Food & Mood

Many people will notice changes in appetite and food cravings when experiencing low mood, anxiety or chronic stress. However, the reverse association is less well recognized. That is, the types of food consumed can directly influence mood.¹ The gut and the brain are powerfully interconnected and any disruption in one of these organs will often impact the other.

Awareness of how these 3 diet-related pathways in which food may influence mood can help individuals make better choices:

Swings in blood sugar levels

Frequent intake of refined carbohydrate and sugary foods cause our blood sugars to rapidly rise and then crash back down. These dips in low blood sugars create feelings of irritability, anxiety and poor decision control.² Diets rich in refined carbohydrates have also been linked to depression.³

Inflammation

Most healthful foods, such as oily fish, vegetables, fruits and nuts, contain nutrients that have anti-inflammatory effects in the body.⁴ On the other hand, foods that are heavily processed or rich in sugar, refined carbohydrates and saturated fat have pro-inflammatory effects.⁴ Inflammation is strongly linked to depression and mood disorders. Emerging studies indicate that poor diets rich in pro-inflammatory foods are associated with higher depression scores in various populations.⁵

Changes in the gut microbiome

Strong evidence now suggests that the gut microbiome (e., all the microorganisms that live in our gut) interacts with the brain in bi-directional processes that can influence mental and physical health. For example, impressive research shows that animals display depressive-like behavior when they receive a fecal transplant from humans with depression.⁶ Diet is a key factor that can influence the composition of our gut microbiome and integrity of the digestive tract, and thereby potentially promote positive or negative mood states. In general, a dietary pattern that is high in fiber and unsaturated fats and low in sugar, saturated fats and artificial sweeteners is associated with a healthier gut microbiome.⁷

There are several common dietary factors in each of the above that are likely to influence mood. The Mediterranean diet is characterized by high intake of fiber from vegetables, fruit, whole grains and unsaturated fats from olive oil, fish and nuts. Meanwhile, it has a low intake of sugar and processed foods that are typically high in refined carbohydrate and/or saturated fat. Indeed, studies have shown that populations following a Mediterranean diet have low rates of depression and anxiety.^5,8 This is a good dietary pattern to follow to optimize mental health, as well as the many other physical health benefits it provides.

However, mental health may be positively influenced by non-food related external factors and circumstances, which can cause cravings for unhealthy foods as a coping mechanism. Engaging in non-food related activities, such as exercise, deep breathing or self-care rituals, can help de-stress and calm our over-active minds while distracting from food cravings. Establishing positive lifestyle habits in this way will help our mental health and reduce reliance on “comfort eating”.

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References

1. Firth J, Gangwisch JE, Borisini A, Wootton RE, Mayer EA. Food and mood: how do diet and nutrition affect mental wellbeing? BMJ. 2020;369:m2382.
2. Aucoin M, Bhardwaj S. Generalized Anxiety Disorder and Hypoglycemia Symptoms Improved with Diet Modification. Case Rep Psychiatry. 2016;2016:7165425.
3. Gangwisch JE, Hale L, Garcia L, Malaspina D, Opler MG, Payne ME, Rossom RC, Lane D. High glycemic index diet as a risk factor for depression: analyses from the Women’s Health Initiative. Am J Clin Nutr. 2015 Aug;102(2):454-63.
4. Shivappa N, Steck SE, Hurley TG, Hussey JR, Hébert JR. Designing and developing a literature-derived, population-based dietary inflammatory index. Public Health Nutr. 2014 Aug;17(8):1689-96.
5. Lassale, C., Batty, G.D., Baghdadli, A. et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Mol Psychiatry. 2019; 24, 965–986.
6. Kelly JR, Borre Y, O’ Brien C, Patterson E, El Aidy S, Deane J, Kennedy PJ, Beers S, Scott K, Moloney G, Hoban AE, Scott L, Fitzgerald P, Ross P, Stanton C, Clarke G, Cryan JF, Dinan TG. Transferring the blues: Depression-associated gut microbiota induces neurobehavioural changes in the rat. J Psychiatr Res. 2016 Nov;82:109-18.
7. Sonnenburg ED, Sonnenburg JL. The ancestral and industrialized gut microbiota and implications for human health. Nat Rev Microbiol. 2019 Jun;17(6):383-390.
8. Ljungberg T, Bondza E, Lethin C. Evidence of the Importance of Dietary Habits Regarding Depressive Symptoms and Depression. Int J Environ Res Public Health. 2020;17(5):1616.