My focus for the last few years has been on the ME/CFS Microbiome. I decided to test a variety of AI sites for their answering of the question below. Why do I ask this question? Simple, the rate of ME/CFS is very different between men and women, hence the differences of the microbiome may account for this.
What is the difference of reference ranges between 30 year old men and women microbiomes
Women may have more short-chain fatty acid (SCFA) producers (Roseburia, Faecalibacterium), influencing metabolism.
Men may have more bile-tolerant bacteria (Bilophila), linked to high-fat diets.
Perplexity.com
Alpha Diversity
Women generally exhibit higher microbial richness (SV richness) and Shannon diversity indices compared to men in young adulthood,
Taxonomic Composition
Females show higher abundances of Bacteroides, Prevotella, and Faecalibacterium, while males tend to have more Clostridium clusters and Enterobacteriaceae124.
Diversity: Some studies suggest that women in their younger adult years (including around age 30) tend to have a higher alpha diversity (a measure of the variety of species within an individual) in their gut microbiome compared to men of the same age.
Claude 3.7 Sonnet
Key microbiome differences between 30-year-old men and women:
Bacterial diversity: Women often show slightly higher overall microbial diversity
Firmicutes/Bacteroidetes ratio: Men typically have higher levels of Bacteroidetes, while women tend to have higher levels of Firmicutes
Sex-hormone influenced taxa: Women generally have higher abundance of Akkermansia, Bifidobacterium, and certain Lactobacillus species
Bile acid metabolism: Different bile acid profiles between sexes influence microbiome composition
Prevotella vs. Bacteroides: Women often show higher relative abundance of Prevotella compared to men
Grok.com
Women: Higher relative abundance of Firmicutes and Actinobacteria, lower Bacteroidetes. This may contribute to a higher Firmicutes/Bacteroidetes (F/B) ratio, associated with energy extraction from food. Premenopausal women show enriched species like Bifidobacterium, Ruminococcus, and Akkermansia, which are linked to beneficial metabolic effects.Men: Higher Bacteroidetes (e.g., Bacteroides, Prevotella), with men three times more likely to have a stool community type dominated by Prevotella over Bacteroides.
At age 30, women generally show higher gut and oral microbiome diversity, with enriched Firmicutes and Actinobacteria in the gut and Lactobacillus-dominated vaginal microbiomes. Men have higher skin microbiome diversity and gut Bacteroidetes abundance. These differences stem from hormonal and immune interactions, impacting disease susceptibility.
“Understanding these differences is essential, as they can have profound implications for health, particularly in conditions like irritable bowel syndrome (IBS) and metabolic disorders. “
“Research has shown that the microbiome of male mice exhibits higher levels of Firmicutes and lower levels of Bacteroidetes compared to females, contributing to differences in health outcomes and susceptibility to diseases such as CRC”
None of the other bacteria listed below were reference. Lots of discussion on hormones. The response was disappointing.
ChatGPT.com
Similar to DeepSeek above (not a surprise!).
Relative Abundances of Bacterial Genera (typical trends):
Bacterial Genus
More Abundant In
Notes
Bacteroides
Men
Linked with protein and fat-rich diets
Prevotella
Women
Often higher in fiber-rich diets
Akkermansia
Women
Linked to estrogen levels; supports mucosal health
Faecalibacterium
Both
Anti-inflammatory, usually similar in healthy individuals
And this summary
Feature
Men
Women
Microbial diversity
Lower
Higher
Dominant genus
Bacteroides
Prevotella, Lactobacillus
Hormonal effect
Lower
Higher
Butyrate production
Lower
Higher
Bottom Line
Differences were cited for the following bacteria. I suspect everyone has been reported in one or another study. All of the AIs appear to have incomplete answers. Incompleteness is expected, given their methodology of assembling data. The knowledge level is likely typical of most medical professional: reflecting what they have recently read (and not the entire body of available literature)
It was interesting to note that some of the differences were ascribed to male or female eating habits.
My great disappointment is that no microbiome testing company that I am aware of, uses reference ranges that are gender and age based. That makes identifying truly abnormal shifts questionable.
To give a practical example, suppose that you are getting reference range for height instead. You measure people on the street (it happens to be in front of shipyard). We know women tend to be up to 14cm shorter than men, so a bias to males in your sample is ignored. If the shipyard is in India, you get 154 cm. In Holland, 184 cm. So conclusions about a person having “stunted growth” or “excessive growth” based on their height without any reference to appropriate context becomes very suspect. A female that is 140 cm in India could be deemed to have stunted growth — yet is the average height for a woman in India.
CFS Remission 