Ketogenic Diets for Psychiatric Disorders: A New Review
Where the science stands, and what it means for you.
Posted June 30, 2017 | Reviewed by Lybi Ma
Ketogenic Diets Yesterday, Today and Tomorrow
If you have a brain, you need to know about ketogenic diets. The fact that these specially-formulated low-carbohydrate diets have the power to stop seizures in their tracks is concrete evidence that food has a tremendous impact on brain chemistry and should inspire curiosity about how they work. I first became interested in ketogenic diets as a potential treatment for bipolar mood disorders, given the many similarities between epilepsy and bipolar disorder .
Ketogenic diets have been around for about 100 years, and have proved to be invaluable tools in the treatment of stubborn neurological conditions, most notably epilepsy. They have also shown promise in the management of other brain-based disorders such as Parkinson’s Disease, ALS, Traumatic Brain Injury , Multiple Sclerosis, and chronic headaches, as well as in metabolic disorders like obesity, cancer, and type 2 diabetes.
But where does the science currently stand on the ketogenic diet and psychiatric disorders like bipolar disorder , schizophrenia, and Alzheimer’s Disease? How many human studies do we have, and what do they tell us? If you are struggling with mood, attention, or memory problems, should you try a ketogenic diet? If you are a clinician, should you recommend a ketogenic diet to your patients?
A recent review article “ The Current Status of the Ketogenic Diet in Psychiatry ” by researchers at the University of Tasmania in Australia [Bostock et al 2017 Front Psychiatry 20(8)] brings us nicely up to date on all things ketogenic and mental health. I summarize the paper below and offer some thoughts and suggestions of my own. [Full disclosure: I am a psychiatrist who studies nutrition and eats a ketogenic diet.]
First, some basics for those of you who are unfamiliar with these special diets.
What are Ketogenic Diets?
Definitions vary, but what all ketogenic diets have in common is that they are very low in carbohydrate (typically 20 grams per day or less) and relatively high in fat. The goal is to lower blood sugar and insulin levels; when these are nice and low, the body naturally turns to fat (instead of sugar) as its primary source of energy. Most ketogenic diets also limit protein (to no more than the body requires), because excess protein can raise blood sugar and insulin levels to some extent. Body fat and fat from the diet then break down into ketones, which travel through the bloodstream and can be burned by various cells throughout the body, including most brain cells. Ketone levels rise in the blood, urine and breath within days, and can be measured using various home test methods, but it can take weeks for the body to become efficient at burning fat for energy, and for full benefits to be realized.
When a person is “in ketosis”, fasting morning blood glucose levels tend to average between 60 and 85 (mg/dl), and blood ketone levels rise to at least 0.5 mM (with much higher levels recommended for certain conditions). These parameters distinguish ketogenic diets from other low-carbohydrate diets, which may contain too much protein and/or carbohydrate to produce these metabolic effects.
How do Ketogenic Diets Work?
It remains unclear how ketogenic diets work to control seizures, let alone how they may improve psychiatric symptoms. On a fundamental level, we are not even sure whether it is the presence of ketones, the reduction in blood sugar, the reduction in insulin and other growth-promoting hormones , or the combination of all of these which are responsible for the brain-stabilizing effects of these diets. Theories abound, and include altered neurotransmitter levels, changes in electrolyte gradients (lower intracellular sodium and calcium), reduction in markers of inflammation, and improved mitochondrial function. The general consensus is that the brain functions more cleanly and efficiently when a significant portion of its energy comes from ketones, calming overactive and overly-reactive brain cells.
What about Ketone Supplements?
You can raise your blood ketone levels without changing your diet, by either taking expensive ketone supplements or by ingesting fats high in medium chain triglycerides (MCTs), which the liver rapidly transforms into ketones. Purified MCTs are available for purchase, or you can simply take coconut oil, which is naturally rich in MCTs. You’ll see below that these approaches can be effective short-term, but my opinion is that they simply mask the underlying disease, which continues to worsen due to ongoing high insulin and/or blood glucose levels.
