Sharing a Microbiome

There’s a lot of talk about microbiome in the news these days. Fecal transplant, anyone? But it seems that one doesn’t have to go to that extreme to share one’s microbiome with another. Apparently one shares all sorts of little critters living in and on one’s body merely by living with another person.

As with many things in life, it starts with the mother. “During an infant’s first year of life, half of the microbial strains in their guts were shared with their mothers. The extent of overlap decreased as children aged — but did not vanish. Older people, aged 50–85, still had gut microbe strains in common with their mothers.”

As I read this I thought of other research suggesting a connection between the gut biomeme and diseases like cancer and diabetes. I’m definitely not a medical scientist, but I wonder if we may learn someday that close contact between people could in fact contribute to one person’s “catching” diabetes from another. I suppose the contagion would be indirect rather than direct, but still.

Clearly there are all sorts of questions here. Perhaps the biggest one is why doctors haven’t noticed a pattern of shared diseases. But there are others. Is there a causal relationship between particular elements in microbiome and particular diseases? If so, in which direction does the cause work: is the microbiome the cause or the effect of the disease? Are the elements of the microbiome that are associated with disease among those that are shared by people in close proximity with each other?

As I said, I’m not a scientist. Put this in the category of wild speculation.