Friends, Lovers, and Microbes

We may share more than good times with our friends and lovers.

“Let us be grateful to people who make us happy, they are the charming gardeners who make our souls blossom.” —Marcel Proust

A lot of our anxieties exist mainly in our own head. We may have a load of troubles, but by dwelling on them, endlessly ruminating on our helplessness, we simply get more anxious.

Give it a break! Talk to someone. Other people are stimulating, keeping your mind engaged — and off your own troubles. Friends don’t just share advice and gossip. Amazingly, they also share microbes. Over time, people tend to spread their microbes around through touch, our shared environment, or just breathing.

Because of the gut-brain axis, that means we may be sharing moods as well. That can be good or bad — but is surely an argument for picking happy roommates.

We do the most sharing with our lovers and spouses, of course. Kissing, hugging, fondling, and sex are terrific ways of sharing microbes. Intimate kissing alone can transfer 8 million bacteria per second between participants. Don’t let that put you off. It’s been happening to you since you were a cute little baby. Somehow, everyone feels entitled to pass on their microbial endowment to a baby’s budding microbiome. In fact, kissing may have evolved specifically for this purpose. Nature is sneaky and none too fastidious.

Sharing is caring

Since microbes can affect our behavior, there is even the suspicion that microbes are nudging us to greater social and sexual activity. From the microbial point of view, humans are enticingly warm ambulatory fermentation vats, perfect for expanding their niche. The bacteria most involved with person-to-person transmission include Bifidobacterium angulatum, Streptococcus thermophilus salivarius, Spirochaetaceae, and Prevotella.

A slight step down in microbe sharing is between casual friends. Even friends of friends transfer some microbes. The more time we spend with someone, the closer the microbial match. Your microbes are shared with your coworkers, people in your clubs, friends at the pub, and schoolmates.

Although this introduces the concept that the blues are contagious, there is a less depressing take-away: when we renovate our own microbiome, we can spread the joy. And, in fact, groups can be a good way to nudge us toward better behavior. Get your friends and lovers to eat more fiber, for instance, and you all may benefit. This is how you turn a vicious cycle virtuous.

There may be some flatulence involved, and if you’re conjuring the Blazing Saddles bean scene, you may not be far off. Expect a little farting in the beginning, but when everyone is tooting, it’s less embarrassing and more orchestral. Fortunately, after a time, it levels off as your microbes become adjusted to the healthier diet.

There are many reasons people get the blues. Poor health, death of a loved one, and financial problems are just a sampling. It’s not all up to microbes! Genes are involved as well. But even here, most of the relevant genes are related to components of the immune system, reinforcing the role of microbes. Your gut may determine how well you can tolerate stress, and a balanced microbiota seems to moderate anxiety.

What to do

If you are a psychiatrist, you can take advantage of this research:

• Ask your patients about gut problems. Depression is strongly comorbid with IBS and IBD.

• You might want to look at blood levels of inflammation.

• Recommend better diets (see below).

• Trial probiotics or prebiotics with patients who are averse or refractory to psychoactive drugs.

Psychobiotics are unlikely to replace antidepressants or anxiolytics, but they can be excellent adjuvant therapies, helping to lower the dosage or the number of drugs used in treatment.

If you are a psychiatric patient, or just suffering the blues, look to your gut:

• Fiber and polyphenols are preferred foods of your beneficial bacteria, so eat foods like artichokes, asparagus, broccoli, leeks, and dark-colored leafy greens.

• Exercise to improve the diversity of your gut microbiota.

• Avoid unnecessary antibiotics. They can be lifesavers, but they are useless against viruses and can damage your gut microbiota.

• Get plenty of sleep and try to synchronize with normal day-night cycles. Your bacteria have circadian cycles too and it helps if you can coordinate with them.

For many mood disorders, microbes may be the main actors. Dealing with them may banish the blues, often without psychoactive drugs and their attendant side effects. What are you waiting for?

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Personal note

Psychobiotics are fascinating and are starting to help millions of people. That’s why I wrote The Psychobiotic Revolution, from National Geographic. But how do you stay on top of it? The science comes in thick and fast, and it takes an insomniac researcher to decode it. I do that so you don’t have to.

In my day job as a scientist, I formulate probiotics and prebiotics. I consult with companies big and small about how they can use biotics to boost performance, mood, and overall health. Recently I formulated a prebiotic/psychobiotic blend for Scanderson Labs. Take a look and tell me what you think!

References

Dinan, Timothy G., Catherine Stanton, and John F. Cryan. “Psychobiotics: A Novel Class of Psychotropic.” Biological Psychiatry 74, no. 10 (November 15, 2013): 720–26.

Anderson, Scott. The Psychobiotic Revolution. National Geographic, 2017.