SUMMARY OF THE SCIENCE
I’ve listed all relevant studies covered in the 2017 Bostock review below, paying special attention to the human studies, and supplementing with original source material where helpful, as there were some minor errors in the text of the review.
Ketogenic Diets and Bipolar Disorder
2002: A one-month case study of a woman with unspecified, treatment-resistant bipolar disorder noted no improvement after two weeks on a ketogenic diet followed by two weeks of MCT oil supplementation. Urine testing found ketosis was never achieved.
2012: A case study of two women with bipolar II disorder who ate a ketogenic diet (one for two years, the other for three years) found that the diet was superior to the anticonvulsant/mood stabilizer lamotrigine (Lamictal) in management of symptoms. Ketosis was documented using urine test strips.
Ketogenic Diets and Schizophrenia
A 3-week mouse study showed that a ketogenic diet normalized pathological behaviors.
1965: A 2-week study of 10 women with treatment-refractory schizophrenia found a significant decrease in symptoms when a ketogenic diet was added to their ongoing standard treatments (medications + ECT). Ketone monitoring was not reported.
2009: A 12-month case study details the experience of a 70-year old overweight woman with chronic schizophrenia who was prescribed a diet limited to 20 grams of carbohydrate per day. She noted significant improvement in severe symptoms beginning only eight days after starting the diet, which consisted of “beef, poultry, ham, fish, green beans, tomatoes, diet drinks, and water.” [ Kraft and Westman 2009 Nutrition & Metabolism 6:10.] She reported complete resolution of auditory and visual hallucinations--with which she’d suffered since age seven. Ketone levels were not monitored.
Comment: This diet is best characterized as a low-carbohydrate, primarily whole foods diet. As protein wasn’t limited and fat intake wasn’t manipulated, this may or may not have been a truly ketogenic diet.
Ketogenic Diets and Anxiety
A rat study found that adding ketone supplements to a standard high-carbohydrate diet reduced anxious behavior.
Ketogenic Diets and Depression
A rat study found that a ketogenic diet reduced depressive behaviors.
A mouse study found that feeding pregnant animals a ketogenic diet reduced offspring susceptibility to depressed (and anxious) behaviors.
Ketogenic Diets and Autism Spectrum Disorder (ASD)
A 70-day mouse study found that a ketogenic diet improved behavior.
A 10-14 day rat study found that a ketogenic diet improved complex social behaviors and mitochondrial function.
A 3-4 week mouse study found that a ketogenic diet improved behaviors in ways that were different for males than females.
2003: A 6-month inpatient study evaluated the effects of a cyclical ketogenic diet (4 wks on, 2 wks off) on 30 children with ASD. Of the 18 children who completed the study, eight showed moderate improvement, and two showed “significant” improvement. Benefits appeared to persist even during the 2-week “diet-free” periods. Urine and blood ketone monitoring confirmed that all children were in ketosis.
Comment: blood ketone levels ranged from 1.8 to 2.2 mMol during ketogenic phases and from 0.8 to 1.5 mMol during “diet-free” periods, meaning that the children actually spent the entire 6-month study period in ketosis.
2013: A 14-month detailed case study of one child with ASD, epilepsy, and obesity who was placed on a ketogenic diet in combination with anti-epileptic medications, noted numerous improvements. “In addition to improvement in seizures, there was a 60-pound weight loss…as well as improved cognitive and language function, marked improvement in social skills, increased calmness, and complete resolution of stereotypies.” [Herbert and Buckley 2013 J Child Neurol 28(8)]. Ketosis was confirmed (presumably by urine testing).
Ketogenic Diets and ADHD ( Attention Deficit Hyperactivity Disorder )
A 6-month study of dogs with ADHD and epilepsy found significant improvement in ADHD behaviors on a ketogenic diet.
Ketogenic Diets and Alzheimer’s disease
This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.