Recently there have been many speculations about the connection between what we eat and how we mentally feel aka diet and mental health. And even though, I am all for healthy eating, "a perfect diet for mental health" is still at its infancy (sigh!). Let's talk about some recent findings (or not so recent) and what we can take from them to optimize or help our mental health.
Sweet lies (sugar and mental health)
Do you like sugary foods? What about when you are anxious or stressed out?
I know that many of us grew up believing that sweet foods can help us deal with stress. In fact, researchers from the University of Cincinnati have found that eating or drinking sweets may decrease the production of the stress-related hormone glucocorticoid, which has been linked to obesity and decreased immune response1. Despite the possible "quick fix", studies also show that high blood sugar may play a role in the development or clinical progression of anxiety, depressive symptoms and measurable changes in the brain2.
So, personally I try to consume chocolate in moderation and replace things that contain refined sugar with fruit (no, I am not perfect, of course!).
What about fat?
I think we have all been in the situation when a doughnut sounded like the best medicine. And it might be, in the moment, when we are eating it. However, high fat/high sugar western diet is associated with cognitive impairments (particularly memory impairments) and increased anxiety.
Some studies mention that high blood sugar comes as a result of consuming a high-fat diet that often leads to increased body weight. Even antidepressants weren’t as effective in mice fed a high-fat diet as they could have been.
Researchers concluded that the normalization of metabolic parameters (losing weight, lowering blood sugar) may help to achieve remission, particularly in depressed patients with type 2 diabetes3.
I stick to low-fat diet, partially because of my stomach issues. But if it is beneficial to my mental health long term as well - I am all for it, of course.
Fermented foods and gut health
You have probably heard that gut microbiota plays an important role in the responses to stress and affective disorders, including anxiety, depression and cognition.
Therefore, research suggests that probiotics can have an anti-anxiety effect. Interestingly enough, fermented food consumption was associated with fewer symptoms of social anxiety4.
High fiber and Mediterranean diets are also associated with a reduced likelihood of depression due to diverse gut microbiota. Even though it is yet to be found how exactly gut microbiota and mental health are connected, it is clear it won't hurt to eat more veggies and fruit.
In one of my posts I briefly mentioned GABA (Gamma aminobutyric acid). GABA is an important amino acid that works as a neurotransmitter in our brain. It produces a calming effect by attaching to a special protein (known as GABA receptor) in our brain.
A wide range of traditional foods produced by microbial fermentation contain GABA, however it has long been thought that GABA is unable to cross the blood–brain barrier (BBB)5. Again, it won't probably hurt (if you are not intolerant) to add some sauerkraut to your favorite meals for at least its probiotic properties and see how you feel.
Very little is known about the specific dietary components that provide mental health benefit.
Research shows that the detrimental behavioral, cognitive and neurochemical effects of stressed adolescent rats were normalized by diets enriched in omega-3 polyunsaturated fatty acids (ALA, DHA and EPA), eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid and vitamin A6.
ALA is present in plant oils, such as flaxseed, soybean and canola oils. You can find DHA and EPA in fish, fish oils, and krill oils. Some studies show though that dietary EPA and DHA intake failed to compensate for the harmful effects of arachidonic acid, cholesterol, and saturated fat that are found in fish. Therefore, fish consumption isn't recommended by plant-based doctors.
An inetersting fact, though, that DHA and EPA are originally synthesized by microalgae, not by the fish. When fish consume phytoplankton that consumed microalgae, they accumulate the omega-3s in their tissues7.
One study indicated that increasing consumption of foods rich in tryptophan (the amino acid our body uses to produce serotonin, a neurotransmitter largely responsible for feelings of happiness and well-being) may affect depression and mood scores, while consuming less dietary tryptophan resulted in more irritability and anxiety8.
Plant-based sources of tryptophan are leafy greens, sunflower seeds, soybeans, pumpkin seeds, mushrooms, broccoli, and peas. Even though turkey (as we all know) also contains tryptophan, the body can have a difficult time converting it to serotonin. "Competition" from other amino acids prevents tryptophan from entering the brain, resulting in low serotonin production9.
Foods rich in natural compounds called polyphenols seem to be good for our well-being as well. Those guys affect a wide range of mechanisms in the brain that can assist in the maintenance of cognitive and mental health.
Foods containing higher amounts of polyphenols that may improve our mood are apples, grapes, berries, kale, onion and green tea.
It seems very intuitive that brain function, just like any other part of our body, depends on a proper nutrition. However, there are still not enough studies that would demonstrate how and why certain nutrients and diets may cause mental health issues, benefit our mental health, and even work as a remedy. It doesn’t mean though that it doesn’t matter.
So as many of us probably already know, eating more fruits and vegetables is good for our overall health. But it has also been discovered that increased consumption of these foods may increase feelings of happiness and improve mental health.
However, the role that foods play in individual’s mental health will most likely depend on previous dietary experiences and maternal diet during and prior to pregnancy as well as stress experience and some other factors, that were discussed here.
What is recommended by doctors is that we "start paying attention to how eating different foods makes us feel - not just in the moment, but the next day"10.
There is so much to learn. Those were just a few bits of information that I was able to talk about in this blog post. I hope you enjoyed it though. Share it if you did, or simply leave a comment. Until next time on Pillows&Trees.
1 University of Cincinnati. "Sweet Snacks Could Be Best Medicine For Stress." ScienceDaily. ScienceDaily, 28 November 2005. <www.sciencedaily.com/releases/2005/11/051128011306.htm>
2 Murphy, M., & Mercer, J. G. (2013). Diet-regulated anxiety. International journal of endocrinology, 2013, 701967. https://doi.org/10.1155/2013/701967
3 Wiley. "High-fat diet may cause changes in brain that lead to anxiety, depression." ScienceDaily. ScienceDaily, 19 October 2015. <www.sciencedaily.com/releases/2015/10/151019123204.htm>
4 Hilimire MR, DeVylder JE, Forestell CA. Fermented foods, neuroticism, and social anxiety: An interaction model. Psychiatry Res. 2015;228(2):203-208. doi:10.1016/j.psychres.2015.04.023
5 Dhakal, R., Bajpai, V. K., & Baek, K. H. (2012). Production of gaba (γ - Aminobutyric acid) by microorganisms: a review. Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 43(4), 1230–1241. https://doi.org/10.1590/S1517-83822012000400001
6 Roger A.H. Adan, Eline M.van der Beek, Jan K.Buitelaar, John F.Cryan, Johannes Hebebrand, Suzanne Higgs, HarrietSchellekensg, Suzanne L.Dicksonb, Nutritional psychiatry: Towards improving mental health by what you eat, review, December 2019, <https://www.sciencedirect.com/science/article/pii/S0924977X19317237>
7 Omega-3 Fatty Acids, fact sheet for health professionals, October 2019, <https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/>
8 Lindseth, G., Helland, B., & Caspers, J. (2015). The effects of dietary tryptophan on affective disorders. Archives of psychiatric nursing, 29(2), 102–107. https://doi.org/10.1016/j.apnu.2014.11.008
9 Physicians Commitee, Food and Mood: Eating Plants to Fight the Blues, article, June 2015, <https://www.pcrm.org/sites/default/files/2018-09/Food-and-Mood.pdf>
10 Eva Selhub MD, Nutritional psychiatry: Your brain on food, article, November 2015, <https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626>