Amanda Grant

The Bizarre Truth about Serotonin and Low Mood

Did you know that serotonin production plays a huge role in our mood? Did you also know that 80% of our serotonin is made in our gut.

Introduction to Serotonin and Low Mood


Low mood, wired yet tired, overwhelmed, anxious and feeling burnt out? How does Serotonin and low mood play a role?

Life. I believe in living your best life whilst you’re alive, after all, some say you only live once. However, life also gets in the way doesn’t it? Demanding careers, long hours, ambition, commuting, financial pressure, lack of work/life balance.

Kids, families, toxic relationships, debt, stress, lack of sleep, alcohol, smoking, infertility, eating on the go, weight gain, lack of motivation and, often unhappiness.

I’m Amanda. I’m a UK Registered naturopathically trained Nutritional Therapist and Certified Nutrigenomics practitioner and I’m here to help. Small easy steps will set you on the right path. Often we simply need help to know how to establish a clear plan, where to start and how to manage without taking on too much. I offer a non judgemental and practical approach to overwhelm. I have extensive biochemistry knowledge and can offer assistance with most issues that you may see your GP for. I can also interpret specific DNA test results and provide help on eating right for your genotype.

Today, we are going to talk about Serotonin, how it affects your mood and what you can do about it. 


Nutrient Synergy

Considering the human body runs on food, it is surprising that the relationship between major chronic diseases, diet, specific nutrients in food and our mental health, only began to be explored relatively recently, around 10 years ago. The majority of us now realise that unhealthy foods and an unhealthy diet, contribute to many common mental health issues. In fact, what is not as widely known, is that it is not only having a poor diet that contributes to mental health issues, but also a lack of specific nutrients contribute to these issues too, albeit in a different, but connected way.’Nutritional psychiatry’ and ‘Psychobiotic interventions’ aim to evoke a new approach to prevention [1].

Although (in the past) we began to realise the importance of nutrients in diet, research focused mostly on individualised specific nutrients, such as vitamins and minerals, rather than our overall diet. Whilst this research was hugely beneficial, it is only through exciting new research ‘Dietary pattern analysis’, that we have come to realise that the nutrients in food work best together, in synergy, rather than alone. This is unsurprising really, considering we use many foods in one meal. This new method is helping to ascertain disease and mortality risk [3].



  • Up to 90% of individuals consulting a GP nowadays, admit to feeling they have long term (chronic) stress. This keeps the body in a constant state of ‘fight or flight’.
  • Up to 80% of serotonin is made in the gut, which is why poor gut function is an issue. 

‘Psychoneuroimmunology’ has taught us that there is a link between long term (unbeneficial) stress, stressful events, adverse childhood events (ACE’s) and illness. We now know that illness is caused by stress hormones (corticosteroids) lowering and even suppressing our levels of immunity, which sadly leaves us wide open to conditions such as (but not limited to) autoimmune diseases, cancer, allergies, infection and FGD (functional gastrointestinal disorders) [4].



NHS UK states that ‘Half of all mental health problems have been established by the age of 14, rising to 75 per cent by age 24. The average wait for help, even 4 years ago, was 32 weeks plus. People with severe and prolonged mental illness are at risk of dying on average 15 to 20 years earlier than other people” [7].

If this is the case, it seems obvious that improvements in our diet need to be implemented in childhood. This could be further improved by eating for our “genotype“. 


So how can we help ourselves?


What is Serotonin?

Serotonin (5-HT) is both a hormone and a brain chemical (neurotransmitter), and is often described as the ‘happy hormone’.  

In fact, its main task in the body is to regulate brain function, prevent extremes of stress and anxiety and encourage both coping mechanisms and patience. 

Enough serotonin makes us capable, adaptable, personable, outgoing and positive, everything we want to be. 


Serotonin and low mood

A lack of serotonin can make us anxious, negative, troubled, neurotic, obsessive, unable to sleep well and has been implicated in psychiatric disorders [8]. Serotonin and low mood play a big role in the gut.

Up to 80% of serotonin is made in the gut, which is why poor gut function is an issue. 

Extended periods of stress, genetic factors, lack of specific nutrients in diet, poor gut absorbance of nutrients in food, and lack of specific amino acids can all contribute to low levels of serotonin and therefore, likelihood of low mood and mental health issues. 

It is claimed that in the future, genetic research will be able to give a clear indication of who will have a genetic predisposition to depression!

It is possible to raise serotonin levels within the brain through adequate exercise, which we would have had previously as hunter-gatherers, and through adequate exposure to bright light, which we would have had previously due to being outdoors, but now mostly do not have due to working indoors in artificial light. We can also improve serotonin levels through changes in thoughts that are induced by meditation and through optimal dietary levels of Tryptophan [9].



Tryptophan – The precursor to Serotonin

Tryptophan is both the precursor to Serotonin and an essential amino acid. This means we cannot produce this in the body and need to get it from within our diet. Low levels of protein within our diet can be a cause of insufficient levels of Tryptophan. Protein requirements are dependent largely on body weight but also change dependent on age, an individuals level and frequency of exercise, and in instances of severe infection, pregnancy, and after surgery [10]

Once consumed, Tryptophan converts to several bioactive compounds, one of which is Serotonin and another, the vitamin Niacin [11].

Adequate levels of tryptophan from diet and/or supplementation have been seen to reduce both anxiety, depression and irritability in individuals with neuropsychological disorders (or history of) with sub-optimal Tryptophan levels [12].


Tryptophan Rich Foods

Carbohydrate rich foods aid Tryptophans transport across the blood brain barrier. Tryptophan rich foods include:

  • Turkey
  • Fish
  • Eggs
  • Yoghurt
  • Chicken
  • Meat.

Serotonin is also needed for good sleep as Serotonin converts into Melatonin-the sleep hormone! [13].


Find out more


Get in touch for a free and informal chat to see how I can help you put yourself first and feel your best – Amanda Grant Registered naturopathically trained Nutritional Therapist and Certified Nutrigenomics practitioner.

Learn more about your genetics and nutrition our most recent podcast with Amanda. Find us on Spotify, Apple Podcasts, Google Podcasts and all other platforms – Evolution by Champ

Looking to save time? Tired of cook of cooking, washing and shopping? Champ is the first organic and personalised meal prep service in the UK

The Bizarre Truth about Serotonin and Low Mood

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