Gut and Psychology Syndrome



We are experiencing an epidemic of brain related disorders in our modern western world.

14% of Australian children between the ages of 4 to 17 have mental health problems and currently 1 in 5 Australians will experience a mental illness during their lifetime. Post Natal Depression affects 10 to 20% of new mothers. At least 1 in 150 children are diagnosed with Autistic spectrum disorders, whereas 20 years ago there were 1 in 10,000 children diagnosed on the spectrum. Although better diagnosis can explain some of the dramatic rise in these and other brain disorders it does not account for the dramatic increase we are currently experiencing. Genetics is often used as a cause of mental illness however genetic changes take time and do not change as quickly as statistics are showing and modern science now clearly states that it is our environmental influences that turn gens on and off and we are not at the mercy of our 'genes'.

Dr Natasha Campbell-McBride and Bronwyn Sach at Sydney GAPS Practitioner Training

Dr Natasha Campbell-McBride and Bronwyn Sach at Sydney GAPS Practitioner Training

There are many researchers and health practitioners really questioning and investigating what is going on to bring about so much mental illness, even in our young children. Dr Natasha Campbell-McBride has investigated deeply into the causes of mental illness and, drawing from a wide research base and from her own personal and clinical experience, has expanded what is known as the gut-brain connection. She has found that what is happening in the gut, or the digestive system, is directly affecting the brain. The state of the persons gut affects the way the brain grows, develops, and how it functions, affecting how we feel, process information, communicate and even think.

The gut brain connection

It can seem like quite a leap to think about the digestive system/gut when looking at treating brain disorders such as autism, anxiety and depression. Simply put, the digestive system feeds directly into the bloodstream and the blood travels throughout the body including the brain. Whatever is happening in the digestive system will have an effect on the rest of the body including the brain. The digestive system digests the food that we eat, but there is also an extensive ecosystem of bacteria, viruses, yeasts and many other microscopic organisms that is unique to every individual - our gut flora. These micro-organisms also digest the foods we eat and produce many other substances apart from the nutrients from food, some beneficial and some toxic. This is also fed into the blood stream and influences the rest of t he body including the brain.

The gut has also been referred to as our second brain. Both your brain and your gut are created from the same tissue during foetal development and they are connected via the blood stream and also via a major nerve, the vagus nerve. It has been established in recent times that the vagus nerve, which runs from the brain stem down to the abdomen, is the primary route gut flora use to transmit information to the brain.

Examples that illustrate how the gut affects the brain include:

  • Alcohol: is ingested and enters the gut where it is absorbed into the blood stream, rapidly affecting the brain. Alcohol and its by-products are also produced in the gut of those with Candida spp overgrowth and this will also enter the blood stream and effect the brain

  • Pharmaceutical drugs: taken orally will be absorbed into the blood stream via the gut and reach many areas throughout the body including the brain

  • Neurotransmitters: a large percentage of our 'brain chemicals' are produced in the gut including serotonin, noradrenalin, enkephalins and benzodiazepine

  • Detoxification: relies on good liver and gut function. When neurotransmitters have performed their function and are spent it is important that they be deactivated and excreted (detoxified) to avoid disrupting the delicate chemical balance within the brain and body. Also, there are many environmental toxins that are known to disrupt brain function and these need to be detoxified via the liver and gut

There is a delicate balance of brain chemicals (hormones and neurotransmitters) influencing how the brain develops, how we feel and think and our very personality. When this system is interfered with by toxins and nutritional deficiencies, the balance is upset

What is normal digestion?

Digestion is a highly complex process. In order to get an idea what is happening in the digestive system to bring about brain disorders, including depression or autism, it is useful to look at the process of normal digestion.

Digestion is a process of turning large molecules of food into smaller and smaller molecules, down to the simplest raw materials that the body can then use for all its many processes. This involves many steps including one of the main enzymes, stomach acid or HCL.

The basic steps of digestion:

  1. Hunger: anticipation of food, the thoughts, smells and the sight of food begins to prime the digestive system for food by stimulating the appropriate digestive juices

  2. Mouth: chewing mechanically breaks down the food into a semi-liquid mass with the help of saliva so that the enzymes can easily mix in with and access food. Chewing helps liberate nutrients and salivation and the microbes in the mouth start to chemically break down starches and signals the stomach and small intestine that food is on its way

  3. Stomach: mechanical and chemical breakdown of food continues in the stomach. HCL (stomach acid) and pepsin released into the stomach start to chemically break down proteins and fats and the strong stomach muscles churn and knead the food. Intrinsic factor is also secreted into the stomach which is necessary for the assimilation of vitamin B12

