How did the ketogenic diet start?
Ketogenic diets have been around for over 100 years, during which they have evolved from a medical treatment for epilepsy to a contentious weight-loss fad diet. Ketogenic diets have regained popularity as scientists began exploring whether they could be repurposed to treat psychiatric disorders.
In the 1920s, ketogenic diets were initially used to reduce and prevent seizures in children and adults with treatment-resistant epilepsy. Ketogenic diets gained popularity as a tool for weight loss in the 1970s after Dr Robert Atkins published his now-famous dietary programme, the ‘Atkins Diet’, which is a modified version of the ketogenic diet. Ketogenic, Atkins and other low-carbohydrate diets continued to become increasingly popular throughout the 1990s. During the last two decades, a number of celebrities endorsed the ketogenic diet as a weight loss ‘miracle’, while the public filled internet forums with anecdotal success and horror stories about their experience of the ketogenic diet. This increased media coverage led to the ‘keto diet’ being the most googled diet trend in 2018. Understandably, the exaggerated claims and celebrity endorsements led many people to consider ketogenic diets as nothing more than another extreme weight-loss fad. However, this also led the scientific community to show a renewed interest in ketogenic diets as a potential treatment for mental health conditions. Over the last 20 years, a rapidly increasing number of studies began investigating whether ketogenic diets could be used to treat conditions such as schizophrenia, depression and bipolar disorder.
Currently, it’s still unclear whether ketogenic diets offer any substantial benefits for long-term weight loss compared with other more widely researched diets, such as the Mediterranean diet. For a more comprehensive overview on the evidence for ketogenic diets as a weight loss tool, readers are directed to read X or X. To read more about the history of ketogenic diets in mental health research, you can skip ahead to ‘Ketogenic diet research in medicine and psychiatry’.
Ketogenic Diets in Medicine and Psychiatry
Many people are surprised to learn that ketogenic diets have been used since the 1920s as a treatment for drug-resistant epilepsy. The discovery that ketogenic diets could reduce or prevent seizures in patients with severe epilepsy (that didn’t respond to medication) led to many studies investigating the role of ketones as a new avenue to treat symptoms of mental health and neurological conditions.
Why are ketogenic diets being used in psychiatry?
Ketogenic diets can change how cells inside the brain use energy, which we know can prevent seizures in some patients with epilepsy. Scientists are currently investigating whether ketogenic diets can have the same effect on improving brain function in certain mental health conditions, such as schizophrenia, depression and bipolar disorder.
A recent review, published in the International Journal of Neuropsychopharmacology, suggested that ketogenic diets seem to improve brain function and cognition by targeting the underlying biological mechanisms linked to mental health symptoms. Studies of humans and animals have found that high-quality ketogenic diets can lead to a number of health benefits, including:
- Reduced inflammation
- Improved oxygen utilisation
- Changes in the gut microbiome
- Regulating key neurotransmitters
These biological mechanisms have all been proven to have an effect on brain function and mood. For example, patients with mental health conditions tend to have higher levels of inflammation in their body and brain compared with healthy individuals, and the level of inflammation seems to correspond with symptom severity. If ketogenic diets are capable of addressing the biological cause of mental health symptoms, such as reducing inflammation, this could potentially lead to a huge breakthrough in how we treat psychiatric disorders.
Microbiome and keto reviews
Reduction in beneficial gut bacteria (bifidobacterium) and increase in harmful gut bacteria (ecoli) linked to ketogenic diet: Book chapter Diet & Mental Health in Microbes and the Mind: The Impact of the Microbiome on Mental Health. Senior author Felica Jacka from the Deakin Food & Mood Centre.
Possibly helpful for Autism and Schizophrenia. Some patients may show more benefit depending on baseline blood ketone levels and gene expression. Towards Tailored Gut Microbiome-Based and Dietary Interventions for Promoting the Development and Maintenance of a Healthy Brain
Ketogenic diets for treatment-resistant mental health conditions
Ketogenic diets might be particularly beneficial for patients with severe or treatment-resistant psychiatric disorders, which are also known as neuro-progressive disorders, according to a recent scientific review published in The International Journal of Neuro-Psychopharmacology. Schizophrenia, depression and bipolar disorder are increasingly being recognised as neuroprogressive disorders, meaning that damage to the structure and function of the brain worsens over time. As the damage to the brain progresses, symptoms become more severe and difficult to treat. For example, damage to the brain is known to cause cognitive decline and increase vulnerability to stress. Unfortunately, some patients go on to develop treatment-resistant mental health conditions with severe symptoms that show little to no improvement from conventional medical treatments.
