Do you know what ketosis is? Not long ago it was a word that almost only professionals in the medical field were using. With the increasing popularity of low-carbohydrate diets this word has become more commonly used, some even say they eat a ketogenic diet.
It’s important to not confuse ketosis for ketoacidosis, the latter being a pathologic response to insulin deficiency in patients with diabetes.
Ketone bodies (1) are particles that the liver produces from fats (free fatty acids) and proteins and most cells can use them as energy.
When all glucose has been used up the body will utilize fat to get energy. Free fatty acids mobilized to the liver and broken down to a molecule called Acetyl-CoA, through a process named beta-oxidation.
This molecule is used in the citric acid cycle, which is working in your cells daily, to generate energy when going on carbs, but when there is no glucose some of the intermediates in that cycle are used for making glucose instead (a process called gluconeogenesis). The result is that Acetyl-CoA can’t go through the cycle and will accumulate, which sends signals to start ketogenesis – the making of ketone bodies.
These are released into the blood stream and the hungering cells will gladly use them for fuel.
In healthy individuals ketone bodies are made at a constant rate and used by the tissues. When glucose levels drop, such as during sleep or when fasting, the production of ketone bodies rise – ketosis. This is a normal physiological response.
When being on a low carbohydrate/ketogenic diet the glucose levels are kept low so that the body keeps using fat for fuel, and the fat stores will slowly melt away.
One of the ketone bodies, acetoacetate, will spontaneously be broken down into acetone if not used within approximately five hours. So if not used within that time limit it will be permanently lost for the body. This is believed to be one of the mechanisms behind the weight loss in a ketogenic diet.
The acetone is excreted in the urine and through breathing. So some people will know that they are in ketosis from their sweet and fruity smelling breath.
In fact, cells run more efficiently on ketone bodies, they are burnt more completely in the mitochondria (the energy factories of the cells), than the when glucose is the substrate. This leads to less oxidative stress and an over all lessened stress on the cells.
This is especially true for the brain, and studies have shown that elderly people with dementia can benefit from supplementing with MCTs (Medium Chain Triglycerides), that are readily rebuilt into ketone bodies and used by the brain. They seem to be neuroprotective and might be beneficial for people with neurodegenerative disorders. (1)(2) (3) (4)
Ketogenic diets was widely used in the 1920’s to treat children with difficult epilepsy. The treatment vaned when the anticonvulsant drugs was introduced.
The ketone bodies seem to be stabilizing and anticonvulsants in them selves.
There seems to be a rising interest for this field, and there are hospitals around the world use it to treat children, and sometimes adults as well. (4)