Serotonin is famously referred to as a ‘happy chemical’* in our brain due to its involvement in sustaining well-being. However, serotonin is incorporated in so many different functions all over the body, including digestion, cardiovascular health and bladder control, among others. Lack of serotonin is associated with the development of numerous health conditions, such as anxiety, depression, mood and sleep disorders, reinforcing the importance of sustaining its normal levels. In this article, we will talk about what serotonin is and why it is important. Then, we will cover the foods that could naturally boost your serotonin levels. We will also talk about alternative ways to boost serotonin levels.
*Disclaimer: serotonin should not be confused with dopamine. Both neurotransmitters are associated with mental well-being; however, they have different functions.
Serotonin, also called 5-hydroxytryptamine (5-HT), is a monoamine (meaning it is derived from an amino acid) neurotransmitter that carries signals between the cells in the brain and throughout the body.1,2,3 A neurotransmitter is a messenger that sends and relays signals in the brain.
Serotonin is synthesised with the help of an essential amino acid called tryptophan. Tryptophan is converted into 5-hydroxytryptophan (5-HTP), which is then converted into serotonin (5-HT).9,18 Tryptophan is the sole precursor of serotonin and can only be obtained through protein-based foods, including meat, dairy and seeds. Once tryptophan is consumed, it is metabolically transformed into bioactive metabolites: melatonin, serotonin, tryptamine, and kynurenine, among others. Overall, tryptophan is necessary for synthesising serotonin all over the body. 5,18
Serotonin in the central nervous system is primarily produced in the brain region called raphe nuclei, situated in the midline brainstem. These serotonin-producing neurons then project throughout the brain and supply serotonin to the rest of the central nervous system. Through such a diffuse network, serotonin modulates mood, cognition, sleep and temperature.1,2,3 However, despite serotonin being primarily recognised for its brain involvement, only 10% of serotonin is actually made within the brain, and most of it (90%) is secreted from the gastrointestinal tract. Therefore, serotonin also has functional importance in controlling bowel movements, initiating nausea and overall digestive performance.7,8,13,16
Serotonin has been implicated in regulating emotional states, and much research has looked into developing serotonin analogues. These can then be used in the form of drugs to either support or change serotonin function and potentially relieve the symptoms of multiple disorders, including anxiety and depression.17 Research suggests that low serotonin levels are associated with mood disorders, depression and anxiety. However, this relationship is very complex, and simply having low serotonin levels does not cause depression or anxiety. Instead, low serotonin levels, along with other physiological changes and precursors, contribute to multiple health issues, including sleep disturbances, digestive problems and emotional distress. Therefore, it is essential to sustain an adequate level of serotonin.
There are two potential reasons for having low serotonin levels: insufficient serotonin production or inefficient use of serotonin. First, if your body is unable to produce sufficient serotonin, it might be due to vitamin or nutritional deficiencies. In the second case, your body might be unable to efficiently use serotonin due to the lack or poor function of existing serotonin receptors. You can do several things to sustain your serotonin levels, including pharmacologic and nonpharmacologic ways. Due to the more appealing nature of nonpharmacologic interventions, let's look at how we can naturally boost our serotonin levels.
Foods that boost serotonin
The research suggests that increasing the intake of foods rich in tryptophan can boost one’s serotonin levels. As tryptophan is a serotonin precursor, taking food with more tryptophan can potentially support the process of serotonin synthesis.17 You can check the foods with high tryptophan content using the following tool.
Top 10 tryptophan-rich foods are:
- Poultry (e.g., turkey)
Poultry products such as turkey and chicken are known for being protein-rich foods. However, they are also rich in amino acids, including tryptophan, which is necessary for your body to keep producing serotonin. For instance, a cooked 6 oz (170 grams) chicken breast has 687 milligrams of tryptophan, 245% of the recommended daily intake.
- Red meat (e.g., lamb, pork)
As in poultry, red meat is rich in protein and tryptophan amino acid, which boosts serotonin synthesis similarly. Pork and beef have a high tryptophan content, and 6 oz (170 grams) lamb shoulder can have as much as 706 milligrams of tryptophan, making 252% of the recommended daily intake. Furthermore, red meat is rich in vitamin D, B12, zinc and iron.
Eggs are generally rich in proteins, lipids, minerals and vitamins, including vitamin B12, vitamin A, choline, and zinc. Most importantly, eggs contain protein that can significantly boost your levels of tryptophan in plasma. In addition, it is crucial to include yolks when consuming eggs, as they are rich in many nutrients with health benefits and antioxidant properties.15
- Cheese and other dairy products
Cheese, as well as other dairy products, are rich in tryptophan amino acid which is used to synthesise serotonin and melatonin. Melatonin is essential for regulation of one’s circadian rhythm (natural wake-sleep cycle) and studies suggest that a well-balanced diet incorporating dairy products can boost your quality of sleep.10,11 Furthermore, research suggests that higher dairy intake is associated with better mood, which is mediated by boost in serotonin synthesis.
