Serotonin, also known as 5-HT (short for 5-hydroxytryptamine), is a neurotransmitter that occurs in our brain but also (a lot of it) in the wall of our intestines.
"Some people say" (think of Benjamin Zaphaniah saying that) ... that a human adult body contains, on average, about 10 mg of serotonin, i.e. 10,000 µg (micrograms).
Serotonin influences our behaviour, also our eating behaviour (like "stress/emotional eating"), our sleep quality, and also the moving of STUFF though our intestines.
Serotonin is made from the (essential) amino acid tryptophan (to put it simply). And serotonin is one of the precursors from which melatonin (the "sleep hormone"; not to be confused with melanin) is made.
Interestingly (for people like you), foods also contain serotonin. For example some fruit, vegetables, and nuts are quite rich in serotonin.
It has been reported that green (unripe) bananas contain about (very roughly) 10 or 20 µg of serotonin per gram (
Adao & Gloria 2005). So, that let's say, one small
banana weighs about 100 g, or one massive banana would weight about 200 g. Consequently, that would be 1,000 to 2,000 µg of serotonin in the small green banana and 2,000 to 4,000 µg of serotonin in the massively huge green banana (
Briguglio et al. 2018).
Chili peppers and paprika, tomatoes, pineapples, plums, passion fruit, papaya, and kiwi fruit also seem to contain some serotonin. Tomatoes even contain quite large amounts apparently: more than 200 µg/g (
Huang & Mazza 2011).
But how much in nuts?
Serotonin content of nuts |
Nuts | Serotonin (µg/g) | Country | Reference |
Almonds, raw | 0.2 | Turkey | Yilmaz et al. 2019 |
Almonds, roasted | 0.1 | Turkey | Yilmaz et al. 2019 |
Brazil nuts, roasted | 3.8 | Turkey | Yilmaz et al. 2019 |
Black walnuts (Juglans nigra) | 304 | USA | Feldman & Lee 1985 |
Butternuts (Juglans cinerea) | 398 | USA | Feldman & Lee 1985 |
Cashew nuts, raw | 1.3 | Turkey | Yilmaz et al. 2019 |
Cashew nuts, roasted | 0.8 | Turkey | Yilmaz et al. 2019 |
Chestnuts, raw | 0.5 | Turkey | Yilmaz et al. 2019 |
Coconut (dried), raw | 0 | Turkey | Yilmaz et al. 2019 |
Hazelnuts, raw | 1.7 | Turkey | Tas et al. 2019 |
Hazelnuts, roasted | 1.0 | Turkey | Tas et al. 2019 |
Hazelnuts, raw | 0.5 | Turkey | Yilmaz et al. 2019 |
Hazelnuts, roasted | 0.2 | Turkey | Yilmaz et al. 2019 |
Hazelnuts | 3.4 | Spain | Lavizzari et al. 2006 |
Hickory nuts (shagbark, Caraya ovata) | 143 | USA | Feldman & Lee 1985 |
Hickory nuts (mockernut, Caraya tomentosa) | 67 | USA | Feldman & Lee 1985 |
Hickory nuts (pignuts, Caraya ovalis) | 25 | USA | Feldman & Lee 1985 |
Macadamia nuts, roasted | 0 | Turkey | Yilmaz et al. 2019 |
Peanuts, raw | 0 | Turkey | Yilmaz et al. 2019 |
Peanuts, roasted | 0 | Turkey | Yilmaz et al. 2019 |
Pecan nuts, raw | 13.6 | Turkey | Yilmaz et al. 2019 |
Pecan nuts, roasted | 15.3 | Turkey | Yilmaz et al. 2019 |
Pecan nuts | 29 | USA | Feldman & Lee 1985 |
Pine nuts, raw | 0.1 | Turkey | Yilmaz et al. 2019 |
Pistachios, raw | 0.5 | Turkey | Yilmaz et al. 2019 |
Pistachios, roasted | 0.4 | Turkey | Yilmaz et al. 2019 |
Walnuts, raw | 155.0 | Turkey | Yilmaz et al. 2019 |
Walnuts | 280 | Netherlands | Kema et al. 1992 |
Walnuts | 87 | USA | Feldman & Lee 1985 |
Walnuts (cultivar: Hartley) | 0.01 | Spain | Tapia et al. 2013 |
Walnuts (cultivar: Chandler) | 0.01 | Spain | Tapia et al. 2013 |
Walnuts (cultivar: Howard) | 0.01 | Spain | Tapia et al. 2013 |
Walnuts (cultivar: Serr) | 0.03 | Spain | Tapia et al. 2013 |
Walnuts | ~250 | Germany | Kirberger & Braun 1961 |
The relevance of serotonin in foods is currently uncertain. Nuts are also relatively high in tryptophan, which the body can convert to serotonin. The tryptophan levels in nuts are much higher than the serotonin levels (
Tas el al. 2019) - and the typtophan content may be much more relevant in terms of nutrition and health.
