Besides the tremendous rise in popularity of the Ketogenic diet as an excellent method for weight-loss, researchers have shown that this diet can be used to effectively treat epilepsy, type 2 diabetes, cardiovascular disease and possibly cancer.
Ketogenic diets (KDs) are very low-carbohydrate, moderate protein and extremely high-fat containing diets that induce the body to undergo ketosis. Such diets were used as early as the 1920s as a treatment of epilepsy, but the development of antiepileptic drugs lead to their abandonment. However, the tables turned around in the 1990s when researchers began to show that KDs had many more beneficial effects beyond seizure-control.
The core purpose of the KD is to induce the body into ketosis: a process in which the body starts producing alternative energy sources to glucose (figure 1). As KDs are nearly absent in carbohydrates, the body rapidly runs out of glucose reserves to supply the brain and other crucial organs. Of course, when this happens the liver begins to produce ketone bodies (the alternative energy source) that keeps your organs going so they don’t shut down!
Figure 1. The standard ketogenic diet is composed of 75% fat, 20% protein and only 5% carbohydrate. a) The minimal ingestion of carbohydrates leads to insufficient glucose levels to support vital organs. b) As a result, the body starts breaking fats into ketone bodies to fuel the organs in a process called ketosis. This typically starts to happen in most individuals after 3 days on a KD.
Most of the health benefits of the KD diet are believed to be caused by the release of ketone bodies and by the minimal need to synthesise insulin. The combination of these effects is thought to be responsible for the dramatic reduction in seizures seen in epileptic patients, improvements in cardiovascular health and reversal of early onset type 2 diabetes in some individuals. Below I will briefly summarise the scientific evidence that supports the use of KDs in the treatment of these 3 medical conditions:
The KD can be as effective for the management of epilepsy as the commonly used anticonvulsants in certain patients, but with the bonus of not having any of the drugs side effects. However, it is worth noticing that in most patients the KD will reduce but not eliminate the number of seizures and therefore they will still need to resort to taking medications as well. Nevertheless, it’s possible that epileptic patients on a KD may be able to fully control their seizures with lower doses of anticonvulsants, but we still need more research to confirm this. While the beneficial effects of this diet on the treatment of epilepsy are obvious, we don’t know much about its mechanisms of action. Researchers believe that the ketone bodies produced in individuals undergoing KDs have direct anticonvulsant effects. Additionally, they seem to reduce the excessive neuronal excitability that is common in epileptic patients, thus lowering seizure frequency.
Despite the very high fat content of the KD, many studies have shown that individuals on this diet have improved lipid profiles compared to people on other diets; meaning that they are at a lower risk of developing cardiovascular complications such as atherosclerosis. This is because the KD increases the levels of ‘good cholesterol’ known as HDL, which helps to clear cholesterol stuck in arteries and transport it to the liver where it gets degraded. Additionally, other researchers showed that this diet is capable of increasing the size and volume of LDL (bad cholesterol) particles, making them less able to deposit cholesterol in the artery walls (figure 2). These two effects are crucial in helping to reduce the development of atherosclerosis and future cardiovascular problems.
Figure 2. Ketogenic diets can reduce the risk of cardiovascular events by increasing the number of larger LDL particles and reducing that of smaller LDL molecules. It is known that larger LDL particles are significantly less harmful compared to smaller LDL as the former cannot readily cross the endothelium (inner lining) of arteries to deposit cholesterol in the artery walls.
Type 2 Diabetes
There is strong evidence to suggest the use of KDs in the management of early onset type 2 diabetes and as a preventative measure in people with early warning signs such as insulin resistance. This is a precondition to diabetes in which the pancreas is able to produce insulin but the cells do not respond to the actions of this hormone. For example, insulin is like a postman delivering parcels (signals) to houses (cells), but the person inside the house can no longer hear properly and the parcel cannot be delivered. In the case of insulin resistance, cells become unable to sense insulin and fail to take up glucose from the blood. Consequently, more glucose is taken up into the liver where it accumulates as fat (figure 3). Fortunately, the outcome of insulin resistance can be reversed early on in many people following the KD due to the very low levels of carbohydrates that are consumed (typically less than 50g/day). By completely avoiding sugars and drastically cutting down on carbs, the pancreas consequently releases very low levels of insulin to absorb that glucose. Over a few weeks of following this low carb eating pattern, the cells and tissues slowly regain their ability to respond to insulin and use glucose more readily; scientifically referred to as improvements in insulin sensitivity.
Figure 3. a) Most Individuals with early-onset or pre-type 2 diabetes have insulin resistance and a liver with more fat than is normal. b) As the body becomes more resistant to insulin, it becomes less able to store glucose inside the cells and more of the sugar ends up in the liver as fat. The enlargement of the liver is very bad news and it makes the insulin resistance get worse (a vicious circle). c) The Ketogenic diet reduces the need of the body to synthesise insulin as a consequence of the small quantities of carbs being ingested. This consequently leads to improvements in insulin sensitivity (the ability of cells to react to insulin) and reduced deposition of fat in the liver. If followed properly and done early enough, the KD can prevent and sometimes cure type 2 diabetes.
We have good evidence to support the use of KDs in the treatment of epilepsy, cardiovascular disease and type 2 diabetes, but some experts have suggested that this diet could also be an excellent strategy to ward off cancer. This is because cancer cells usually require more glucose than normal cells in order to sustain their rapid proliferation, whereas the KD could prevent this from happening as it is inherently very low in carbohydrates. Furthermore, high insulin levels appear to be involved in the activation of multiple cancer pathways and it would be logical to think that this diet would be a great way to reduce and prevent tumour growth. Nevertheless, the evidence we have now is only preliminary and larger trials must be conducted to confirm this hypothesis. Overall, the KD is a dietary approach that drives the body into ketosis in order to help with the management and prevention of several chronic diseases and may be used in the future in the management of cancer.