What Is The Link Between Diet And Mental Illness?

Introduction

The food we eat certainly plays a major role in our physical health and overall wellbeing. But did you know that it can also affect our mental state and mood?

The interaction between food and mental wellbeing can be as simple as quick relief from hunger leading to a better mood. Or as complex as the gut bacteria affecting the chemicals that our brain produces which has a deeper effect on our psychological state¹. Thus, this relationship is actually an intricate one which cannot be summarised easily. However, with this blog, we will try to explain you the broader connection between diet and mental health that will empower you to make the right food choices for your brain.

The Link Between Diet and Mental Illness

Let us find out the many ways in which diet and mental health are closely intertwined. Keep in mind that this relationship is not easy to study or make unquestionable claims about. But scientists have been studying this link for some time now, so we have some general ideas.

The Gut-Brain Connection

You may know that our food is not only digested by the enzymes our stomach secretes but it is also aided very much by the healthy bacteria in our stomachs. These bacteria are essential for normal digestion. The first way these little organisms help our mood is by allowing us to have smooth digestion. Without good bacteria we may experience indigestion or other digestive issues. These can cause us anxiety and stress issues¹.

The microorganisms across our body are collectively known as the microbiome, and each person’s microbiome is unique to them¹. The gut bacteria play and important role in the production of neuro-chemicals like serotonin, dopamine, GABA, norepinephrine, and others². While serotonin is mainly involved with mood regulation, other neurotransmitters are essential for mental functions like focus, feeling motivated, feelings of reward and anxiety³. What your eat influences your gut microbiota and thus the secretion of these neurotransmitters, which can affect your mental and emotional state.

Foods rich in in omega-3 fats such as fish, fermented foods and probiotics, high fibre foods like whole fruits and vegetables, and tryptophan-rich foods (amino-acid which is converted to serotonin) like eggs, tofu and cheese are all good for the gut microbiome, which in turn helps stabilize our mental state⁴.

On the other hand, excessive, irrational use of antibiotics or medications that destroy this microbiome by killing off the bacteria in our gut can also lead to poor mental health⁵. It has been noted that people with irritable bowel syndrome (consequently their microbiome is out of balance) are likely to also have disorders such a depression⁴. 

According to a recent study¹⁴ conducted on people above the age of 50, higher anxiety levels were believed to be linked to diets rich in saturated fat and sweets. In my opinion, one should restrict sugar intake and indulge in some physical activity to keep mental illness at bay.

Dr. Siddharth Gupta, B.A.M.S, M.D (Ayu)

The Role of Inflammation

• The foods you eat play a key role in your brain’s health and mood too. Diets which are high in processed or refined foods are found to be harmful for brain. These can cause inflammation and oxidative stress to the brain cells.
• Refined foods impair the ability of brain tissue to fight free radicles, thereby inflicting chronic damage that might affect brain function and worsen the mood, causing disorders such as depression.  Hence, following a processed food diet and avoiding the necessary good nutrition might cause inflammation that can harm your brain and mental health⁶. 
• Pro-inflammatory foods such as red and processed meats, organ meats, sugary drinks like soda, and refined grains like white bread, pasta, and white rice should therefore be consumed cautiously.
• On the other hand, anti-inflammatory foods like leafy green vegetables, carrots, pumpkins, and sweet potatoes (yellow vegetables), fruit juice, and oily fishes like salmon and sardine etc. are good for the brain⁷.
• Some studies suggest that the Mediterranean diet rich in vegetables, seafood, whole grains and fruits may help reducing depression symptoms⁸. 

Moreover, eating regular balanced meals contributes by supporting blood sugar levels. Low blood sugar levels can cause irritability, fatigue and mood swings.

The Basic Factors to Understand in Diet and Mental Illness

Some foods such as coffee and chocolate are well-known mood stimulants.  Caffeine in coffee is a stimulant for the central nervous system, it can help feel charged up and ready for work. Studies also show that people who consume caffeine (mainly through coffee) have a lower risk of mental issues like Alzheimer’s, and dementia^9,10. Dark chocolate is found to have an anti-inflammatory effect and it helps stimulate serotonin production thus elevating the mood¹¹. Although there is no singular food or dish that can conclusively ‘cure’ any mental sickness, your diet still affects how you feel.

The following general tips will guide you towards the right diet and dietary habits that can help improve your mental wellbeing.

• Sharing brings happiness: One aspect of food is that we typically sit down and share our meals with loved ones. This social activity is a routine that provides us with social and psychological benefits¹². 
• Disciplined routine: A healthy diet does not only mean nutritious food, people with an unhealthy relationship with food also need to manage their portion size and mealtimes. Eating at irregular times might cause obesity, diabetes, and cardiovascular diseases¹³. There are many eating disorders. In this way, there is a negative impact on physical and mental health due to poor nutrition.
• Nutrition for good health: Nutritious, healthy food is the surest way to support good physical health. With a healthy diet which include whole grains, vegetables, fish etc, you are also supporting your immune system, brain health and heart health⁸.
• Must include: Pre and probiotics, curd, fresh fruits and vegetables, whole grains, which helps to improve gut microbiota^1,8.
• Must avoid: Deep-fried, processed food, food and beverages with high sugar content, alcoholic beverages. 

