Have you ever had a gut feeling before? Maybe you’ve had butterflies in your stomach when taking a risk, or felt something in the pit of your stomach when receiving bad news. Are these just idioms, or is there something else there? On my journey to become a registered dietitian, the connection between food and physical health is a common theme. Something we talk about much less is the connection between food and mental health. While Inflammatory Bowel Disease (IBD) is often thought of as a physical disease, the mental impact cannot be ignored. In my opinion, we don’t talk enough about the IBD and mental health connection, and we certainly don’t talk enough about how food can play a role in this aspect of our disease.
Mental Health and Gut Health
What does gut health have to do with mental health? Strap on your helmet, it's time for a crash course in the connection between gut health and the brain. The gut has over 500 million nerves, which serve as a two way communication system with the brain. If your gut isn’t happy, you better believe it is going to let its good friend the brain know about it. Our guts are also responsible for producing neurotransmitters, which help to regulate physical and mental functions of the body. One important neurotransmitter that regulates mood, serotonin, is produced 95% in the intestines! Another one, GABA, can be produced by the friendly bacteria in the gut, and can help reduce feelings of anxiety, depression, and fear.
Mental Health and IBD
As you can see, the gut and the brain are basically best buds. But what does that mean for people whose guts are broken more frequently than the McDonalds ice cream machine? Unfortunately, IBD patients are at an increased risk for developing anxiety and depression, and frankly, can you blame us? We are forced to bear the burden of a lifelong chronic disease, often being diagnosed during some of the most mentally vulnerable stages of our lives. High school is hard enough without explaining why you spend half of every class in the bathroom. It might seem like the connection between intestinal health and brain health is bad news, but there is a silver lining. If we can change the health of our gut, we can change the health of our brain.
Diet and Mental Health in Healthy Individuals
In healthy individuals, certain diets have been shown to increase feelings of wellbeing, reduce feelings of depression, and improve psychological health. Both individual foods such as fruits and vegetables, as well as dietary patterns such as the mediterranean diet, have been linked to these benefits. Some foods are also associated with worse mental health. Sugar has been linked with mood disorders and depression. Excess sugar consumption is also associated with dysbiosis, a shift in the composition of the gut bacteria from helpful to harmful species.
Diet and Mental Health in IBD
In a study presented at Digestive Disease Week 2020, researchers categorized IBD patients into two groups, a high sugar group (>100 grams per day) and a low sugar group (<100 grams per day). They found that those in the high sugar group had increased feelings of fatigue, trouble with social engagement, feelings of depression, and trouble relaxing compared to IBD patients in the low sugar group.
It is important to note that sugar containing whole foods such as fruit have been strongly linked to positive health outcomes, and should be considered differently than sugars from processed foods. Added sugars from processed foods such as soda or candy are associated with an unhealthy gut, and worse overall health.
I think this is such an important study, not only because it has practical implications for IBD patients, but also because it opens doors for patients to take control of their own mental health. I don’t think I've ever had a conversation with any GI doctor about mental health, despite the increased risk we carry with IBD. Until that changes, it is reassuring to know that we have the option to eat in a way that is associated with good gut health, and therefore good mental health.
References
Choi K, Chun J, Han K, et al. Risk of Anxiety and Depression in Patients with Inflammatory Bowel Disease: A Nationwide, Population-Based Study. J Clin Med. 2019;8(5):654. Published 2019 May 10. doi:10.3390/jcm8050654
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
Stranges S, Samaraweera PC, Taggart F, Kandala NB, Stewart-Brown S. Major health-related behaviours and mental well-being in the general population: the Health Survey for England. BMJ Open. 2014;4(9):e005878. Published 2014 Sep 19. doi:10.1136/bmjopen-2014-005878
Parletta N, Zarnowiecki D, Cho J, et al. A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED). Nutr Neurosci. 2019;22(7):474-487. doi:10.1080/1028415X.2017.1411320
Brown K, DeCoffe D, Molcan E, Gibson DL. Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease [published correction appears in Nutrients. 2012 Oct;4(11)1552-3]. Nutrients. 2012;4(8):1095-1119. doi:10.3390/nu4081095