How Can Nutrition Help Depression

What is a Healthy Diet?

A diet consists of the foods a person habitually eats. A healthy diet such as a Mediterranean diet decreases risk of depression. A Mediterranean diet consists of:

• high intake of fruits, vegetables, nuts, and legumes
• moderate intake of poultry, eggs, and dairy products
• occasional intake of red meat.

What is an Unhealthy Diet?

An unhealthy diet increases risk of diseases such as obesity and diabetes. Additionally, increased risk of depression is associated with unhealthy eating which consists of high intake of red or processed meats, refined grains, sweets, high-fat dairy products, butter, and potatoes. Unhealthy eating also includes low intake of fruits and vegetables.

 

Glycemic Index and its Effects on your Body and Mood

All foods have a glycemic index or sugar level. Glycemic index is a measure of the amount of sugar in food and is a relative ranking of how quickly each food digests. Less healthy foods tend to have more sugar (higher glycemic indexes) and may be detrimental to psychological well-being. In one study of increased sugary foods in the diet of healthy volunteers increased depressive symptoms. Sugary food spikes sugar levels in the blood. This sugar spike causes insulin release in the body. This insulin spike aids in digestion; however, the insulin level quickly drops after food is digested leading to release of other regulatory hormones such as cortisol. These regulatory hormones counteract insulin and may impact anxiety, irritability, and hunger. Recurrent low blood sugar is associated with mood disorders. To digest foods with less sugar (lower glycemic index), the body releases insulin more slowly leading to the blood sugar level remaining more constant throughout the day and decreasing risk of depression.

Why is Inflammation Important?

Diets consisting of high sugar foods also increase inflammation in the body. People who follow a Mediterranean diet may exhibit less inflammatory markers. High caloric intake and high intake of unhealthy, saturated fats may be harmful to brain health and lead to cognitive decline,  memory (hippocampal) dysfunction, and damage to the brain. In one study, people with depression scored higher in “dietary inflammation.”  These people had higher intake of trans fats and refined carbohydrates (e.g. Doritos) and lower intake of anti-inflammatory foods such as omega-3 fats (e.g. fish). The link between inflammation, diet, and mental health requires more study.

 

Gut Health Impacts Brain Health

Another way in which diet may influence the brain is through a person’s gut microbiome. The human gut is home to numerous microbial organisms including bacteria, viruses, and archaea. The gut microbiome interacts with the brain through neural, hormonal, and inflammatory signaling pathways. The possible link between the gut microbiome and mental health is based on the follow observations: scientists found major depressive disorder in humans with gut alterations, emotion-like behavior in rodents changes when these rodents experience changes in their gut microbiomes, and transfer of gut microbiota from depressed humans to rodents induces possible depressive behaviors. Poor diet and low grade systemic immune activation may lead to compromise of a mucus layer of or absorption in the gut. This compromise may be leaky gut syndrome, which is related to a diet low in fiber and high in saturated fats, refined sugars, and artificial sweeteners. Conversely, consuming a Mediterranean diet may promote microbes into producing anti-inflammatory metabolites. Furthermore, one study found that healthy individuals who ingest probiotics (which theoretically target the gut) can change the brain’s response to tasks that require emotional attention and may reduce symptoms of depression.

 

In Conclusion

Diet alone may not help every person with depression but could be a tool along with other healthy lifestyle choices, therapy, and medication that can control depression.

 

 

Works Cited:

Firth, J., Gangwisch, J. E., Borsini, A., Wootton, R. E., & Mayer, E. A. (2020, June 29). Food and mood: how do diet and nutrition affect mental wellbeing? doi:10.1136/bmj.m2440

Tello, M. (2020, January 29). Diet and Depression. Retrieved from Harvard Health Publishing: Harvard Medical School: https://www.health.harvard.edu/blog/diet-and-depression-2018022213309