The brain belongs to the body most energy-intensive organ. Although it represents only 2% of the body’s mass, it consumes approximately 20% of its energy. Typically, the brain is fueled primarily by glucose produced by the breakdown of carbohydrates. But when there isn’t enough glucose to go around, the brain begins to consume fat-derived compounds called ketone bodies for fuel.
This change, ketosis, occurs when you follow a ketogenic diet, or keto diet, a high-fat, low-carb diet. Scientists have been studying how ketosis changes the brain since the early 1920s, when the diet was introduced as a treatment for treatment-resistant epilepsy in children. Some studies have also suggested that it may help treat symptoms of Alzheimer’s disease.
And now, results from several small trials strengthen the argument that the keto diet can help treat mental health conditions such as depression, bipolar disorder, schizophrenia And anorexia nervosa. The results are preliminary: randomized controlled trials are underway to better assess who could be helped by the diet and to what extent it could benefit them. But together, the findings support a theory that some mental illnesses are considered metabolic disorders, in which the brain’s ability to get energy from its preferred sources is compromised.
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This understanding of the keto diet “really forced me to rethink the way I understand mental illness,” says Chris Palmer, a psychiatrist who studies metabolism at Harvard Medical School.
The energy connection
The idea that mental illness and metabolism are linked makes sense, regardless of the potential effects of the keto diet. “Metabolism is essentially the backbone of physiology,” says Isaac Marin-Valencia, a neurologist studying metabolic diseases at the Icahn School of Medicine at Mount Sinai. “Without metabolism, life would not be possible. It is therefore not surprising that virtually all human diseases [has] a metabolic component.
Scientists already knew that people with psychiatric disorders such as depression, bipolar disorder And schizophrenia are at higher risk of metabolic diseases such as diabetes, obesity, and polyendocrine ovarian metabolic syndrome, or PMS (formerly polycystic ovary syndrome, or PCOS). The opposite is also true: people with metabolic disorders are also more likely to suffer from psychiatric illnesses. Serious mentaldiseases also often involve disturbances in glucose metabolism in the brain. In bipolar disorderFor example, people whose brains failed to convert glucose into energy had symptoms earlier and more frequently.
This may explain why the ketogenic diet, which bypasses glucose by providing an alternative fuel source, shows promise in treating these diagnoses. In a randomized controlled trial with 88 participants published in Februarypeople with treatment-resistant depression who followed a strict keto diet saw a slight improvement in their symptoms compared to a control group. Other smaller pilot trials found keto improved bipolar disorder And symptoms of schizophrenia; It is important to note that study participants continued to take their medications to treat these conditions. At least five randomized controlled trials are currently underway to more rigorously test the diet’s effects.
“These research results are early; they’re preliminary. But it definitely gives us a signal that we should do more research,” says Shebani Sethi, a metabolic psychiatrist at Stanford University.
A big unanswered question is how the keto diet achieves this. This effect is likely due to multiple factors beyond simply providing the brain with an alternative fuel source, Palmer says. Ketosis can affect the balance of two of the brain’s essential neurotransmitters, glutamate and gamma-aminobutyric acid (GABA), which excite and inhibit neuronal firing, respectively. This regulatory effect helps explain how the keto diet can treat epilepsy, and could also explain why the diet might be helpful in other conditions as well. Ketosis also supports overall mitochondrial function, the powers of a cellwhich create the molecules that brain cells use for energy. The diet also appears to reduce inflammation throughout the body, a factor also linked to many mental illnesses; it is possible that reduce inflammation can indirectly improve the symptoms of these disorders.
A potential treatment for anorexia nervosa
The keto diet may also have benefits for other types of mental illnesses. A small study published this month found that the diet improvement in eating disorder symptoms in people suffering from anorexia nervosa who were either slightly underweight or who had managed to return to a healthy weight.
The idea that a highly restrictive diet could help treat a highly restrictive eating disorder such as anorexia nervosa seems counterintuitive. “It’s a bit paradoxical,” says the study’s lead author, Guido Frank, of the University of California, San Diego. But even though the keto diet limits the food groups people can eat, it doesn’t necessarily limit the calories they eat. Trial participants did not experience clinically significant weight loss while on the diet.
Study co-author Caroline Beckwith, a wellness coach who acted as an advisor to study participants, herself recovered from anorexia nervosa after being treated with the keto diet. Before following the diet, “I was so afraid of eating fat. It was a whole group of foods that I didn’t eat,” she says. But when she didn’t gain weight on keto, she felt encouraged to continue. Within weeks, she says, she experienced the first day in many years where she wasn’t concerned about dietary restrictions and exercise. “I realized, ultimately, that it was hours and hours without any anorexic thoughts,” Beckwith adds.
Palmer and Sethi emphasize that anyone interested in trying a ketogenic diet to treat mental illness should talk to their doctor first. Diet can interact unpredictably with psychiatric medications. He can also trigger episodes of maniaincluding in people without a psychiatric history, which can be destabilizing. “Please don’t try to do it yourself,” Palmer says.
It’s tempting that a single intervention can help treat illnesses as varied as anorexia nervosa, depression and Alzheimer’s disease. And there are several reasons why a common treatment might prove useful for these seemingly disparate conditions. Alzheimer’s disease and depression often occur together, suggesting that some of the same biological mechanisms may underlie both; other pairs of these conditions have similar relationships. In addition, certain conditions may be more similar to the current count of diagnostic categories because bipolar disorder and schizophrenia, for example, can be part of the same spectrum of conditions.
More broadly, metabolism is increasingly linked to a wide range of health conditions, suggesting that metabolic treatments, whether diets, medications, or exercise programs, can affect many systems in the body. Glucagonlike peptide 1 (GLP-1) drugs, for example, primarily target metabolism and weight, but they also affect the brain. help reduce the risk of substance use and certain eating disorders.
“Metabolism affects every cell, tissue and organ in your body,” says Palmer. Therapy that addresses metabolic dysfunction, he adds, “can be a powerful treatment.”
