The most popular kid in brain school would have to be serotonin.
Serotonin has the ability to make people feel happy, warm and cuddly; earning itself the nickname: the Happiness Hormone. The chemical acts as a hormone and a neurotransmitter and is responsible for our cognition, reward, memory and learning.
Over the years, incredible work has gone into uncovering every little aspect of serotonin. Our desire for eternal happiness, as well as the need to alleviate conditions such as depression and anxiety, has driven us to find ways to replicate serotonin’s effects.
There are many ways to increase our serotonin levels. Anti-depressants are common and sometimes necessary. Non-medicinal methods include self-induced cognitive thinking, light therapy and exercise.
Of course, my favourite way would have to be with diet; a plant-based diet at that!
Serotonin is abundant in many fruits, vegetables and seeds including:
- Fruits: pineapple, banana, tomato, avocado
- Vegetables: eggplant
- Seeds: walnut
Unfortunately, since serotonin is unable to cross the blood-brain barrier, we’re unable to access the serotonin directly from these plant-foods. However, serotonin is made from converting tryptophan (an essential amino acid) through a series of reactions. Since tryptophan can cross the blood-brain barrier, we can indirectly increase the levels of serotonin this way.
But how much of an effect does a pre-cursor of serotonin actually have on the brain? Studies have demonstrated that low levels of tryptophan can cause psychological and cognitive impairments. Participants who received tryptophan-deficient diets were observed to be more depressed, anxious, irritable and tired.
On the other hand, high levels of dietary tryptophan has been suggested to increase moods, reduce stress and promote positive social behaviours.
Plant-foods that are high in tryptophan include:
- Nuts: cashews, walnuts, peanuts, almonds
- Seeds: sesame, pumpkin, sunflower, soybeans
- Grains: wheat, rice, corn
But not all tryptophan-rich foods are created equal. A factor that influences the level of serotonin derived from dietary tryptophan is the presence of other amino acids. One might think that since tryptophan is an amino acid itself, eating a protein-rich meal could technically increase tryptophan and thereby, serotonin levels.
However, a closer look at the interplay between these amino acids has found that eating a high-protein meal actually results in the shunting of tryptophan as other amino acids compete for access to the brain. This is where it gets interesting; when we eat a high-carb (low-protein) meal, non-tryptophan amino acids are diverted into the muscles allowing tryptophan easier access to the brain.
Therefore, a high-tryptophan, high-carb and low-protein food would be ideal to maximise tryptophan’s access to the brain. Fortunately, plant-foods are high in carbs compared to animal products. As with the list above, seeds generally have a lower protein content compared to nuts so eating sesame, pumpkin and sunflower seeds may be the best bioavailable sources of tryptophan!
What About Trypping on Tryptophan?
L-tryptophan is widely available as an over the counter supplement marketed to improve mood and sleep. Although possibly efficacious in treating psychiatric disorders such as depression, results from clinical trials have been widely inconsistent. As with any medication, the supplements have been associated with side effects such as heartburn, diarrhoea, drowsiness, dry mouth, muscle weakness and sexual problems. Furthermore, it can interact with a whole range of medications especially anti-depressants.
In 1989, L-tryptophan was associated with eosinophilia-myalgia syndrome. The condition is characterised by shortness of breath, muscle aches and fatigue. It affected 1500 individuals and resulted in over 30 deaths. The FDA placed a temporary ban on the sale of L-tryptophan following the outbreak and lifted it in 2005 when no new cases were seen. A review in 2012 suggested that the cause was contamination of certain batches that originated from one single manufacturer.
Personally, we don’t recommend L-tryptophan supplements for general use. We believe there are more natural ways of achieving similar effects without the risk of side effects and drug interactions. This stems largely from a holistic lifestyle. A whole-foods plant-based diet (with lots of tryptophan-rich foods!), exercising and good sleep have been associated with increased mood and brain functioning.
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