A persons microbiome is largely decided shortly after birth, one of the reasons breastfeeding is encouraged if only briefly. After this period of "accepting" the immune system locks down and tends to destroy the newcomers. That said the manipulation of microbiomes has great potential to aid in everything from weight loss to disease.

Like most things with science, things that are "groundbreaking" and what you want to hear anyway tend to make the news and Dr Oz, while good science is slow, methodical and tedious. If you aren't getting your science news from accredited peer reviewed publications then you can safely ignore it.

That said, this is a good resource to check your data, there are others out there too. Searches only peer reviewed publications but is much harder to read if you don't have the background.

[doaj.org]