Side note: Some have hypothesized that a large percentage of the serotonin in blood comes from the bacteria in our intestine. However, this is based on (cruel) mouse experiments: "The gut microbiome is a potent mediator of gut-derived serotonin synthesis, as approximately 90% of total body serotonin is synthesized from enterochromaffin cells in the linings of the gut wall. This peripheral source of serotonin is itself an important regular of glucose homeostasis." (
Teo et al. 2022)
References
Adao, R. (2005). Bioactive amines and carbohydrate changes during ripening of "Prata" banana (Musa acuminata x M. balbisiana).
Food Chemistry,
90(4), 705–711.
https://doi.org/10.1016/j.foodchem.2004.05.020Briguglio, M., Dell’Osso, B., Panzica, G., Malgaroli, A., Banfi, G., Zanaboni Dina, C., Galentino, R., & Porta, M. (2018). Dietary Neurotransmitters: A Narrative Review on Current Knowledge.
Nutrients,
10(5), 591.
https://doi.org/10.3390/nu10050591Feldman, J. M., & Lee, E. M. (1985). Serotonin content of foods: Effect on urinary excretion of 5-hydroxyindoleacetic acid.
The American Journal of Clinical Nutrition,
42(4), 639–643.
https://doi.org/10.1093/ajcn/42.4.639Huang, X., & Mazza, G. (2011). Application of LC and LC-MS to the analysis of melatonin and serotonin in edible plants.
Critical Reviews in Food Science and Nutrition,
51(4), 269–284.
https://doi.org/10.1080/10408398.2010.529193Kema, I. P., Schellings, A. M., Meiborg, G., Hoppenbrouwers, C. J., & Muskiet, F. A. (1992). Influence of a serotonin- and dopamine-rich diet on platelet serotonin content and urinary excretion of biogenic amines and their metabolites. Clinical Chemistry, 38(9), 1730–1736.
Kirberger, E., & Braun, L. (1961a). Über das Vorkommen von 5-hydroxytryptamin in der Walnus (Juglans regia)
[On the occurrence of 5-hydroxytryptamine in the walnut (Juglans regia)]. Biochimica et Biophysica Acta, 49(2), 391–393. https://doi.org/10.1016/0006-3002(61)90141-XLavizzari, T., Teresa Veciana-Nogués, M., Bover-Cid, S., Mariné-Font, A., & Carmen Vidal-Carou, M. (2006). Improved method for the determination of biogenic amines and polyamines in vegetable products by ion-pair high-performance liquid chromatography.
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https://doi.org/10.1016/j.chroma.2006.06.090Tapia, M. I., Sánchez-Morgado, J. R., García-Parra, J., Ramírez, R., Hernández, T., & González-Gómez, D. (2013). Comparative study of the nutritional and bioactive compounds content of four walnut (Juglans regia L.) cultivars.
Journal of Food Composition and Analysis,
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https://doi.org/10.1016/j.jfca.2013.06.004Taş, N. G., Yılmaz, C., & Gökmen, V. (2019). Investigation of serotonin, free and protein-bound tryptophan in Turkish hazelnut varieties and effect of roasting on serotonin content.
Food Research International (Ottawa, Ont.),
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https://doi.org/10.1016/j.foodres.2018.11.051Yılmaz, C., Taş, N. G., Kocadağlı, T., & Gökmen, V. (2019). Determination of serotonin in nuts and nut containing products by liquid chromatography tandem mass spectrometry.
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https://doi.org/10.1016/j.foodchem.2018.08.064
