Reprinted with permission from Brain Energy by Christopher M. Palmer, MD (BenBella Books, Inc., 2022)
what do we eat when we eat, and the amount of food we eat has direct effects on metabolism and mitochondria. Everyone knows that diet plays a role in obesity, diabetes, and cardiovascular disease. What most people may not know is that diet also has profound effects on mental health and the brain.
This field is huge. Countless tens of thousands of research articles and textbooks have explored the effects of diet on metabolism and mitochondria. Most of this research has focused on obesity, diabetes, cardiovascular disease, Alzheimer’s disease, aging, and longevity. However, these researchers don’t usually see a connection to mental health.
Links go beyond interrelationships. They overlap at the level of neural circuits in the brain, and of course the entire metabolic and mitochondrial network within the human body. For example, neural circuits that drive appetite and eating behaviors are also directly implicated in addiction to tobacco, alcohol, and heroin. This is not very surprising to most people. What may be even more surprising is that the neural circuits of loneliness directly overlap with the neural circuits that warn of hunger. This study has been published in natureshowed that chronic social isolation in Drosophila led to increased eating And the Lack of sleep. A “social” problem resulted in changes in appetite and sleep. When the researchers artificially stimulated the social isolation neural circuit, it caused the flies to eat more and sleep less. Another study identified specific GABA and serotonin neuronal circuits that were directly involved in obesity And the Anxiety and depression. One neural circuit plays a role in how much you weigh And the How do you feel.
Some people call this field food psychiatry, One looking at the role of diet in mental health. Personally, I feel this is too narrow. It’s more than the effect of diet on brain function. It also relates to how our mental state affects our metabolism, which can affect appetite and feeding behaviour, which can affect overall health. It is a two way relationship. Metabolism affects mental and mental influence on metabolism.
There are at least seven different ways that nutritional interventions can help with mental symptoms:
- Addressing nutritional deficiencies, such as folic acid, vitamin B12, and thiamine deficiency.
- Removing food allergens or toxins. For example, some people have an autoimmune disorder called celiac disease that results in inflammation and other metabolic problems in response to gluten. This can also affect brain function. I have described the toxic effects of TFAs. There are many other food ingredients that can impair mitochondrial function.
- Eating a “healthy diet,” such as the Mediterranean diet, may play a role for some people.
- Improve the gut microbiome.
- Improving metabolism and mitochondrial function through nutritional intervention. This includes changes in insulin resistance, metabolic rate, number of mitochondria in cells, general health of mitochondria, hormones, inflammation, and many other known metabolic regulators.
- Losing weight can help alleviate problems associated with obesity.
- Weight gain can be a life-saving intervention for those who are severely underweight.
There is also evidence that fasting, intermittent fasting (IF), and fasting-mimicking regimens may play a role in the treatment of psychiatric disorders. They all lead to the production of ketone bodies, which are made when fat is used as an energy source. Fats are converted into ketones. Interestingly, this process occurs exclusively in mitochondria, which is another role of these remarkable organelles.
We have evidence that IF improves mood and cognition and protects neurons from damage in animal models of epilepsy and Alzheimer’s disease. A group of researchers set out to understand the how and why. You’d never guess what they found – it’s mitochondria! The researchers put the mice on an IF routine. They found that the hippocampus, a brain region often involved in depression, anxiety and memory disorders, was largely driving improvements from IF. It appears to be primarily due to the higher levels of GABA activity, which reduced hyperexcitability. Next, the researchers went further to understand the reason for this change in GABA activity. They removed Sirtuin 3 from mice in two different ways. This protein is exclusive and essential to the health of mitochondria. When they did, all the benefits were lost. This clearly points the mitochondria directly into the benefits of IF on brain health.