Ketone Bodies: Definition, Synthesis, and Physiology

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What are Ketone Bodies?

Ketone bodies can also be generally called as ketones. These are the substances that is produced by the liver while performing the process of gluconeogenesis.

Gluconeogenesis, is one of the vital process that runs in our body, during fasting or when the body starves. At these times our body creates glucose by its own.

Generally, there are about three ketone bodies that is being produced by the liver, namely acetoacetate, Beta-hydroxybutyrate and the acetone.

These are the compounds that are usually present in a healthy individual and supplements energy to the cells of the body when the amount of glucose is absent or it may be low in cases of dieting.

Generally, fatty acids undergo the process of Beta-oxidation in the liver, which makes the mitochondria to Generate high amount of energy for the body by using the three compounds which are known as Ketone bodies.

These bodies are basically water soluble and they do not require a lipoprotein for transporting them across the membrane.

Ketone bodies are one of the lipid molecules which contains carbonyl groups being attached to the two -R groups.

Ketone Body Synthesis

Usually when we over take the foods that is rich in carbohydrates, our body starts storing excess of glucose in our body in the form of fats and other building proteins, which are the things that especially makes us to grow. This state of our cells is known as absorptive state.

In case, when we fast or starve ourselves, the glucose levels in our blood starts decreasing suddenly. This makes our body to enter into the postabsorptive state. In postabsorptive state our body again converts the stored fat into fatty acids and glycogen, which are further converted into glucose and are used by our body cells for breaking up the amino acids and synthesing energy molecules.

When glucose is stored in the form of glycogen and converted back into the same form as vice versa, liver plays a major role in storing it. Once these storages are depleted, our body cells take up the other form for getting out the energy that is needed by the body.

We all must know that brain losses its function without the adequate amount of energy that is being supplied to it. So, the liver always ensures, whether the brain is getting enough energy, thus the process of converting the glycerol, pyruvate and the lactase into glucose by the liver is known as glucogenesis, during this process, two ketone bodies are formed namely acetoacetate and beta-hydroxybutyrate.

These ketone bodies are released into the blood stream along with the glucose to feed the brain. While performing this process, all the other organs and muscles gets shifted to the fatty acids for getting their energy thus conserving the glucose for the brain. As brain needs energy only from the glucose. This process is known as glucose sparing, which is also considered as very important for all the animals that undergoes long duration of fasting or those which starves.

Though we say that brain opts for glucose for the source of energy, but not for so long days. After 4 days of full starvation, and absence of glucose in the body, the brain swifts for energy source from the ketones. This situation greatly increases the time taken by the organism to starve without food which results in many side effects.

At this time if food is not taken by an organism to replenish the supply of glucose, Ketone bodies build up. These ketone bodies are usually the one which is being removed by the kidney during filtrations.

If they are over built due to these starvations then it leads to severe damage of the kidney. Further ketone bodies break into its units and it results in the formation of the acetones.

Acetone is considered as one of the volatile and a highly reactive substance. When this acetone builds up in the blood it lowers the pH of the blood and this condition is known as acidosis.

Acidosis makes all over body tissues to get irrespective of its function and it also makes the cells and tissues to mess up with all the enzymes of the body, depending of the pH balance.

Ketoacidosis or acidosis is caused by excess ketone bodies. This condition if left untreated it leads to coma and even death. 

Ketone Bodies vs Keto Diet

Keto diet is becoming a lifestyle adaptation by many of the people who choose it as their platform for losing weight. But actually, keto diet is not usually recommended by the researches, as this diet involves the reduced amount of glucose to be supplied to the body which results in many of the effects as listed above.

Even if keto diet is considered as an effective way to lose weight, it should be done under the supervision of the physician as in many of the cases, it leads to formation of kidney stones, brain issues etc.

Ketone Bodies Citations


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