Serotonin - Gut Health, Microbiome/Serotonin & Immune Part 3

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By Sally Pattison BAppSc, Adv. Dip. Nat, Adv. Dip. Nut

There is increasing evidence that the microbiome has an effect on the central nervous system and brain, affecting how we think, feel and act and on the development on neurological conditions.

Serotonin: The Brain-Gut Connection

Over 95% of the body’s serotonin, the 'happy hormone' is found in the gastro-intestinal (GI) tract, which has been called the body’s “second brain” because of its role in serotonin production and so many of the body’s vital functions.

Serotonin is a key player in the functioning of GI tract muscles, causing the contraction of our intestines, and triggering the gut nerves which signal pain, nausea, and other gut problems. As well, it influences the functioning of the cardiovascular, immune and renal systems. This amazing hormone also regulates aggression, appetite, cognition, mood, sexual behaviour and even sleep.

This neurotransmitter (chemical by which nerve cells communicate with each other or with muscles), serotonin is manufactured in our bodies from the amino acid tryptophan, which is derived from the food we eat. Diet, then, influences not only the state of our digestive system and overall physical health, it also has a profound impact on memory, mental clarity, mood, and even the foods we crave; these functions are all regulated by serotonin.

Scientists have shown that brain levels of serotonin are regulated by the amount of bacteria in the gut during early life. The research shows that normal adult brain function depends on the presence of gut microbes during development. Serotonin is altered in times of stress, anxiety and depression and most clinically effective antidepressant drugs work by targeting this neurochemical.

You may not be aware that you actually have two nervous systems:

  • Central nervous system, composed of your brain and spinal cord
  • Enteric nervous system, which is the intrinsic nervous system of your gastrointestinal tract

Both are created from identical tissue during foetal development—one part turns into your central nervous system while the other develops into your enteric nervous system. These two systems are connected via the vagus nerve, the tenth cranial nerve that runs from your brain stem down to your abdomen. It is now well established that the vagus nerve is the primary route your gut bacteria use to transmit information to your brain.

While many think of their brain as the organ in charge, your gut actually sends far more information to your brain than your brain sends to your gut... In other words, you've probably experienced the visceral sensation of ‘butterflies in your stomach’ when you're nervous, or had an upset stomach when you were very angry or stressed. The flip side is also true, in that problems in your gut can directly impact your mental health, leading to issues like anxiety and depression – it is a 2 way street.

Just as you have neurons in your brain, you also have neurons in your gut -- including neurons that produce neurotransmitters like serotonin. It’s quite possible that this might be one reason why antidepressants, which raise serotonin levels in your brain, are often ineffective in treating depression, whereas proper dietary changes often help.

Use gut bacteria to protect yourself against anxiety, depression, obesity and
a host of other mental health issues.

Diet Is Vital to Serotonin Production

So it is now shown that the microbiome has an effect not only on the metabolism but also affects brain function.

Nutrition is vital not only to our physical health; it’s necessary to a properly functioning digestive system capable of producing sufficient amounts of serotonin. A diet of “real food”– one rich in organic fruits and vegetables and free of trans fats, refined wheat and sugar – goes a long way toward preventing the build-up of toxins in the colon. And when it comes to serotonin production, the importance of raw foods for their nutrient value and serotonin-boosting properties cannot be over stated.

Tips for Ensuring Adequate Serotonin Levels

Eat foods rich in calcium, magnesium, and vitamin B to help with serotonin production.

Omega-3, omega-6, and gamma-linolenic acid (GLA) are required for serotonin production. GLA is found in black currant seed, borage, evening primrose and hemp seed oils.

Healthy carbohydrates and proteins help metabolize foods high in the agents responsible for serotonin production.

Avoid white flour and sugar carbohydrates. The boost they provide in serotonin levels is temporary and quickly followed by a crash.

Foods in which completely formed serotonin can be found include bananas, kiwis, pineapples, plantains, plums, tomatoes and walnuts.

Foods rich in tryptophan include almonds, bananas, beans, cheeses (particularly Cheddar and Swiss), chicken, eggs, fish (especially high-oil fish such as herring, mackerel, salmon, sardines, and tuna), milk, peanuts, soy foods, turkey and yoghurt.

Digestive enzymes and probiotic supplements can assist with full nutrient absorption from the above food sources, thereby increasing overall nutrient intake.

So if a twinge in your gut spikes your anxiety, you may want to consider getting your gut bacteria in balance with eating right, or taking the right probiotics.