More health and less disease—that’s the goal for all this money and manpower spent on microbiome research.
And yes, scientists have identified clear links between dysbiosis and multiple diseases. But the landscape gets more complicated —though no less promising– when dysbiosis is put under the microscope.
In Meta-analysis of gut microbiome studies identifies disease-specific and shared responses, Claire Duvallet of Massachusetts Institute of Technology and colleagues reported distinct categories of dysbiosis which will potentially make selected treatments better targeted. The study appeared in Nature Communications.
Dysbiosis as a blanket term is not a one-size fits-all kind of label
- It’s known that some diseases are marked by an invasion of pathogens. Colorectal cancer for one is marked by an enrichment of pathogens. In this case, the bad actors could be targeted with narrow-spectrum anti-microbial.
- Others such as inflammatory bowel disease show a depletion of beneficial bacteria. These conditions may be suited for prebiotic or probiotic interventions for enrichment.
- A third dysbiosis is complete breakdown and chaos in community where a complete overhaul such as fecal microbiota transplants would be best.
Thus, diseases may have unique footprints.
Another question: Do diseases share microbiota?
A deep dive into that and other queries was reported on by Claire J. Steves PhD of Kings College in London who spoke recently at the Harvard Probiotics Symposium in Boston which IPA attended. Dr. Steves and her colleagues mined a special collection of data. Gut microbiota profiles are available for over 2700 members of the TwinsUK cohort who have been phenotyped for a range of health factors for over 25 years.
The thought-provoking research appeared in Nature Communications in July, 2018: Gut microbiota associations with common diseases and prescription medications in a population-based cohort
Of the self-reported diseases, 38 were considered as they were noted by more than one percent of the cohort. Gut microbiota profiles from 16S rRNA gene sequencing of stool samples were available for 2737 individuals. Nearly 90% were female and the mean age was 60.
The most common ailments? High cholesterol, allergies, osteoarthritis and high blood pressure—not surprising for this group.
The researchers then used regression models to identify associations between the 68 microbiota markers and the 38 common diseases adjusting for age, BMI, and confounders.
Seventeen diseases had significant associations with at least one microbiota marker. Some were already seen in other studies such as a negative association between Type2 diabetes (T2D) and Clostridia.
But these were new (and quite a mouthful):
Novel associations, both negative and positive:
- Prevotellaceae and food allergy
- Mollicutes and gallstones
- Odoribacteraceae and urinary incontinence
- Deltaproteobacteria and acne
- Lentisphaeria and osteoarthritis
Diversity measures had exclusively negative associations, as did previous reports of reduced gut microbiome diversity in disease.
And the scientists found some prime spots for future exploration: certain conditions even with few cases displayed high associations: IBD, T2D, constipation, recurrent urinary tract infections, food allergies, and celiac disease.
Others were less promising as links were few even when a high number of cases were observed: anxiety, respiratory allergies, and high cholesterol.
The story evolves. The happy ending points to a healthy microbiome for all of us.