Love Your Gut
Your Gut As Your Second Brain
PART 1: GUT BASICS Digestive system basics
The digestive system is a complex system and makes up one of the 11 organ systems of the body. The digestive system consists of:
- A group of organs: mouth, esophagus, stomach, small intestine, large intestine or colon, rectum and anus.
- Accessory organs & glands: salivary glands, liver, gallbladder and pancreas.
The digestive system’s function is controlled by the brain and nervous system. This system is responsible for the digestion and absorption of nutrients in the body and the excretion of toxins and wastes.
The gastrointestinal tract (from mouth to rectum) is commonly referred to as the gut. The gut is the most highly regenerative organ system in the human body and it regenerates its entire lining, every 5-7 days. Genetic and lifestyle factors (epigenetics) play a crucial role in gut health.
Genetics and Epigenetics
Human genetics is the study of genes, genetic variation and heredity in humans and the gut genes that we inherit from our parents may affect our gut health and function. The genes are found in the DNA, inside the nucleus of our cells that codes for all functions in the body.
Your DNA/genetic code can provide information on your susceptibility to gluten sensitivity, lactose tolerance, Inflammatory Bowel Disease (IBS), Leaky Gut Syndrome, probiotic genes, gut health genes, intestinal bacteria, histamine tolerance and gut inflammation.
It is very important to remember that genetics show your susceptibility to disease, it is not inevitable. There is hope, we are not victims of our genes!
The field known as epigenetics (epi=more important; genetics = than genes/genetic code) highlights the importance of factors that are more important than the genes, that can affect genetic expression, i.e. ‘switch’ genes on and off.
Epigenetic factors include lifestyle behaviours and neural pathways that have a direct effect on the environment surrounding our cells. The information then passes through the cell membrane (via channels or receptors), into the cell, and to the nucleus that then stimulates or inhibits specific genes. These factors are in our control and include: water, oxygen (your breathing), nutrients, thoughts, emotions, beliefs (Neuroplasticity vs Neurorigidity. New networks)!
The cell membrane is therefore the true brain of the cell, not the nucleus (as previously believed by scientists)!
The Microbiome
The microbiome is the full complement of the genes contained in all microbes (incl. bacteria, fungi, viruses, algae etc – the oldest form of life on earth). The microbiome is found outside (the skin) and inside (e.g. the gut) the body and also in soil, air, water and other living organisms. It is complementary to the human genome (all of our genes) and the genes in our microbiome outnumber the genes in our genome by about 100 to 1, meaning there is 100 times more genes in the microbiome of our body than inside all our cells.
Gut Flora and Microbiome Terms
Prebiotics is the non-digestible fibre substances that are fermented by the beneficial bacteria in the gut and is used as a source of fuel to help enhance gut flora health. Probiotics is the live microbes or micro-organisms (incl. bacteria) that can confer health benefits ranging from improved immunity to better brain function. We truly live in a symbiotic relationship with probiotics.
Postbiotics are the by-products of bacterial fermentation in the colon, incl. vitamins B & K, amino acids, antimicrobial peptides (that slows the growth of harmful bacteria).
Gut bacteria require a healthy gut lining to thrive and imbalances may lead to gut issues including indigestion (heartburn), food sensitivities, bloating, diarrhea, constipation, candida infections, IBS (irritable bowel syndrome), leaky gut syndrome, lazy bowel, stomach cramps, pain, weight gain, acne/skin problems, fatigue, sleep disturbances, autoimmune diseases, mood swings and depression.
The Gut-Brain Axis
The gut is known as the second brain due to the complex neural connections or pathways (neurons) running from the gut to the brain and vice versa. The gut alone is innervated by over 100 million neurons (nervous system cells). This connection between the gut and brain is known as the Gut-Brain Axis (GBA).
Cranial Nerve X, known as the Vagus Nerve, is critical for supplying parasympathetic (known as the rest and digest nervous system) information to visceral organs of the respiratory, digestive and urinary systems. It is important in the control of heart rate, bronchoconstriction and digestive processes. There are three ways that the GBA work together:
- Neurotransmitters & Serotonin – 90% of serotonin is produced in the gut. These neurochemicals regulate appetite, mood and stimulate the Vagus nerve that changes activity in many brain regions and affects hunger levels. (Glucagon-like peptide – GLP receptors in gut & posterior brain, heart, lungs, etc)
- Gut microbes stimulate immune cells that signal the brain. E.g. gut microbes can prompt immune cells to produce and release small proteins called cytokines – involved in immune response, inflammation
- Through metabolites, molecules produced by microbes in gut. Certain gut-microbe-derived fatty acids (e.g. butyrate, tyramine) send signals to cells that line the digestive tract, to increase serotonin production. The increased serotonin stimulates the vagus nerve or enter the bloodstream and travel to the brain.
Brain to Gut
Stress, anxiety, mental health challenges have physiological responses in the body, for e.g. affecting gut motility and function that may result in symptoms such as stomach pain and constipation.
Gut to Brain
The enteric nervous system (in the gut) produces neurotransmitters (incl. serotonin and metabolites) that may contribute to mental health incl. stress, anxiety and depression.
The Happiness Molecules and How to Hack Them
Here are some ways to practical hack your happiness molecules:
