Wel­come to the sec­ond half of the gut se­ries! To re­cap, last time, we dis­cussed the im­por­tance our gas­troin­testi­nal tract plays in our di­ges­tive sys­tem. It runs from our mouths to our anus and in­cludes or­gans like the oe­soph­a­gus, the small in­tes­tine and the large in­tes­tine.The mi­cro­bio­ta is like a mi­ni uni­verse in the gut with di­verse mi­croor­gan­isms that in­flu­ence our gut health. More and more stud­ies are show­ing the in­flu­en­tial re­la­tion­ship be­tween our guts and our brains and how their sim­i­lar make up con­tin­ues to af­fect the over­all health of our bod­ies.

There are a min­i­mum of 300 species of mi­croor­gan­isms in our di­ges­tive tract and it is per­haps worth point­ing out that our gut is part of this com­plex sys­tem. The Amer­i­can Jour­nal of Nu­tri­tion stat­ed that ‘a healthy mi­cro­bio­me is more re­sis­tant and re­silient to dis­rup­tion... and in­flu­ences the health of its host (our hu­man body) in a 2019 study. A di­et high in processed foods, sodi­um, sug­ar and fat tends to dam­age the good bac­te­ria in the gut where­as, di­ets high in fi­bre for in­stance, do quite the op­po­site. ‘We must re­store our own re­la­tion­ships with gut mi­crobes for gut health’,(TedTalk, 2019) and this can be done, one meal at a time. Per­haps this is what is meant by ‘you are what you eat’.

Re­fer­ring to the sec­ond part of the ax­is, our brains are the most im­por­tant or­gans in our bod­ies; re­spon­si­ble for co­or­di­nat­ing ac­tions and re­ac­tions, mem­o­ries and thoughts. Al­though they will age just like our bod­ies, there is much we can do to en­sure our brain health is top tier. Heav­i­ly in­flu­en­tial is what we eat and drink and if we move our bod­ies or not. We can al­so train our brains in iso­la­tion with ac­tiv­i­ties like med­i­ta­tion. Af­ter all it is al­so a mus­cle so these all im­prove cog­ni­tive func­tion. In ad­di­tion, sub­stances like al­co­hol should be used in mod­er­a­tion and to­bac­co min­i­mal­ly if at all since these have been linked to cog­ni­tive de­cline dis­or­ders like de­men­tia.

Hav­ing a wide va­ri­ety of good gut bac­te­ria has been shown to re­duce symp­toms of anx­i­ety. This shows there is def­i­nite­ly a link be­tween our gut and our brain. Af­ter all, they con­tain many of the same neu­ro­trans­mit­ters. En­ter the gut-brain ax­is which is a link be­tween the cen­tral ner­vous sys­tem and the di­ges­tive sys­tem there­fore pro­vid­ing an in­di­rect path­way be­tween cog­ni­tive and in­testi­nal func­tions. These mi­crobes in our gut in­ter­act with our brain in many ways. A cou­ple in­clude; the gut hor­mone which sig­nals where bac­te­r­i­al prod­ucts pro­duce neu­ropep­tides that en­ter the blood­stream to di­rect­ly in­flu­ence the ner­vous sys­tem. Sec­ond­ly, there is in­testi­nal per­me­abil­i­ty where a syn­drome like leaky gut can be as­so­ci­at­ed with de­pres­sion and this sup­ports the hy­poth­e­sis that gut bac­te­ria can in­flu­ence the pathol­o­gy of cer­tain men­tal dis­or­ders. The gut mi­cro­bio­me is so pow­er­ful that in a fe­cal trans­plant study pub­lished April 2020 in the Amer­i­can As­so­ci­a­tion for the Ad­vance­ment of Sci­ence, in­testi­nal mi­cro­bio­ta was trans­ferred from a pa­tient suf­fer­ing from al­co­holism and on an­tibi­otics to mice which trans­lat­ed in­to anx­i­ety and de­pres­sion in them.

Al­though stud­ies on this par­tic­u­lar re­la­tion­ship are still con­tin­u­ing, a vast amount of re­search has been done to great­ly in­flu­ence our health and well­ness in this re­gard. Di­ets high in fruit, veg­eta­bles, whole grains, un­sat­u­rat­ed fat and pre­bi­otics which stim­u­late the growth of good gut bac­te­ria, prove to have long last­ing health ef­fects on both the gut and the brain. This, cou­pled with ad­e­quate dai­ly ex­er­cise and oth­er habits for stress re­duc­tion are guar­an­teed to have pos­i­tive ef­fects on our gut, our brain, and our en­tire body. Re­strict­ing an­tibi­ot­ic use is al­so ad­vised due to the re­duc­ing ef­fect it has on mi­cro­bio­me di­ver­si­ty.

Next meal­time be sure to think about how your gut- brain ax­is is af­fect­ed!