Your gut is your second brain

Author: Dr. Michelle Durkin on 29 November 2016

disease.gutDid you know that you have more receptors for serotonin in your gut than you do in your brain? Also, the bacteria in our gut make more than 90% of important neurotransmitters, serotonin being one of them.

Mental health is interdependent on gut health. It's biochemically that simple.

Serotonin is often known as our happy hormone. No wonder when people slide away from eating lots of real food they feel grumpy, unhappy, and can't deal with stress well. We see this demonstrated most obviously in kids. Who hasn't experienced a two year old on the verge of a temper tantrum after eating sugar all afternoon and it's getting close to bedtime?

Unfortunately conventional medicine has led us to believe that depression is a Prozac or Paxil deficiency. A chemical imbalance in the brain that needs to be fixed by medication. But how did that imbalance occur in the first place and shouldn't we be treated the cause and not the symptom?

Boston-based psychiatrist Dr James Greenblatt says the workings of our gastrointestinal tract—and the bacteria contained within it—affect our mental health.

'The microbiome is the collection of bacteria in the GI tract, and for years we always thought that our thoughts and our feelings affect our GI tract, so we might get stomach aches or we might get diarrhoea when we are nervous. But over the past 20 years or so, we now understand that the gut can affect brain function. What we are finding is that this collection of bacteria, this microbiome if you will, has tremendous neurophysiological effects on mood and behaviour and appetite."

Here are 3 tips on how to keep our gut and therefore our brain healthy:

  1. Eat a low carbohydrate, low sugar, high fibre diet - this means lots of vegetables, some fruit, and adequate protein and fat.
  2. Avoid chronic antibiotic use - if you are chronically on antibiotics for sinus infections, bladder infections, sore throats or acne you are at high risk of damaging your micro biome. Investigate the underlying cause with your Naturopathic Doctor.
  3. Eat fermented foods and take a good quality probiotic daily - consider probiotics like fertilizer for your lawn. We want your gut terrain to be nice and lush with a variety of different bacteria.

Now I would love to hear from you! What did you find surprising about this article? What do you do to keep your gut and consequently your brain healthy? Leave a comment below and I'll be back next week with another edition of Doctor as Teacher Tuesday.

6 Replies to “Your gut is your second brain”

Deanna Dulmage.

I am trying to follow the fodmat diet. It does not included fermented foods. How can I ensure a balanced diet.
Do usse have access to the 23 and me program that I belong to.

Dr Michelle Durkin ND

Hi Deanna,
There are many different opinions on what a “balanced diet” looks like. You may have to abandon your old ideas of what a balanced diet is in order for you to be successful.
If you are following a credible FODMAP food list there are acceptable foods listed in every food group. The category that will be the toughest is nuts & seeds. If you are concerned, consult with a naturopathic doctor. You may also need to supplement your diet for a certain period of time.
Naturopathic doctors in Ontario are not permitted to use 23 and me testing for diagnostic purposes. The best option is for a patient to bring their results to their visit so the information can be taken in context with the rest of the patient’s case.


Great article Dr. D! Speaking of changing diets and supplements, sometimes certain foods and supplements can aggravate gallstone symptoms. I’ve read that taking bile salts can provide fast relief. I see bile salts for sale in stores but the label says they are for baths. Are these safe to ingest or are there specific bile salts for that? And where does one find instructions on proper dosage? thanks!

Dr Michelle Durkin ND

There are a few products that we carry at the office that have bile salts in them. They are Ichol+ by Genestra, Pan Ox 5 by Douglas Labs, and Biogest by Thorne. Each has the bile salts mixed with other digestive aids. I currently do not know of any products that contains bile salts for use in a bath. Maybe you are thinking of Epsom salts?


Thanks for replying Dr. D. Sorry about that, yes I meant to say Epsom salts. What kinds are safe to take orally and how does one estimate a correct amount?

Dr Michelle Durkin ND

I only recommend using Epsom salts in baths. It is safer to take a magnesium supplement to get your magnesium versus drinking Epsom salts. Their use in giving fast relief for gallbladder symptoms is likely because magnesium will help relax the bile duct.

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