A while ago, I came across this interesting and very important review in Cell (a very reputable journal), on how gut microbes (part of your microbiome) can affect the aging process. Ten years ago people would have thought this was impossible!
The review, published in January 2014, is by Caroline Heintz and William Mair, both from Harvard. The article can be found here: “You are what you host: microbiome modulation of the aging process.“. To summarize, the microbes living in symbiosis with invertebrates, and possibly other animals (mostly in the gut, but also in other places, like the mouth or on the skin), can affect the rate at which aging occurs. This could occur by the microbial production of compounds that affect the expression of genes, or possibly by the microbes metabolizing compounds into products that have direct effects on host physiology. There is also evidence to suggest that different microbial species may have different effects. It makes sense if you think of how long digestive systems have existed in symbiosis with microbes- maybe we and they have co-evolved.
Most of the work cited in this review has been done with invertebrates, particularly nematodes, which have been intensively studied for many years as model organisms. How exciting if the results from these studies are supported by work done with mammals! Until we know more about how microbes interact with mammals, the best thing you can do is try to make sure you eat a healthy, balanced diet with lots of fruits and vegetables, get regular sleep (disrupting circadian rhythms can lead to changes in your gut microfloral composition and changes in your body, like a tendency to gain weight), and get regular exercise (in addition to health benefits, most cardio exercise helps your gut move food along by peristalsis- there’s a reason why for many years people would take walks after meals to help with digestion!). If you want to take a probiotic, I can’t recommend a specific product, but you may be able to find more information at sites like probiotics.org.
Have a great day!