The Food-Mood Connection

by Kate Daugherty, MS, Functional Nutritionist

When we think about our diet, so much emphasis is on benefits like weight loss, blood sugar balance, correcting immune dysfunction, or limiting inflammation. Yes, absolutely, these things deserve our focus— but how and what you eat can massively impact your mental health as well.

Following a nutrition plan can make you happier, more content, more optimistic.. and just make you feel GOOD. That alone is a powerful motivator for dietary change.

FOOD and MOOD

If you’ve turned to food for comfort OR if you’ve noticed that you’re feeling a little “off” after eating junk food (read: highly processed foods), you’ve already experienced the food-mood connection. Even if you haven’t consciously made this connection, it is understood that our food choices impact how we feel.

Eating is one of the most intimate things we do. The food we eat literally becomes us: our tissue, our muscle, our bones, and ultimately our transmission. Our gastrointestinal tract controls what is passed into the body, and what is excreted; an essential interface for the immune system.

Does food make you THIS happy?

Our diet has profound effects on our gut microbiota (organisms in the intestinal tract), neuroplasticity (brain’s ability to modify structure, wiring, and function), oxidative stress (cellular damage), and systemic inflammation.

Evidence shows that food can contribute to the development, prevention, and management of mental health conditions. Although individual foods have been vilified, there is significant research that links mood disorders to a higher intake of certain foods.

-Processed meat was associated with a 13% greater risk of developing depression (1).

-Processed dairy has been linked to depression (2).

-Those who ate 67 grams of sugar per day were 23% more likely to have depression (3).

-An elevated consumption of trans fats had as much as a 48% increase in the risk of depression (4).

-Refined carbohydrates are linked to decreased mental health overall (5).

Why are these foods sabotaging mental health?—> they change the gut.

THE GUT-BRAIN-AXIS

The population of bacteria in our intestines is collectively known as the gut microbiome. These trillions of bacteria are constantly working to maintain our physiologic health, from managing our immune system to our neurotransmitters. Serotonin (the neurotransmitter we ‘hack’ with SSRI anti-depressants) is produced by our gut bacteria. In fact, up to 90% of our serotonin comes from our gut (6)! (This is why anti-depressants often have a gastrointestinal effect.)

Beyond serotonin, our microbiome is responsible for hundreds of chemicals that play a role in regulating our learning, memory, and mood. These include norepinephrine, gamma-aminobutyric acid (GABA), and tryptophan. The bacteria produce these neurotransmitters, and also respond to them, so keeping our microbiome in balance is essential to keeping our brain thriving.

The idea of ‘chemical imbalance’ as a contributor to mood conditions has largely been debunked. Instead, chronic inflammation seems to be at the root of anxiety, depression, and even PTSD. When the gut barrier is compromised or the microbiome is unhealthy, our immune system ramps up inflammation to deal with the ‘intruders’.

When systemic inflammation affects the brain, it triggers mental health issues almost like an allergic reaction. To return to anti-depressants, it’s now thought their mechanism of action may be in-part as an anti-inflammatory, lowering the overall burden (7).

Our gut and our brain are connected physically through millions of nerves. We understand what it means to “have butterflies” when we’re nervous, we have “gut feelings”, and many of us struggle with digestive changes under stress. The vagus nerve (a cranial nerve) is the major player in the complex network innervating the digestive system. Our gut contains 500 million neurons branching from the vagus nerve.

Under stress, anxiety, and other neurological dysfunction, vagal tone is dampened and signals are inhibited. In a human study, individuals with functional bowel disorders like IBS and Crohn’s disease had reduced function of the vagus nerve (8).

To make things more complicated, depression, anxiety, and stress can alter taste, perception of food, and food choices. Highly-palatable foods like sugar and fatty foods are especially pleasurable in the short term. This pushes us into a cycle of depression > poor diet > poor eating behavior that’s tough to break free from.

