testing/
2. Porcari S, Mullish BH, Asnicar F, Ng SC, Zhao L, Hansen R, et al. International consensus statement on microbiome testing in clinical practice. Lancet Gastroenterol Hepatol. 2025;10(2):154-167. doi:10.1016/S2468-1253(24)00311-X.
3. Servetas SL, Gierz KS, Hoffmann D, Ravel J, Jackson SA. Evaluating the analytical performance of direct-to-consumer gut microbiome testing services. Commun Biol. 2026;9:269. doi:10.1038/s42003-025-09301-3.
4. Segev T, Barak D, Zahavi L, Godneva A, Rein M, Krongauz D, et al. Diet–microbiome associations in 10,068 individuals from the Human Phenotype Project to guide personalized nutrition. Nat Med. 2026;32:1884-1894. doi:10.1038/s41591-026-04312-x.
5. Arif L, Abbasi MM, Raza AA, Samadi A. From microbiome profiling to precision medicine: diagnostic and therapeutic potential in gastrointestinal disorders: current evidence, challenges, and future directions. Ann Med Surg (Lond). 2026;88(6):3348-3359. doi:10.1097/MS9.0000000000005027.
6. British Dietetic Association. Fibre. Birmingham: British Dietetic Association; 2021. Available from: https://www.bda.uk.com/resource/fibre.html
7. Koh A, De Vadder F, Kovatcheva-Datchary P, Bäckhed F. From dietary fiber to host physiology: short-chain fatty acids as key bacterial metabolites. Cell. 2016;165(6):1332-1345. doi:10.1016/j.cell.2016.05.041.
8. Ianiro G, Calabrese C, Lopetuso LR, Cammarota G, Scaldaferri F, Gasbarrini A, et al. The detrimental impact of ultra-processed foods on the human gut microbiome and gut barrier. Nutrients. 2025;17(5):859. doi:10.3390/nu17050859.
9. Dimidi E, Christodoulides S, Fragkos KC, Scott SM, Whelan K. The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014;100(4):1075-1084. doi:10.3945/ajcn.114.089151.
10. Bressa C, Bailén-Andrino M, Pérez-Santiago J, González-Soltero R, Pérez M, Montalvo-Lominchar MG, et al. Differences in gut microbiota profile between women with active lifestyle and sedentary women. PLoS One. 2017;12(2):e0171352. doi:10.1371/journal.pone.0171352.
11. Wang Z, Chen WH, Li SX, He ZM, Zhu WL, Ji YB, et al. Gut microbiota modulates the inflammatory response and cognitive impairment induced by sleep deprivation. Mol Psychiatry. 2021;26(11):6277-6292. doi:10.1038/s41380-021-01113-1.