A healthy dietary pattern, defined by high intakes of fruit, vegetables, whole grains, olive oil, fish, low-fat dairy, and antioxidants, as well as low intakes of animal foods, are linked to a lower incidence of depression, according to a recent study. In contrast, a Western-style diet with a high intake of red and processed meats, refined grains, sweets, high-fat dairy products, butter, and potatoes and a low intake of fruits and vegetables has related to a higher risk of depression¹⁵.

Dr. Rajeev Singh, BAMS

Conclusion

It may not be the easiest to visibly see the effects of healthy diets on mental illness. That is because both the brain and microbiome are complex systems. But we know that a poor diet is linked to poor mental and physical health, as well as a weaker immune system. Studies have enough evidence to confirm the benefits of good nutrition on mental health and mood. Not to mention, diets that are not balanced, may lead to long-term health issues like diabetes. If you need help, then speak to our doctor; they can advise you on diet and mental illness, what foods you should include and things you should avoid.

References

1. Ochoa-Repáraz J, Kasper LH. The Second Brain: Is the Gut Microbiota a Link Between Obesity and Central Nervous System Disorders? Current Obesity Reports. 2016 Feb 11;5(1):51–64. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4798912/3

2. Dicks LMT. Gut Bacteria and Neurotransmitters. Microorganisms. 2022 Sep 14;10(9):1838. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9504309/

3. Martin EI, Ressler KJ, Binder E, Nemeroff CB. The Neurobiology of Anxiety Disorders: Brain Imaging, Genetics, and Psychoneuroendocrinology. Psychiatric Clinics of North America [Internet]. 2009 Sep;32(3):549–75. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC3684250/

4. Zhang P. Influence of Foods and Nutrition on the Gut Microbiome and Implications for Intestinal Health. Int J Mol Sci. 2022;23(17):9588. https://pmc.ncbi.nlm.nih.gov/articles/PMC9455721/

5. Dinan K, Dinan T. Antibiotics, and mental health: The good, the bad and the ugly. Journal of Internal Medicine. 2022 Jul 12;292(6). Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC9796968/

6. Selhub E. Nutritional psychiatry: Your Brain on Food [Internet]. Harvard Health Blog. Harvard Health Publishing; 2022. Available from: https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626

7. Belliveau R, Horton S, Hereford C, Ridpath L, Foster R, Boothe E. Pro-inflammatory diet and depressive symptoms in the healthcare setting. BMC Psychiatry. 2022 Feb 17;22(1). Available from: https://link.springer.com/article/10.1186/s12888-022-03771-z

8. Skarupski KA, Tangney CC, Li H, Evans DA, Morris MC. Mediterranean diet and depressive symptoms among older adults over time. The journal of nutrition, health & aging [Internet]. 2013 Feb 19 [cited 2019 Jun 19];17(5):441–5. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4454450/

9. Nehlig A. Effects of coffee/caffeine on Brain Health and disease: What Should I Tell My patients? Practical Neurology [Internet]. 2015 Dec 16;16(2):89–95. Available from: https://pn.bmj.com/content/16/2/89

10. Chen JQA, Scheltens P, Groot C, Ossenkoppele R. Associations Between Caffeine Consumption, Cognitive Decline, and Dementia: A Systematic Review. Journal of Alzheimer’s Disease. 2020 Nov 4;78(4):1–28. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC7836063/

11. Samanta S, Sarkar T, Chakraborty R, Rebezov M, Shariati MA, Thiruvengadam M, et al. Dark chocolate: An overview of its biological activity, processing, and fortification approaches. Current Research in Food Science [Internet]. 2022;5:1916–43. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9589144/

12. Dunbar RIM. Breaking Bread: The Functions of Social Eating. Adaptive Human Behavior and Physiology [Internet]. 2017;3(3):198–211. Available from: https://link.springer.com/article/10.1007/s40750-017-0061-4

13. Manoogian ENC, Chaix A, Panda S. When to Eat: The Importance of Eating Patterns in Health and Disease. Journal of Biological Rhythms [Internet]. 2019 Dec;34(6):579–81. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7213043/ 

14. Masana MF, Tyrovolas S, Kolia N, Chrysohoou C, Skoumas J, Haro JM, Tousoulis D, Papageorgiou C, Pitsavos C, Panagiotakos DB. Dietary Patterns and Their Association with Anxiety Symptoms among Older Adults: The ATTICA Study. Nutrients. 2019 May 31;11(6):1250. doi: 10.3390/nu11061250. PMID: 31159322; PMCID: PMC6627391. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6627391/

15. Li Y, Lv MR, Wei YJ, Sun L, Zhang JX, Zhang HG, Li B. Dietary patterns and depression risk: A meta-analysis. Psychiatry Res. 2017 Jul;253:373-382. doi: 10.1016/j.psychres.2017.04.020. Epub 2017 Apr 11. PMID: 28431261. Available from: https://pubmed.ncbi.nlm.nih.gov/28431261/

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