Can ketogenic diets improve cognition?
The potential for ketogenic diets to improve brain function provides an exciting new avenue of treatment that could treat or prevent cognitive decline in patients with severe or treatment-resistant mental health conditions. Cognitive decline is a normal part of ageing that leads to difficulties in storing and retrieving memories, learning information and decision making. However, the speed and severity of decline is accelerated in severe mental illness, making it much more difficult for patients to care for themselves and live independently. Very few psychiatric medications are able to target the underlying cause of cognitive decline, meaning that cognitive symptoms are significantly more difficult to treat and manage than other symptoms (such as low mood or anxiety).
Can ketogenic diets treat other comorbid conditions?
Mental health conditions are rarely seen in isolation; meaning, that if you struggle with a diagnosed mental health condition you are more likely to have another chronic condition, such as diabetes, cardiovascular disease, or obesity, among others. Once again, science shows that common neurochemical abnormalities are found in both mental health conditions and metabolic conditions (such as cardiovascular disorders, heart disease, obesity and diabetes). Some of the trademarks that these conditions share include: glucose hypometabolism (otherwise called insulin resistance), oxidative stress, inflammation of the periphery and brain, and dysfunction of the mitochondrion (the powerhouses of the cell responsible for energy production in the body).
What are the limitations in ketogenic diet research?
Currently, the evidence for ketogenic diets in treating mental health conditions is limited due to a lack of large clinical studies with long follow-up periods. Although there is increasing evidence that the ketogenic diet can be helpful for some people, unfortunately, we don't have a way to predict which conditions or individuals would respond to it. Results of studies can also vary greatly depending on how the study was designed, and individuals can respond differently depending on their age, hormones, gender, physical health, microbiome and diet quality. With the sample sizes of studies becoming larger, scientists will soon be able to identify which patients would be most likely to benefit from going on a ketogenic diet.
Do ketogenic diets have any risks?
Scientific reviews have found that ketogenic diets can lead to developing vitamin and nutritional deficiencies in some people over time. Due to the limited number of long-term studies, there are concerns about the safety and ease of maintaining a strict ketogenic diet for a long period of time. Ketogenic diets have also been associated with an increased risk of nutritional deficiencies (although this depends on how they are managed), and the way in which individuals respond to the diet seems to vary dramatically. Specifically, reducing carbohydrate intake in favour of fat and protein may lead to people swapping healthy plant-based foods and wholegrains for processed meats and certain saturated fats. Reducing your intake of vegetables, fruits, legumes and wholegrains increases the risk of vitamin and mineral deficiencies, and the lack of fiber can reduce beneficial gut bacteria in the microbiome. Diets that are high in processed meat and saturated fat are associated with increased inflammation and risk of developing conditions such as: diabetes, cardiovascular disease, some cancers, and Alzheimer’s disease.
Could ketone supplements replace ketogenic diets?
Scientists have also begun investigating whether taking ketones as a supplement (called "exogenous ketones") can improve symptoms instead of the ketogenic diet itself.
Dr Chris Palmer’s theory on ketogenic diets for mental health:
Dr Chris Palmer, a Harvard Medical School Psychiatrist and one of the earliest pioneers of ketogenic diets in psychiatry, theorised that ketogenic diets could target the underlying cause of mental health symptoms. Dr Chris Palmer theorised that the neurotransmitter and brain abnormalities seen in mental health conditions could be caused by underlying mitochondrial dysfunction. The mitochondria are famously labeled the “powerhouse of the cell,” as they are largely responsible for producing energy for cells in the human body. Mitochondrial dysfunction means that the cell energy is not being produced efficiently or effectively, leading to impairments in brain function, emotional regulation and stress responses, all of which are observed in psychiatric disorders.
When the brain uses ketones as an energy source, these ketones seem to be capable of reversing the process of mitochondrial dysfunction. When the body enters a state of ketosis, other cells also begin to use ketones rather than glucose as an energy source. Ketones also seem to have a positive impact on the body’s metabolism and immune system by lowering inflammation, augmenting antioxidants, and removing the presence of excessive glucose. Preclinical studies of animals have found that ketogenesis leads to a reduction in oxidative stress and inflammatory markers, leading to better regulation of neurotransmitter systems.