This month’s publication in JAMA Psychiatry, by researchers from the University of Toronto, Canada, shows small to moderate improvements in depressive symptoms when people are on a ketogenic diet (randomized clinical trials with a total of 50 studies and 41,718 participants). [1]
What is a ketogenic diet?
A ketogenic diet (keto diet) is a diet high in fat, moderate in protein, and low in carbohydrates. The standard keto diet consists of 70 to 80 percent fats, 10 to 20 percent proteins, and 5 to 10 percent carbohydrates. So, on a keto diet, people eat very little sugar and eat mostly meat, fish, eggs, nuts, seeds, cheese, and oils such as olive oil.
Three ways the ketogenic diet can influence mental health
- Ketogenic diet acts on neurotransmitters implicated in depression: It increases the brain’s production of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, while reducing glutamate, an excitatory neurotransmitter. This is thought to stabilize neural networks and decrease hyperexcitability, mechanisms implicated in depression. [1]
- Ketogenic diet improves mitochondrial function by increasing ATP production via fatty acid oxidation and ketone bodies, particularly β-hydroxybutyrate (βHB). βHB serves as an efficient substrate for mitochondrial respiration and supports energy demands during stress or hyperexcitation. [2]
- Ketogenic diet decreases inflammation primarily through the actions of βHB, which reduces inflammasome-mediated inflammation. [3]
The vicious cycle
It is interesting to note that there is a bidirectional relationship between what we eat and depression. While poor dietary habits can worsen depression symptoms, depression itself can lead to unhealthy eating habits, leading to a vicious cycle. The key is to stop this cycle.
The emerging field of psychonutrition and the benefits of the Mediterranean diet
The emerging field of psychonutrition highlights the importance of diet in psychiatric care. [4]
Despite the ketogenic diet being in the spotlight recently, the most evidence-based diet for reducing depressive symptoms and incidence is the Mediterranean diet, rich in fruits, vegetables, whole grains, fish, nuts, seeds, plain yogurts, and healthy fats such as olive oil and avocados, and limited in processed foods and sugar-sweetened beverages.
This Mediterranean diet provides key nutrients like omega-3 fatty acids (which support brain health and reduce inflammation) [5], antioxidants from fruits and vegetables [6], and probiotics (there is an association between gut-health-promoting diet and depression). [7]
But what is also important is to supplement the diets of depressed people with the micronutrients they might be lacking.
Micronutrient deficiencies that are commonly observed in depressed people
- B vitamins: Vitamin B6, folate, and vitamin B12 deficiency are frequently linked to depression due to their roles in neurotransmitter synthesis and neurological function. [8]
- Vitamin D: Vitamin D deficiency is also prevalent, particularly in cases of seasonal affective disorder, and is associated with increased risk and severity of depressive symptoms. [9]
- Magnesium, zinc, and selenium serum levels are often too low, and their deficiency has been well documented in some depressed patients. [10]
- Low iron, copper, and iodine levels have also been implicated in depressed patients. [11]
It is important to measure those serum micronutrients and to supplement them if there is a deficiency.
Conclusion
The new field of psychonutrition teaches us how important our diet is for our mental health.
Recent studies show the benefits of a ketogenic diet, while older studies emphasize the benefits of the Mediterranean diet. What both diets have in common is that they recommend we stay away from sugar and ultra-processed foods.
So, to stay healthy and emotionally balanced, let’s say no to cakes, cookies, and sugary drinks.