Hedonic Food cravings are emotional cravings for highly-palatable sugary and fatty treats.

EATING FOR HAPPINESS

As much as certain foods negatively impact our mental state, there’s also good research showing that some foods positively impact our moods! Proactively eating a healthy diet can have a protective effect against depression, anxiety, and other mood disorders. In the thick of it, it takes conscious effort to get out of the hedonic food cravings, but by actively prioritizing “good” foods you’ll make positive changes that show up as more mental clarity, more rational thought, and better emotional well-being.

1. Healthy Fats

High-quality Fats are essential to a healthy brain and mood. Omega-3 fatty acids from fish (salmon, sardines, and tuna), and nuts and seeds are the key components of our cell membranes, synaptic plasticity, and also decrease inflammation. Low levels of omega-3 fatty acids are linked to depression, suicide, and cardiovascular and inflammatory disorders (9). One study showed that increasing omega-3 fatty acid intake reduced anxiety by 20 percent (10). A diet high in DHA/EPA is linked to lower levels of depression (11).

2. Fermented Foods

Consuming fermented foods that are naturally high in probiotics helps maintain a robust population of good bacteria in the gut. A healthy microbiome = a healthy production of serotonin and decreased inflammation. Fermented foods like kimchi, sauerkraut, and kefir are functional foods that support a diverse population of bacteria.

3. Greens

Leafy green vegetables provide micronutrients like folate, magnesium, and calcium that promote neurotransmission, decrease inflammation, and support detoxification. A higher intake of green leafy vegetables can promote optimism, self-efficacy, and reduce psychological distress (12).

4. Fiber

Fiber is fodder for the gut microbiome. It provides food for ‘good’ bacteria to thrive, while also aiding in elimination of endotoxins, hormones, and waste. A high-fiber diet has been linked to decreasing a number of chronic conditions. As fibers are digested, gut microbes produce short-chain fatty acids (SCFA). An increase in SCFA affects the brain by reducing the activity related to reward from highly palatable food (13) and protecting the blood-brain-barrier (14). Prebiotic fibers from bananas, garlic, and onions can help proliferate a good bacterial population, while increasing SCFA production.

5. Eat the Rainbow

Diversity is key in a mental wellness nutrition strategy. ‘Eating the rainbow’, meaning eating a variety of colorful foods, helps you get a wide range of phytonutrients and provides different types of fiber and antioxidants. Brightly hued fruits and vegetables have brain-boosting nutrients like anthocyanin, lutein, and Vitamin C. Blueberries are a great example, as they can boost your mood in the short-term (15).

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The connection of food and mood should be something we talk about more. We are quick to look to drugs when the ‘blues’ hit, but perhaps making a more concerted effort to examine how we’re fueling ourselves can be more mainstream. After all, don’t we want to thrive? Feeling happier and more content can be a powerful motivator for dietary change. Good nutrition is as important to mental health as it is to physical health.

Of course, a nutrition strategy is just a piece in the puzzle of solving anxiety, depression, and severe mood issues. Reach out to a therapist for one-on-one support specific to your concerns.

CLICK HERE to get a FREE 7-Day Eating For Happiness Meal Plan

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Want to work with a functional nutritionist to personalize your diet? Struggling with hormone imbalance, IBS, weight gain, mood changes? Let's look at FOOD FIRST. Read more about Functional Nutrition at The Facility here.

CLICK HERE to schedule a FREE 15-Minute Nutrition Consult with Kate to determine your best course of action!