- Soy products
Research suggests that soy products, such as soy milk, soya sauce and tofu, can be rich in tryptophan. Furthermore, researchers have been successful at genetically engineering soy products with higher tryptophan content over time. For instance, transgenic soybean plants have been found to have a very high tryptophan concentration compared to non-transgenic ones. In fact, one scoop of soy protein powder can have up to 116% of tryptophan's recommended daily intake. Over the past decade, soy products have become more available, and people who prefer not to consume dairy have an excellent option of consuming soy products and getting the necessary tryptophan intake.
- Fish (e.g. salmon)
Salmon and other types of fish are an essential part of a diet due to their numerous nutritional benefits. Firstly, fish has a high concentration of omega-3 fatty acids known for their anti-inflammatory properties. Secondly, it is rich in vitamins B6 and B12, which are implicated in the healthy functioning of the adrenal glands and the central nervous system. Thirdly, it is an excellent source of tryptophan. According to the My Food Data, a 6 oz (170 grams) salmon fillet has 570 milligrams of tryptophan, which is 203% of recommended daily intake.
- Nuts and seeds
Sesame, pistachios, cashews, squash and pumpkin seeds, and other nuts and seeds have high tryptophan content. For instance, 28 grams of squash and pumpkin seeds have 164 milligrams of tryptophan, equating to 58% of recommended daily intake. Furthermore, nuts and seeds are usually rich in other nutrients, such as zinc, calcium, and omega-3 fatty acids. Most importantly, nuts and seeds can be incorporated into any diet or meal and can be a valuable source of tryptophan.
Oatmeal is known for its high carbohydrate content, but it also has some tryptophan. Although oatmeal is not as rich in tryptophan as poultry or red meat, it can be a great meal choice for breakfast, as one cup of cooked oats can have up to 147 milligrams of tryptophan. 18
Recent evidence shows the potential of pineapple to boost your serotonin levels due to being tryptophan-rich, with ten milligrams of tryptophan per cup.14
Numerous studies show that beans and lentils are rich in tryptophan. However, the tryptophan content highly depends on the type of beans and lentils. Lupins and soya beans showed the highest tryptophan content, followed by other legumes.
Other ways to boost serotonin
There are other ways to boost your serotonin levels other than changing your diet.
- Engaging in regular exercise: research shows numerous benefits of regular exercise on the cognitive, neuropsychological and neurochemical functions. Exercise induces fast changes in the serotonin system and increases central serotonergic levels. Animal studies showed that acute exercise could improve one’s cognitive functioning, with the intensity being significantly positively correlated with plasma serotonin levels. Therefore, incorporating exercise into your lifestyle could be highly beneficial to boost your serotonin levels1,21
- Taking probiotics: many people worldwide are taking probiotics, which are living microorganisms (usually in the form of yoghurt) with numerous health benefits. Multiple studies suggest that the consumption of probiotics increases plasma levels of tryptophan and decreases the metabolite which breaks down serotonin (5-hydroxyindoleacetic acid). The findings indicate that probiotics can have a positive effect on the body by regulating levels of serotonin. This can have further benefits in mood disorders20,21
- Enjoying the sun: it is thought that serotonin levels in our body alternate depending on the seasonal variation in mood and behaviour. Previous studies showed that the lowest serotonin levels in people were observed in winter, and the levels were highly correlated with the amount of sun exposure one was getting12,21
Serotonin is an important neurotransmitter and a hormone. It has functional importance in the central nervous system and the periphery. Low serotonin levels are implicated in numerous health issues, reinforcing the importance of sustaining adequate serotonin levels in your body. Natural ways of maintaining serotonin levels include consuming tryptophan-rich products, exercising regularly, taking probiotics and enjoying the sun.
