What is a ketogenic diet?
A ketogenic diet consists of low carbohydrate, moderate protein and high levels of fat. It triggers an adaptive shift towards the energy pathways normally used as a natural survival technique for humans during food restriction or fasting.Carbohydrates are broken down in the body into units of glucose, so when following a low carbohydrate diet the amount of easily accessible glucose is reduced. Fats are increased on the ketogenic diet so that they become the primary fuel, metabolized by the liver into ketones that enter the blood stream. This dietary strategy impacts on glucose and insulin levels, because insulin is released primarily in response to glucose levels in the blood, and to a lesser extent by protein intake, which is also reduced on a ketogenic diet. A ketogenic diet therefore reduces post-meal glucose and insulin peaks and helps to maintain blood glucose levels at the mid to lower end of the normal range.
However, ketogenic dietary therapy (KDT) also triggers a cascade of other biochemical pathway changes and it is this broad-spectrum effect that has led to increased interest in the potential of KDT to deliver neuroprotective and therapeutic benefits to a wide range of neurological conditions, including brain tumours. Over recent years, more published pre-clinical data and academic reviews of the potential of KDT to influence cancer metabolism have emerged, although evidence that an effect on brain tumour growth can be achieved and sustained in patients is still lacking.
Who invented the ketogenic diet?
The ketogenic diet was invented at the Mayo Clinic in America, a highly regarded mainstream hospital. It was originally developed in order to help control epilepsy, in the days before anti-convulsant medication had been invented. It is therefore primarily a medical dietary intervention, though popular mainstream media has unfortunately converted it into a number of different “fad diet” versions. The ketogenic diet continues to perform well in clinical trials for the management, and in some cases the cure, of epilepsy: primarily in children but also in adults.
Why consider the ketogenic diet for cancer?
In the 1920’s Otto Warburg first described the metabolic difference between cancer cells and their healthy tissues of origin: in other words, the different ways that they metabolise (process) nutrients in order to produce energy. He proposed that cancer cells have dysfunctional energy systems that demand vast amounts of glucose, and lack the adaptability to use other fuel sources such as fatty acids or ketones, which are produced when the body starts to use fats as its main source of energy.
Does a ketogenic diet starve our cells of glucose?
It is impossible to starve our cells of glucose, because humans cannot survive without some carbohydrates (for example, fruits and vegetables), and all carbohydrates can be broken down into glucose molecules. Glucose plays an essential part in the survival of all our cells so we cannot (and should not aim to) rid our blood or body of it completely.
However, we can influence the ebb and flow of glucose (and insulin) related pathways by adjusting the types and amounts of carbohydrate we consume in our meals, snacks and drinks. On a ketogenic diet, blood glucose levels remain within the normal range of 3.5-6.5mmol/l.
Is a ketogenic diet the only way to influence blood glucose levels?
No it isn’t. Any positive and consistent shift in your regular food choices towards a low carbohydrate diet can influence blood glucose levels, as can simply avoiding over-eating foods of all types. Moving away from sugary snacks, drinks and desserts, or simply eating more vegetables and less bread, potato, pasta, and rice in your meals is likely to lead to more stable blood glucose levels.
Physical activity, illness and medical treatments may all contribute towards elevating or moderating our blood glucose levels too.
What is a low carbohydrate diet for brain tumour management?
Between a ketogenic diet, with its very low intake of carbohydrate (less than 50g carbohydrate in 2000kcals), and a standard UK diet (perhaps 250-300g carbohydrate in 2000kcals) there is a whole range of carbohydrate modification options in between. Anything below around 100-120g carbohydrate per day is classed as a “low carbohydrate diet”.
Why consider a ketogenic diet for brain tumour management?
In 2015 the James Lind Alliance (JLA) Priority Setting Partnership (PSP), in which Brain Tumour Research was an active participant, highlighted that the number one question amongst patients, caregivers, charities, and multidisciplinary professional groups was ‘Do lifestyle factors (e.g. sleep, stress, diet) influence tumour growth in people with a brain or spinal cord tumour?”
Why explore lifestyle changes when diagnosed with a brain tumour?
All those living with primary brain tumours face an uncertain prognosis. For many, the need to actively contribute to the management of their brain tumour with its associated physical and emotional symptoms is a powerful motivator and 32-41% of brain tumour patients are reported to explore complementary therapies and consider lifestyle change to manage symptoms, and hopefully also prolong survival.
Can I get ketogenic diet therapy on the NHS?
In the UK, NHS based ketogenic dietary therapy services for adults with epilepsy are extremely limited and there is no provision for adults with brain tumours. As a result, it can be an immense struggle for those wishing to explore ketogenic diet to find appropriate information and work out whether it is the right choice, at the right time, for them.
How do I find reliable information about ketogenic diet therapy?
Since 2011, the Matthew’s Friends charitable service has provided information to many hundreds of enquirers (including many doctors and dieticians) and clinical dietetic support to around 100 self-selected adults with brain tumours who requested clinical guidance to explore ketogenic dietary therapy as a component of their brain tumour management alongside their standard treatments including surgery, radiotherapy and chemotherapy. This dietetics support service was provided free to patients, an amazing resource made possible through collaborative funding between themselves and the Brain Tumour Research Member Charity, Astro Brain Tumour Fund. Unfortunately this service has now closed because the study they were undertaking has been completed, but the Matthew's Friends website and YouTube channel remains an invaluable resource. We suggest that if you have a brain tumour, you contact the charity Matthew’s Friends (UK, Canada, New Zealand) or the Charlie Foundation (USA) for professional information about exploring ketogenic diet therapy.
Ketogenic Diet and Brain Tumour Research
The laboratory team led by Dr.Nelofer Syed at the Brain Tumour Research Centre at Imperial College, London are part of a global network of researchers investigating this long-established medical diet. Dr.Syed’s work is starting to shed light on how this high fat, low carbohydrate, adequate protein diet affects the metabolism of brain tumour cells: in other words, how it changes the way that brain tumours use nutrients to provide the energy that they need in order to grow.
Working in collaboration with experts across the UK, a clinical trial protocol is close to completion and we now need extra funds to move this forward as quickly as possible. Researchers in the US have shown that when the ketogenic diet is used alongside radiotherapy in a mouse model, brain tumours disappear from the brain, and stay away even when the mice are then moved back onto a normal diet. There is obviously a big difference between obtaining this result in a laboratory and in humans, but research in other laboratories (including those at Imperial College) also indicates that the ketogenic diet may make surgery, chemotherapy and radiotherapy work more effectively so it is vital that we explore this possibility.
To date, the laboratory work has focused on adult brain tumours, but the team at Imperial College now has the opportunity to collaborate with a research team at Phoenix Children’s Hospital, Arizona. This means that they could expand their research to include the most deadly of childhood brain tumours, Diffuse Intrinsic Pontine Glioma (DIPG).