The growth of cells in the body is tightly regulated.
Various transcription factors and molecular mechanisms ensure that cells only grow and divide when appropriate.
But cancer cells are in many ways different than other cells.
Something in the regulatory mechanism breaks and they start growing and dividing rapidly.
The cancer cells start hoarding energy from the blood, then they manipulate their surroundings to support their rapid growth.
One interesting fact about the metabolism of cancer cells, is that most of them rely solely on glucose from the blood as a source of fuel. This is called the Warburg effect.
Cancer Cells Lack Metabolic Flexibility
Normal cells of the body have a certain metabolic flexibility. If insulin is low, they can start using either fatty acids or ketone bodies to provide energy.
Most cancer cells are unable to do this. They need glucose.
This has lead to speculation about whether a carb restricted diet can reduce the available fuel for the cancer cells, partly starving them and perhaps being of use alongside other more conventional therapies like radiation and chemo.
But it’s important to realize that even though dietary intake of glucose is low, the body will still make plenty of glucose via gluconeogenesis and cancer cells are particularly efficient at “stealing” the little glucose available from the blood.
So a carb restricted diet won’t starve the cells in this way.
It might reduce their available fuel slightly, while still providing plenty of energy for the other healthy cells of the body via fatty acids and ketones.
Other Potential Mechanisms
Low-carbohydrate diets also lead to lower levels of circulating hormones Insulin and IGF-1.
This may cause the cancer cells to get less signals to grow and divide.
Additionally, ketone bodies have been shown to inhibit the growth of cancerous cells in culture (1).
It is an interesting concept and ketogenic diets are currently being studied as potential treatments for cancer alongside other conventional treatments.
Current Research on Low-Carb, Ketogenic Diets and Cancer
There was a pilot study in 10 advanced cancer patients published last October. The patients did a very low-carb, ketogenic diet for 28 days.
According to a PET scan, 4 of the patients continued to have progressive disease, while 5 remained stable and 1 had a partial remission.
The patients who had the best metabolic response to the diet (that is, lowest insulin and highest ketone levels) saw the most improvement (2 – .pdf).
A Case Report of Two Girls With Brain Cancer
In 1995, a case report of two girls with brain cancer was published.
After 7 days on a ketogenic diet, blood glucose levels decreased and glucose uptake at tumor site decreased by 21,8%.
One of the girls had significant improvement in symptoms and her disease did not progress for the next 12 months (3).
Quality of Life in Cancer Patients
In a pilot trial of 16 advanced-stage cancer patients, a ketogenic diet did improve quality of life and stopped the progression of cancer for the 5 patients who completed the 12 week study (4).
What About Prevention?
Many types of cancer are associated with other diseases of civilization like obesity and diabetes.
Given that low-carb diets can in many cases drastically improve and even cure some of these diseases, it doesn’t take a big stretch of the imagination to see how this diet may reduce chances of developing cancer later in life.
Elevated blood sugar and insulin levels, high circulating IGF-1, these are all risk factors for cancer and are all improved on a low-carb, ketogenic diet.
This Needs a Lot More Research
Cancer is a nasty bitch. You can cut it away, radiate it and overload it with poison, but somehow it often still manages to survive and spread.
Ketogenic diets may turn out to be a useful weapon in the arsenal against this foul disease, but it is definitely premature to make any recommendations based on current research.