A mood is a feeling or a state of mind of a person at a point in time. You may feel happy, joy, uplifting or energetic at times. These are positive moods. However, feelings such as lonely, depress, worry, sad, tired, etc. are the opposite. Moods affect how one thinks, speaks, perceives the world, interacts with others, and even values oneself. The constant perpetuation of low moods is not healthy, and it leads to mood disorders, such as major depression.

Serotonin, a type of neurotransmitter in the brain, is a regulator of mood. Additionally, it is a very important neurochemical that affects many activities of the central nervous system, including sleep, mood, sexuality, aggression/impulsivity, biological rhythms, motor control, memory, learning, neuronal degeneration, and gastrointestinal motility and vasoconstriction [1]. Besides depression, low serotonin level can lead to many psychological and physical symptoms such as anxiety, aggression, insomnia, irritability, poor appetite, poor memory, etc. [2]   

Fortunately, food plays a role in the synthesis of serotonin and thus, the regulation of moods.  The essential ingredient required for the synthesis of serotonin is tryptophan, which is an essential amino acid found in many protein-based foods [3]. Traditionally, the dietician will recommend fish, meat, dairy, and egg as examples of high tryptophan foods. However, these are not food options for vegans. Fortunately, there are many plant-based sources of tryptophan as well. Here are five ways to boost your moods with plant-based foods.

1. Go for carbs

Interestingly, studies have shown that, even though the ingestion of carbohydrates does not increase the level of circulating tryptophan in blood, it can enhance the availability of tryptophan to the brain [4]. Hence, it is never a good idea to go for a low carb meal. You need the carbohydrates, from cereals and grains to boost the tryptophan conversion into serotonin in the brain.

2. Add more soy

Soy is known to help to reduce the risk of depression. Isoflavone, the phytoestrogen within soy, is also known to modulate the serotonin within the brain. It is not coincident, with a traditional diet rich in soy products, the depression rate is much lower in Japan [5]. So, make sure you add tofu, soymilk, or tempeh to your diet.

3. Eat your greens

Green vegetables, such as broccoli, spinach, mustard greens, etc. are also sources of tryptophan. Contents of tryptophan in green vegetables are even higher than most grains and beans [6]. Furthermore, vegetables also contain dietary fibres which feed the gut microbiome that play a role in regulating tryptophan metabolism in human [7].

4. Let’s go nuts

Nuts are an excellent addition to any diet as they are high in plant-based proteins and antioxidants. Specifically, walnut is known as food for the brain. In a randomized placebo-controlled, cross-over trial with sixty-four college students consuming walnuts for 6 weeks and placebo for another six weeks, consumption of walnut was found to improve mood beyond placebo significantly.

5. Don’t forget the fruits

Many fruits also contain high tryptophan levels and can increase the serotonin levels in the blood. Most important ones are banana, pineapple, avocado, grape, watermelon, and strawberry [8]. However, one concern is that the serotonin produced from fruits does not cross the blood-brain barrier. This can be remedied with the inclusion of carbohydrates in the diet, as mentioned previously [9].  

Conclusion

The five suggestions above are all plant-based elements of a complete diet, comprising of grains, legumes, nuts, and fruits. Hence, it is crucial for those who are on a plant-based diet to eat a variety of whole-food groups to boost the serotonin levels and maintain a good mood.

References

[1]        D. Marazziti, Understanding the role of serotonin in psychiatric diseases, F1000Research. 6 (2017) 180. doi:10.12688/f1000research.10094.1.

[2]        M.S. Whitney, A.M. Shemery, A.M. Yaw, L.J. Donovan, J.D. Glass, E.S. Deneris, Adult Brain Serotonin Deficiency Causes Hyperactivity, Circadian Disruption, and Elimination of Siestas, J. Neurosci. 36 (2016) 9828–9842. doi:10.1523/JNEUROSCI.1469-16.2016.

[3]        T.A. Jenkins, J.C.D. Nguyen, K.E. Polglaze, P.P. Bertrand, Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis, Nutrients. 8 (2016) 56. doi:10.3390/nu8010056.

[4]        D.M. Richard, M.A. Dawes, C.W. Mathias, A. Acheson, N. Hill-Kapturczak, D.M. Dougherty, L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications, Int. J. Tryptophan Res. 2 (2009) 45–60. https://www.ncbi.nlm.nih.gov/pubmed/20651948.

[5]        M. Messina, C. Gleason, Evaluation of the potential antidepressant effects of soybean isoflavones, Menopause. 23 (2016) 1348–1360. doi:10.1097/GME.0000000000000709.

[6]        M. Edelman, M. Colt, Nutrient Value of Leaf vs. Seed, Front. Chem. 4 (2016) 32. doi:10.3389/fchem.2016.00032.

[7]        A. Agus, J. Planchais, H. Sokol, Gut Microbiota Regulation of Tryptophan Metabolism in Health and Disease, Cell Host Microbe. 23 (2018) 716–724. doi:https://doi.org/10.1016/j.chom.2018.05.003.

[8]        J. Islam, H. Shirakawa, T.K. Nguyen, H. Aso, M. Komai, Simultaneous analysis of serotonin, tryptophan and tryptamine levels in common fresh fruits and vegetables in Japan using fluorescence HPLC, Food Biosci. 13 (2016) 56–59. doi:https://doi.org/10.1016/j.fbio.2015.12.006.

[9]        S.N. Young, How to increase serotonin in the human brain without drugs, J. Psychiatry Neurosci. 32 (2007) 394–399. https://www.ncbi.nlm.nih.gov/pubmed/18043762.