The connection between mood and food is becoming increasingly recognized, from the development of new fields like nutrition psychiatry, to new terms like the gut-brain axis. But how might this mood-food connection work on a biological level? And, how can we use food to improve our mood?
An example of a direct connection between mood and food is serotonin. Serotonin, a chemical messenger produced in our bodies, is commonly referred to as the ‘happy chemical’. In reality, it does much more than play a role in our happiness. Serotonin is vital to our health and well-being, stabilizing our mood, supporting learning, and regulating sleep and appetite. Even though serotonin is vital to brain function, the vast majority of serotonin (~95%) is produced in the gut by helpful gut bacteria. Gut serotonin levels are linked to irritable bowel syndrome (IBS), while low brain serotonin is linked to mood disorders like depression and anxiety. Many people with depression are prescribed medications that increase serotonin levels (like SSRIs - selective serotonin reuptake inhibitors) because they can lead to a better mood.
Okay, so serotonin is linked to mood. What does food have to do with it?
Short answer: Our diet can impact our serotonin levels.
While you can’t eat serotonin directly, you do eat the amino acid that serves as it’s foundation: tryptophan. In fact, research has found that people who switched to a low-tryptophan diet lowered their brain serotonin levels. Unfortunately, it turns out that depleting tryptophan through diet is an easier feat to manage than eating enough tryptophan to increase serotonin production.
This is largely because tryptophan has to compete with other amino acids to get 'let in' to the brain and then converted into serotonin. This conversion is also affected by carbohydrate availability, more carbs = more brain serotonin.
This relationship between carb intake and serotonin is one reason many people 'self medicate' by binging on carbs. But how can you raise your serotonin healthfully?
Serotonin Supporting Foods
1. Foods high in tryptophan:
Seeds, seed spices, and nuts: All contain high levels of tryptophan in a neat little health bundle. Seeds with especially high levels include sesame, sunflower, pumpkin, butternut squash, chia, and flax. Seed spices include mustard, fenugreek, and fennel, while high tryptophan nuts include pistachios, almonds, cashews, hazelnuts, and walnuts.
Salmon, poultry, eggs, milk, and soy: Also contain high levels of tryptophan, but because they contain high levels of other amino acids, eating them may cause the 'brain space' to be too competitive for tryptophan to get a spot. Even if they don't quickly boost your serotonin, tryptophan is an essential amino acid to eat to support serotonin production, because we cannot make tryptophan ourselves.
2. Carbohydrates to boost tryptophan and serotonin:
Whole grain rice, oatmeal, beans, sweet potato, a banana: While sweeter, starchier carbs are shown to lead to higher serotonin in the short term, you should still pick quality carb sources for consistent energy and a healthy gut microbiome. Poor quality calories can lead to worse mood, even if it may lead to a better mood initially. In a recent study referred to as the 'SMILES' trial, three months of cutting out refined sugars, overly processed foods, and ‘empty calories’ led to remission in over 30% of participants diagnosed with moderate to severe depression.
More research is needed to determine the best ways to increase serotonin through diet. However, serotonin levels can be increased through supplementing serotonin (5-hydroxytryptophan, 5-HTP), which has a history of being used for treatment of depression though results have been mixed. Tryptophan supplements have also been shown to raise brain serotonin levels. But raising serotonin too much can be a bad thing (it even has the potential to mess with other neurotransmitters), so if considering supplementation, start very small and definitely consult a health professional before use.
If depression or a low mood is something you or someone close to you struggles with, consider changing up your diet, and paying close attention to how the results feel. After all, our 'feelings' and our 'gut feelings' may be more connected than we think.