Sources:

1. Zhang Y, Yang Y, Xie MS, et al. Is meat consumption associated with depression? A meta-analysis of observational studies. BMC Psychiatry. 2017;17(1):409. Published 2017 Dec 28. doi:10.1186/s12888-017-1540-7

2. Popa TA, Ladea M. Nutrition and depression at the forefront of progress. J Med Life. 2012;5(4):414-419. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539842/

3. Knüppel, A., Shipley, M.J., Llewellyn, C.H. et al. Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the Whitehall II study. Sci Rep 7, 6287 (2017). https://doi.org/10.1038/s41598-017-05649-7

4. Sánchez-Villegas A, Toledo E, de Irala J, Ruiz-Canela M, Pla-Vidal J, Martínez-González MA. Fast-food and commercial baked goods consumption and the risk of depression. Public Health Nutr. 2012 Mar;15(3):424-32. doi: 10.1017/S1368980011001856. Epub 2011 Aug 11. PMID: 21835082.

5. Rao TS, Asha MR, Ramesh BN, Rao KS. Understanding nutrition, depression and mental illnesses. Indian J Psychiatry. 2008;50(2):77-82. doi:10.4103/0019-5545.42391

6. Fung, T.C., Vuong, H.E., Luna, C.D.G. et al. Intestinal serotonin and fluoxetine exposure modulate bacterial colonization in the gut. Nat Microbiol 4, 2064–2073 (2019). https://doi.org/10.1038/s41564-019-0540-4

7. Miller AH, Raison CL. The role of inflammation in depression: from evolutionary imperative to modern treatment target. Nat Rev Immunol. 2016;16(1):22-34. doi:10.1038/nri.2015.5

8. Pellissier S, Dantzer C, Mondillon L, Trocme C, Gauchez AS, Ducros V, Mathieu N, Toussaint B, Fournier A, Canini F, Bonaz B. Relationship between vagal tone, cortisol, TNF-alpha, epinephrine and negative affects in Crohn's disease and irritable bowel syndrome. PLoS One. 2014 Sep 10;9(9):e105328. doi: 10.1371/journal.pone.0105328. PMID: 25207649; PMCID: PMC4160179.

9. Sublette ME et al. Meta-analysis: effects of eicosapentaenoic acid in clinical trials in depression. J Clin Psychiatry. 2011;72(12):1577-1584. https://pubmed.ncbi.nlm.nih.gov/21939614/

10. Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial. Brain Behav Immun. 2011 Nov;25(8):1725-34. doi: 10.1016/j.bbi.2011.07.229. Epub 2011 Jul 19. PMID: 21784145; PMCID: PMC3191260

11. Giles GE, Mahoney CR, Kanarek RB. Omega-3 fatty acids influence mood in healthy and depressed individuals. Nutr Rev. 2013 Nov;71(11):727-41. doi: 10.1111/nure.12066. Epub 2013 Oct 22. PMID: 24447198.

12. Głąbska D, Guzek D, Groele B, Gutkowska K. Fruit and Vegetable Intake and Mental Health in Adults: A Systematic Review. Nutrients. 2020 Jan 1;12(1):115. doi: 10.3390/nu12010115. PMID: 31906271; PMCID: PMC7019743.

13. Byrne CS, Chambers ES, Alhabeeb H, Chhina N, Morrison DJ, Preston T, Tedford C, Fitzpatrick J, Irani C, Busza A, Garcia-Perez I, Fountana S, Holmes E, Goldstone AP, Frost GS. Increased colonic propionate reduces anticipatory reward responses in the human striatum to high-energy foods. Am J Clin Nutr. 2016 Jul;104(1):5-14. doi: 10.3945/ajcn.115.126706. Epub 2016 May 11. PMID: 27169834; PMCID: PMC4919527.

14. Bourassa MW, Alim I, Bultman SJ, Ratan RR. Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health? Neurosci Lett. 2016 Jun 20;625:56-63. doi: 10.1016/j.neulet.2016.02.009. Epub 2016 Feb 8. PMID: 26868600; PMCID: PMC4903954.

15. Khalid S, Barfoot KL, May G, Lamport DJ, Reynolds SA, Williams CM. Effects of Acute Blueberry Flavonoids on Mood in Children and Young Adults. Nutrients. 2017 Feb 20;9(2):158. doi: 10.3390/nu9020158. PMID: 28230732; PMCID: PMC5331589.

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