- Brain health is extremely important in allowing us to live long and happy lives – and it’s often when brain function is affected that ageing is accelerated, i.e. Alzheimer’s. We have known for a long time that our gut acts as a second nervous system that is capable of functioning without input from the brain.
Question: Do you agree, and do you have something to add here?
Gut is supplied by the enteric nervous system. As a part of the autonomic nervous system it is capable of operating independently of the brain and spinal cord, but does rely on innervation from the autonomic nervous system via the vagus nerve and spinal ganglia in healthy people. The neurons of the enteric nervous system control the motor functions of the system, such as peristalsis and segmentation which mix and propel the food through the gut, in addition to the secretion of gastrointestinal enzymes. These neurons communicate through many special signalling molecules – neurotransmitters which are similar to the central nervous system – brain.
- Nevertheless, the brain and the gut interact through the “brain-gut axis”, and what affects one can often affect the other. Here I am thinking of the way that serious nervousness or stress, before a race or before an exam, for example, can cause an upset stomach.
Question: Do you agree with this or have something to add in explanation? Also, would you say that excessive stress can cause gut disease?
Stress is a response of the central nervous system to environmental stimuli perceived as a threat to metabolic equilibrium called homeostasis. The stress response involves a complex mechanisms essential for survival, mediated by neurotransmitters (special molecules), and hormones from the enteric nervous system.
The stress response triggers the production of neurotransmitters and hormones from the brain-adrenal axis, sympathetic axis and brain-gut axis, and in this way it affects the intestinal immune system. The enteric nervous system communicates with central nervous system (brain-gut axis) via vagal and spinal nerves. It has been shown that stress may result in increased susceptibility to infection and intestinal inflammation.
- Our gut is home to about 100 trillion microorganisms, more than 400 known and diverse bacterial species. The resident bacteria in our gut have a major role to play in defending us against pathogenic microbes, as well as supplying important nutrients, and provides an estimated 75 percent of our immune system.
Question: Do you agree? What can we, as individuals do, to keep healthy levels of good bacteria in the gut? What can affect those levels, e.g. antibiotics? What should doctors advise patients to do when prescribing antibiotics so as to ensure that necessary, beneficial bacteria are replaced?
There is hardly a place on earth without bacteria. Human body is like a complex ecosystem containing trillions of bacteria and other microorganisms that inhabit all our surfaces; skin, mouth, sexual organs, and specially intestines. Human microbiota is a diverse and dynamic ecosystem, which has evolved in a complex relationship with its host. In its origin, it is vertically transferred from the mother during birth, established during the first year of life and during lifespan, horizontally transferred among relatives, friends or close community members. This micro-ecosystem protecting body against pathogens, metabolizing complex lipids and polysaccharides that otherwise would be inaccessible nutrients, neutralizing drugs and carcinogens, modulating intestinal motility, and maintaining internal balance.
Most people are familiar with the concept of probiotic foods, which are traditional fermented foods such as yogurt, kefir etc. These foods all contain beneficial bacteria important for housekeeping of our digestive tract and protecting from pathogenic (harmful) bacteria.
At some point, when e.g. antibiotics are prescribed for any bacterial infection such as sinus infection, pneumonia, urine infection, skin infection etc, they will kill not only the infection-causing bacteria but also the beneficial bacteria in our digestive system. As a result of this, some people experience diarrhea and indigestion during antibiotic treatment. The question comes if probiotics or certain food may prevent or alleviate these side effects? In the past, this has been a controversial question. Recent evidence showed that probiotics significantly reduce antibiotics-induced side effects. However, not everyone develops side effects during the antibiotic treatment, especially if the course of antibiotics is short and not repeated. In this case, probiotics rich food, such as plain yogurt or greek yogurt without extra sugar or additives is a good option how to keep the gut healthy. Those who benefit most from addition of probiotics during the antibiotic treatment are people on prolong or repeated course of antibiotics, or those with diarrhea-like side effects or yeast infection.
- Studies have shown that changes in gut flora can increase the rate at which we absorb fatty acids and carbs, and increase the storage of calories as fat. When gut flora are out of whack, we are prone to autoimmune conditions such as Type 1 diabetes, inflammatory bowel disease and Hashimoto’s. And in neuroscience, there is also recent evidence highlighting the important role of bacteria in the communication between the gut and the brain, indicating that mental illnesses such as autism, anxiety and depression may be linked to gut flora.
Question: Please comment on this – do you find this research interesting? Anything to add here?
It is now evident that the bidirectional signalling between the gastrointestinal tract and the brain, mainly through the vagus nerve, the so called “microbiota–gut–vagus–brain axis,” is vital for maintaining metabolic equilibrium – homeostasis. Recent studies showed that it may be also involved in the etiology of several metabolic and mental dysfunctions and disorders. It has been shown that microbiota within the gut can greatly influence many physiological parameters, including cognitive functions, such as learning, memory and decision making processes. In pediatric population, altered gut microbiota could be involved in the pathogenesis or progession of certain diseases like inflammatory bowel disease (IBD), celiac disease, asthma, allergy, and autism.
- It is thought that the following features of our modern lifestyle contribute directly to unhealthy gut flora: chronic stress; chronic infections; antibiotics and other medications; diets high in refined carbs, sugar and processed foods; diets low in fermentable fibres; dietary toxins like wheat and industrial seed oils that cause leaky gut.
Question: Do you agree? Please add anything that you feel is relevant, e.g. any advice on health or any examples of patients that you have helped.
A large number of studies have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota. The prebiotic effect of certain food has been shown to associate with modulation of the immune system. In infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, which improves stool quality, reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. Associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Dietary intake of particular food products with a prebiotic effect has been shown to increase Ca absorption as well as bone mineral density. Recent data support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. These support the hypothesis that gut microbiota composition may help to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. However, the role of such changes in these health benefits remains to be definitively proven.
Dr Andrea Rajnakova