It's partially because the exact role of intestinal microbiome is still under scrutiny and research. Claims like the one above, while sounding like definitive knowledge, are working theories. No doubt microbiome has an impact on general health, but to what extent is still under some intense debate.
greysneakthief t1_iscw3eh wrote
Reply to comment by SnooDoubts826 in Scientists researching possible candidates for treating Alzheimer's disease found exercise outperformed all tested drugs for the ability to reverse dysregulated gene expression. by shadesofaltruism
It's partially because the exact role of intestinal microbiome is still under scrutiny and research. Claims like the one above, while sounding like definitive knowledge, are working theories. No doubt microbiome has an impact on general health, but to what extent is still under some intense debate.