- Basso JC, Suzuki WA. The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review. BPL. 2017 Mar 28;2(2):127–52. Available from:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928534/
- Berger M, Gray JA, Roth BL. The Expanded Biology of Serotonin. Annu Rev Med. 2009 Feb 1;60(1):355–66. Available from: https://pubmed.ncbi.nlm.nih.gov/19630576/
- Carhart-Harris R, Nutt D. Serotonin and brain function: a tale of two receptors. J Psychopharmacol. 2017 Sep;31(9):1091–120. Available from: https://pubmed.ncbi.nlm.nih.gov/28858536/
- Comai S, Bertazzo A, Bailoni L, Zancato M, Costa CVL, Allegri G. Protein and non-protein (free and protein-bound) tryptophan in legume seeds. Food Chemistry. 2007 Jan;103(2):657–61. Available from: https://www.researchgate.net/publication/223721904_Protein_and_non-protein_free_and_protein-bound_tryptophan_in_legume_seeds
- Davidson M, Rashidi N, Nurgali K, Apostolopoulos V. The Role of Tryptophan Metabolites in Neuropsychiatric Disorders. IJMS. 2022 Sep 1;23(17):9968. Available from: https://pubmed.ncbi.nlm.nih.gov/36077360/
- Friedman M. Analysis, Nutrition, and Health Benefits of Tryptophan. Int JRes. 2018 Jan;11:117864691880228. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158605/
- Fu Y, Liang X, Li D, Gao H, Wang Y, Li W, et al. Effect of Dietary Tryptophan on Growth, Intestinal Microbiota, and Intestinal Gene Expression in an Improved Triploid Crucian Carp. Front Nutr. 2021 Jun 17;8:676035. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8247481/
- Jenkins T, Nguyen J, Polglaze K, Bertrand P. Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis. Nutrients. 2016 Jan 20;8(1):56. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728667/
- Jones LA, Sun EW, Martin AM, Keating DJ. The ever-changing roles of serotonin. The International Journal of Biochemistry & Cell Biology. 2020 Aug;125:105776. Available from: https://pubmed.ncbi.nlm.nih.gov/32479926/
- Kalantari N, Doaei S, Gordali M, Rahimzadeh G, Gholamalizadeh M. The Association between Dairy Intake, Simple Sugars and Body Mass Index with Expression and Extent of Anger in Female Students . Iran J Psychiatry. 2016 Jan;11(1):43–50. Available from: https://pubmed.ncbi.nlm.nih.gov/27252768/
- Komada Y, Okajima I, Kuwata T. The Effects of Milk and Dairy Products on Sleep: A Systematic Review. IJERPH. 2020 Dec 16;17(24):9440. Available from: https://pubmed.ncbi.nlm.nih.gov/33339284/
- Lambert G, Reid C, Kaye D, Jennings G, Esler M. Effect of sunlight and season on serotonin turnover in the brain. The Lancet. 2002 Dec;360(9348):1840–2. Available from: https://pubmed.ncbi.nlm.nih.gov/12480364/
- Lv J, Liu F. The Role of Serotonin beyond the Central Nervous System during Embryogenesis. Front Cell Neurosci [Internet]. 2017 Mar 13 [cited 2022 Nov 28];11. Available from: http://journal.frontiersin.org/article/10.3389/fncel.2017.00074/full
- Purnawati S, Putu Wrasiati L, Bagus Jaya Lesmana C. The Potency of Tryptophan Compound in a Combination of Bali Green Banana ( Musa acuminata Colla) and Java Pineapple ( Ananas comosus L. Merr) Extract and Its Opportunities as a Suppressive Self-behavior from Natural Ingredient. Setiawan J, Sarmin, Jenie IM, Ari Wibowo R, Arif M, Tarigan R, et al., editors. BIO Web Conf. 2022;49:03005. Available from: https://www.researchgate.net/publication/361782219_The_Potency_of_Tryptophan_Compound_in_a_Combination_of_Bali_Green_Banana_Musa_acuminata_Colla_and_Java_Pineapple_Ananas_comosus_L_Merr_Extract_and_Its_Opportunities_as_a_Suppressive_Self-behavior_from
- Réhault-Godbert S, Guyot N, Nys Y. The Golden Egg: Nutritional Value, Bioactivities, and Emerging Benefits for Human Health. Nutrients. 2019 Mar 22;11(3):684. Available from: https://pubmed.ncbi.nlm.nih.gov/30909449/
- Reigstad CS, Salmonson CE, Iii JFR, Strazewski JH, Linden DR, Sonnenburg JL, et al. Gut microbes promote colonic serotonin production through an effect of short‐chain fatty acids on enterochromaffin cells. FASEB j. 2015 Apr;29(4):1395–403. Available from: https://pubmed.ncbi.nlm.nih.gov/25550456/
- Reuter M, Zamoscik V, Plieger T, Bravo R, Ugartemendia L, Rodriguez AB, et al. Tryptophan-rich diet is negatively associated with depression and positively linked to social cognition. Nutrition Research. 2021 Jan;85:14–20. Available from: https://pubmed.ncbi.nlm.nih.gov/33383299/
- Richard DM, Dawes MA, Mathias CW, Acheson A, Hill-Kapturczak N, Dougherty DM. L -Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. Int JTryptophanRes. 2009 Jan;2:IJTR.S2129. Available from:
- Stewart RM, Wong JWY, Mahfouda S, Morandini HAE, Rao P, Runions KC, et al. Acute Tryptophan Depletion Moja-De: A Method to Study Central Nervous Serotonin Function in Children and Adolescents. Front Psychiatry. 2020 Mar 6;10:1007. Available from: https://pubmed.ncbi.nlm.nih.gov/32210845/
- Wallace CJK, Milev R. The effects of probiotics on depressive symptoms in humans: a systematic review. Ann Gen Psychiatry. 2017 Dec;16(1):14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319175/
- Young SN. How to increase serotonin in the human brain without drugs. J Psychiatry Neurosci. 2007 Nov;32(6):394–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2077351/