  4. Small Intestine: once the acidic contents from the stomach enter the small intestine the pancreas secretes enzymes which break down proteins, carbohydrates and fats and the liver and gall bladder secrete bile which digests fats. The 6-7meters of small intestine is where most of the chemical digestion and absorption takes place. The pancreatic enzymes, bile, gut flora and various brush border enzymes of the small intestine continue the digestion of proteins, fats and carbohydrates. Absorption takes place via small projections all over the wall of the small intestine called villi

  5. Colon: within the colon, beneficial flora reside on the gut wall and produce various digestive enzymes which contribute to some of the final steps in digestion and produce a many beneficial substances for us including Butyric acid. Absorption of water and electrolytes occurs in the colon and the now solid mass (mostly made up of bacteria) is moved along via strong muscular contractions to the end of the digestive system, the rectum, where the desire to evacuate is felt

When healthy, our gut wall is a semi-permeable barrier and active transport system to help maintain control over what enters the blood stream and what does not.

What about gut flora?


"It seems that in our modern world each generation is developing more pathogenic flora"

Our 1-2 kg worth of gut flora is an internal ecosystem of trillions of micro-organisms lining the digestive system in a thick band. There are beneficial (health promoting) and pathogenic (disease promoting) organisms. Our beneficial flora consists of different types of bacteria, viruses, fungi and parasites which protect us against pathogenic microbes, or germs. When the organisms are predominantly beneficial then health follows, when they are predominantly pathogenic then disease follows. Most of the species on the gut wall have not been studied as they cannot yet be cultured, however technology is now being refined that can allow for DNA recognition of our microbes. There is a large amount of research going on throughout the world to learn more about our bodies flora and how it differs in every individual.  One such project is studying the health consequences of different flora, Human Microbiome Project.

The absorptive surface of the small intestine is lined with miniscule finger-like projections called villi and microvilli. The cells lining the villi and microvilli are called enterocytes. This surface layer of enterocytes has a very high cell turnover and demands a high nutrient intake to maintain this constant renewal process. The constant renewal is ruled by the resident gut flora. Without beneficial flora these cells (enterocytes) are less able to perform their function of digestion and absorption.

Our beneficial gut flora are essential to maintain health. Roles of beneficial flora are numerous and include:

  • Digestion: as mentioned above, the beneficial flora have an important role to play in the final steps of digestion including the digestion of lactose and casein from dairy and gluten from grains

  • Protection: by inhabiting the gut wall and protecting their own environment they protect us also against invading pathogens. Beneficial flora produce most anti-biotic anti-viral and anti-fungal substances known plus substances which activate our immune system

  • Maintain/nourish the gut lining: beneficial flora supplies many essential nutrients which feed the gut lining regulating and supporting the high turnover of cells

  • Vitamins and minerals: many vitamins are produced in the gut by beneficial flora including vitamin K2, folic acid and most B vitamins. Beneficial flora produce substances which assist us to absorb minerals from out diet. Beneficial flora also protect our internal environment from pathogenic organisms such as Actinomyces spp and Mycobacterium spp which consume iron as food and will leave the host anaemic regardless of how much iron is being consumed

  • Immune modulation: the gut flora is in direct contact with our immune system and has a powerful influence over how the immune system develops and functions. One role of the immune system is regulation of inflammation. Inflammation contributes greatly to brain diseases including depression and autism. Regulating the immune system helps to reduce inflammation. Good gut flora ensures the production of different immune cells (immunoglobulins) and balances the two arms of immunity, ie Th1 and Th2

What damages gut flora?

A baby is mostly sterile in the mother's womb. As a baby passes through the birth canal during birth it is inoculated with microbes present in the mother. Babies are a micro-flora magnet over the next 2-3 years. The carers most in contact with babies, usually mothers and fathers, will have the strongest contribution to a baby's developing flora. Hence the inherent state of the carer's flora has a direct effect on the baby's developing flora which is carried through to adulthood and passed to the next generation.

It seems that in our modern world each generation is developing more pathogenic flora. Some of the factors which negatively impact our fragile internal flora are:

  • Bottle feeding and early weaning

  • Medications such as antibiotics and the oral contraceptive pill

  • Modern diet including processed foods high in starch, sugar, chemical additives and lacking in fermented foods which supply beneficial flora

  • Hormones produced from long term stress negatively affect gut flora

  • Chemicals from our modern environment including chlorine and other substances in our tap water, pesticides and synthetic fertilisers on our food

What goes wrong?

