From Low GL to Ketogenic 

At Food for the Brain, one of the key messages we enforce is the importance of eating a diet that’s low in glycemic load, which in other words means avoiding refined sugars and flours, and swapping them for wholegrains, fibre-rich legumes and starchy vegetables. These sources of carbohydrates release their sugars gradually instead of all at once, which not only helps to sustain energy levels throughout the day, but also positively impacts the brain, which is sensitive to fluctuating blood sugar levels. Research in the last 10 years has exploded on the role that insulin resistance and insulin deficiency (caused by diets high in refined sugars) plays in cognitive decline and the development of Alzheimer’s disease, so much so that scientists have begun to label Alzheimer’s as a type 3 diabetes or diabetes of the brain. Switching to a low GL diet is relatively easy, but what about those diets that go as far to say that eliminating carbohydrates almost completely from the diet, such as in the ketogenic approach, is more efficient in improving brain health?

What is the Ketogenic Diet? 

The ketogenic diet was first introduced by physicians in the 1920s for the treatment of childhood epilepsy, after scientists discovered that during periods of fasting the body begins to use fat as a source of energy instead of glucose, which resulted in less seizures in patients. Two specific compounds were found to be produced in the body during fasts – acetone and beta‐hydroxybutyric acid – now known as ketones, which are a byproduct of fat breakdown in the liver and are used by the body as energy when there is no more glucose available. During this research study, scientists discovered that following a diet with moderate protein, minimal carbohydrate and high fat (roughly 60%-80% fat,15%-35% protein, 5% or less carbohydrates of total daily caloric intake) could also lead to the production of ‘ketosis’, where the body begins to use ketones as energy instead of glucose. Improvements in behaviour and cognition were also reported, which set the tone for future trialling of the ketogenic diet to improve brain health for a variety of conditions.

Why is ketosis good for the brain? 

Research on the ketogenic diet in the past few years has increased, in particular its therapeutic application in symptoms related to neurological disorders and mental health, as well as in treating conditions such as type 2 diabetes. Whilst the exact mechanism of how ketones improve brain health is still unclear, ketones used as fuel for the body have shown to increase neuronal growth factors (meaning neurons are able to regenerate and proliferate), reduce brain inflammation and oxidative stress, strengthen signals between synapses and enhance mitochondrial respiration (a process of energy production that takes place in our cells). 

Human studies are, however, minimal in researching the value of the ketogenic diet in improving brain health, with most scientific studies still being focussed on animals. In addition, many studies use supplements such as MCT (medium-chain triglycerides) capsules to induce the production of ketones in the body, which may be due to the fact that following a ketogenic diet and monitoring large groups of people is difficult. MCTs are fatty acids that do not require bile to be digested, instead they go directly into the liver and are able to feed into the mitochondria of the cells without needing L-carnitine to shuttle them across the mitochondrial membrane, unlike other fatty acids. This translates as an immediate energy source, functioning much like simple carbohydrates do but without the impact on blood sugar levels.

There has been some positive results using supplements such as MCT. For example, in a 90-day randomized, double-blind, placebo-controlled, parallel study of 152 people with mild to moderate Alzheimer’s Disease, a daily MCT supplement was given. Participants were asked to take a cognitive test at 45 and 90 days using the ADAS-Cog scale and patients taking the MCT supplements showed significant improvement in the cognitive test, unless they carried a gene called ApoE4, which is associated with a higher risk for developing Alzheimer’s disease.

Can the ketogenic diet help with mental health symptoms? 

The majority of studies are animal-based, which despite demonstrating positive results, there is still a long way to go with regards to understanding the direct mechanism of how the ketogenic approach alters brain chemistry and its value in long term improvements to mental health. One interesting study in children with medication resistant epilepsy, showed how following the diet had a significant impact on the neurotransmitters, dopamine and serotonin, both of which are implicated in depression and anxiety. The children followed the diet for a period of 3 months, neurotransmitters were measured before and after in their CSF (cerebrospinal fluid). Metabolites of both serotonin and dopamine had significantly reduced after following the ketogenic diet, demonstrating that these neurotransmitters were being utilised more efficiently in the brain.

There have also been some case studies that encourage further research into this field. In one particular study, a significant improvement in symptoms were reported. 2 women with bipolar disorder type II followed the ketogenic diet for an extended period of 2 and 3 years respectively. Only one measured their macronutrient composition, which was roughly 70% fat, 22% protein, and 8% carbohydrates, and ketones were measured in the urine. Both women reported subjective improvement in mood stabilisation as well as an overall improvement of their condition, which surpassed the effects of medication.

Is it safe to follow the ketogenic diet unsupervised? 

Research to date suggests that the ketogenic diet is safe for most people, however, it has a large impact on the body and for this reason we would always advise people to seek expert guidance before trying it, especially if they are are on medication of any form. According to Dr Georgia Ede, a Harvard-trained psychiatrist and nutrition consultant, in the first couple of months of the ketogenic diet your body goes through profound shifts in chemistry, which may affect the metabolism of medication, as well as significant mood changes. Here is a list of medications related to common mental health conditions and how they can be affected by following the ketogenic diet.

Whilst the emphasis is on achieving the correct amount of macronutrients (ratio between carbohydrates, protein and fat) to encourage ketosis, the nutrient value of food should also be taken into account in order to prevent deficiencies. For example, many may be drawn away from having a significant amount of vegetables on the keto diet,  due to the fact that some can be high in carbohydrate content. However, it is critical to ensure enough fresh vegetables whilst undertaking this approach to prevent falling short on micronutrients that play an important role in our cellular health and preventing oxidative stress. In addition, eating the right protein and fat sources is also very important, as processed meat and hydrogenated or refined oils can leave us more vulnerable to long-term health problems such as cardiovascular disease.

Low GL or Keto?…

Whilst research on the ketogenic diet and brain health has showed and continues to show some positive results, it’s still very much in the early stages and a lot needs to be understood about the underlying mechanism of how ketones improve biomarkers associated to poor mental health and the long term impacts of this dietary approach. Eating a diet that’s low in glycemic load may be an easier, more accessible way of switching to a way of eating that has little impact on blood sugar levels and encourages a healthy insulin response, which has shown to have a positive impact on cognitive health. If you’d like some more support on how to switch to a low GL diet, please click below for our mini guide.

Low GL Diet

Where to go for support…

We believe that following a ketogenic approach should be under the guidance of a nutrition professional, to ensure you’re still getting the right nutrients and that the diet is tailored to your individual needs. If you’d like to reach out to a qualified nutritional therapist to guide you through this process, BANT (British Association for Nutrition and Lifestyle Medicine), have a search engine for practitioners that are local to you. Our not-for-profit clinic, the Brain Bio Centre also have a team of therapists that specialise in brain health and can discuss the best approach for you individually. If you’d like to get in touch to find out more about their services, please call 0208 332 9600 or visit their website here Brain Bio Centre.

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