When you have more pathogenic flora than beneficial flora health suffers. It depends on your individual flora as to what disease develops and how your symptoms manifest. Some of the micro-organisms known to contribute to disease are StaphylococciStreptococciBacteroidsClostridia, yeasts and certain viruses and parasites. These micro-organisms establish themselves within the gut and their colonies start to consume nutrients and produce a wide range of toxins and by-products while compromising your digestive system. Effects of pathogenic flora include:

  • Toxicity: including alcohol and its by-product acetaldehyde, excess histamine and other amines, kryptopyrroles, clostridia neurotoxins, sulphites

  • Damage to the gut wall: many pathogens are capable of damaging the gut wall including Candida spp, parasites and some bacteria from the Spirochaetaceae family (SF). They do this by producing toxins which weaken the cell connections (Tight Junctions) and/or initiate inflammation or in the case of the SF burrow in between intestinal cells and weaken the lining of the gut wall. Some of these pathogens put down roots into the gut wall weakening its structure and increasing the permeability. Along with this the reduction in beneficial flora leads to compromised cell regeneration of the cells lining the gut wall

  • Reduced production of digestive enzymes: as an example candida produces toxins which supresses stomach acid production reducing the ability to digest protein. Damage to the gut wall hinders the production of a whole host of digestive enzymes leading to nutritional deficiencies and putrification of food

  • Nutritional deficiencies: B vitamins, minerals and amino acids

  • Incomplete digestion: for example when casein (from dairy) and gluten (from grains) are not digested completely the substances casomorphines and gluteomorphines are produced. As their name suggests these substances have drug-like effects and high levels have been detected in those with autism, depression and schizophrenia

  • Reduced ability to detoxify neurotransmitters and hormones: leading to chemical imbalances. Peptidases are responsible for breaking down used neurotransmitters and hormones as well as any mal-digested proteins (peptides). When protein digestion is inadequate the body is exposed to much more undigested protein (peptides) than the peptidases can handle. This in itself can effect brain function but also neurotransmitters and hormones are not dealt with and remain in circulation causing imbalances in brain chemistry

  • Inflammation: the immune system is not able to regulate inflammation well without beneficial flora and essential nutrients, plus toxins and undigested foods create a source of inflammation in the body and the brain

How does this affect the brain?

The brain needs a steady supply of essential nutrients and protection from disruptive toxins. If digestion and gut flora are faulty and there are toxins entering the blood stream and excessive inflammation the brain will not develop and function at optimum.

The brain also requires a very specific environment to function properly. It has a protective barrier to help maintain this environment, called the blood-brain barrier. When the blood brain barrier is intact there will be some protection from environmental toxins and from toxins within the body. This helps explain why some people with digestive problems may not have any brain symptoms. However, it is likely that if you have nutritional deficiencies and a leaky gut you will have some degree of leaky blood-brain barrier and the brain will be exposed to substances which disrupt its function.

There is a delicate balance of brain chemicals (hormones and neurotransmitters) influencing how the brain develops, how we feel and think and our very personality. When this system is interfered with by toxins and nutritional deficiencies, the balance is upset. The unique gut flora and digestive process of every individual brings about unique effects on the brain, manifestation of disease, personality traits and clarity of mind.

Including the gut flora as part of an individual is a new way to look at mental health and helps provide direction for the treatments we are so desperately seeking.


Conditions that have been successfully treated or managed with the GAPS treatment program include:


  • Adrenal gland disorders

  • Allergies

  • Anxiety disorders

  • Asthma

  • Autism spectrum disorders

  • Autoimmune disorders

  • Behavioural problems

  • Bipolar disorders

  • Candida yeast overgrowth

  • Celiac disease

  • Chronic diarrhoea

  • Chronic fatigue

  • Colic

  • Constipation

  • Cravings

  • Crohn's disease

  • Cystitis

  • Depression

  • Diabetes

  • Diverticulitis

  • Dyspraxia

  • Eczema

  • Eating disorders including fussy eaters

  • Gut dysbiosis

  • Heartburn including Gastroesophageal reflux disease (GERD)

  • Hyperactivity

  • Hypoglycaemia

  • Indigestion

  • Irritable bowel disorder

  • Leaky gut

  • Learning disorders

  • Lupus

  • Malnutrition

  • Menstrual and pre-menstrual disorders

  • Multiple sclerosis

  • Obsessive compulsive disorder

  • Osteoarthritis

  • Pyrrole disorder

  • Rheumatoid arthritis

  • Reflux

  • Schizophrenia

  • Seizures

  • Sinusitis

  • Skin disorders including psoriasis and eczema

  • Sleep disorders

  • Thyroid (low functioning)

  • Ulcerative colitis









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