MYTHS ABOUT KETOSIS

MYTHS ABOUT KETOSIS

THE MEANING OF THE WORD THAT GETS LOST AMONG THE CROWD OF OVER-INTERPRETATIONS

Ketosis is a recently fashionable word that reaches an increasing number of people interested in nutrition, health, and human physiology. Along with the spread of the word due to the boom on ketogenic (ketogenic) diets, its meaning undergoes a deliberate or unconscious transformation. Ketosis is mistaken as a dietary system or lifestyle. Some people reserve ketosis only for specific diets or call certain nutrition strategies for athletes as ketosis. All these homonyms are created to create some elitism by using the strong-sounding word "ketosis", to distinguish themselves from thousands of other people dealing with nutrition. Still, others use an altered meaning of the word "ketosis" for marketing and promotional purposes. Many people think

DEFINITION OF KETOSIS AND ITS PRACTICAL SIGNIFICANCE

Physiology textbooks clearly define ketosis as a higher-than-normal concentration of ketone bodies (acetoacetic acid, beta-hydroxybutyric acid, and acetone) in the blood. The normal level is considered to be about 0.1 mmol/dl, and the state of ketosis is a much higher level of ketone bodies. We deal with ketosis regardless of how this condition was caused, the sufficient condition here is the appropriate level of ketones in the blood. The state of ketosis does have some metabolic consequences, but ketosis itself remains ketosis in the physiological sense of the word. It is very important to use one meaning of the word when referring to ketosis. When communicating with other people about health, nutrition, or physiology, you should use precise meanings of the words.

MYTHS ABOUT KETOSIS AND THE KETOGENIC DIET

There is a lot of untrue information circulating on topics related to ketosis and the ketogenic diet. The most common reason for duplicating untrue information is an incomplete understanding of the phenomena the information relates to. Below, I will try to explain some of the common mistakes that relate to ketosis.

KETOSIS AND BETA-OXIDATION OF FATS.

Ketosis is not equivalent to optimal beta-oxidation of fats. Ketones are not formed in the process of beta-oxidation of fats, but from the final product of this, i.e. acetyl coenzyme-A. Acetyl coenzyme-A can also be formed from certain amino acids. You can be perfectly adapted to obtaining energy from fatty acids, without developing ketosis at all. Ketones can also be converted into fatty acids, and excess energy, even in the presence of ketosis, does not cause fat loss. Therefore, it is not valid to say that ketosis would be a state of optimal fatty acid burning.

KETONES DO NOT ONLY SERVE AS AN ENERGY SOURCE

It is well known that ketone bodies (β-hydroxybutyrate, acetoacetic acid, and acetone) serve as an energy source. However, the ketone bodies have their place in anabolic processes. Ketone bodies serve as substrates for the production of cholesterol, fatty acids, and complex lipids, among other things. In the early postnatal period, ketones are a more preferred substrate than glucose for the production of phospholipids and sphingolipids due to the demand associated with increased brain and myelination of nerve fibers. In the above-mentioned period, acetoacetic acid is a better substrate than glucose for the production of phospholipids in the lungs. These phospholipids mainly serve as a pulmonary surfactant. Ketone body processing enzymes are found in all tissues of the human body. The enzyme involved in the synthesis of cholesterol from ketones shows many times higher activity in the liver than in other body tissues.

KETONES IN THE URINE

Ketones are excreted in the urine because the kidneys are not the most efficient at filtering them, not because the body is unable to use ketones efficiently. Ketone bodies dissolve in water and therefore end up in the urine like many other substances, such as, for example, water-soluble vitamins. The presence of ketones in the urine is not a symptom of deliberate excretion of ketones and it is because ketones are "leaking" into the urine. Ketones are not as valuable and expensive to synthesize as glucose, so there is no need to carefully filter them. The fact is that the kidneys' efficiency at filtering ketones increases over time and they may no longer be present in the urine in the amount detectable by the strips.
Ketones (acetone) are also excreted through the lungs, which is also not a symptom of inefficient use in the body.
The ketone body measured in urine is acetoacetic acid. However, this is not the only type of ketone that is excreted in the urine. Beta-hydroxybutyrate is also found in the urine - but in a much smaller concentration.
I also came across the opinion that the body excreted ketones in the urine to avoid ketoacidosis (sic). This is absolutely not true. Ketones stimulate the pancreas to produce insulin, which inhibits ketogenesis and thus protects the body against ketoacidosis. Ketoacidosis can develop in people who suffer from an inherited deficiency of ketone-converting enzymes and in people who are deficient in insulin.

UTILIZATION (CONSUMPTION) OF KETONE BODIES IN THE INITIAL STAGE OF KETOSIS

A common myth is that when ketosis occurs, the brain or other tissues do not start using ketones immediately. There is no justification for this in the case of the brain, for example. The increased influx of ketones to the brain occurs immediately after the onset of ketonemia, i.e. an increased level of ketones in the blood. There is no fixed time limit after which a mysterious adaptation takes place, and only then the ketones that circulate in the blood could be used for energy and other purposes.
A common example of immediate ketone consumption is exercise ketosis. The concentration of ketones in the blood increases as liver glycogen is depleted. The liver's priority during exercise is glucose production, oxalacetic acid, which feeds the citric acid cycle, is directed to the gluconeogenesis process so that an excess of acetyl coenzyme A accumulates in the cells, which then feeds ketogenesis. The phenomenon of exercise ketosis occurs even in players who eat high carbohydrates. Skeletal muscles and the heart muscle can use ketones as an energy source right away.
The fact is that the ability to utilize ketones increases as ketosis lengthens, but this does not happen abruptly and does not mean that the body cannot use ketones in the first days of ketosis. The ability to use ketones is encoded in man as is the ability to produce them. There may be cases of people who have trouble using ketones, but are deficient in, most often congenital, ketolytic enzymes. Such people most often develop ketoacidosis.
Anyone with pathological ketosis has the ability to use ketones.

INUIT ARE NOT AN EXAMPLE OF LONG-TERM KETOSIS

Much of the Inuit population (unfortunately called Inuit because the name is offensive to them) has a mutation in the CPT1A gene, which encodes a protein responsible for transporting long-chain fatty acids to the mitochondria. The P479L mutation practically prevents the transport of fatty acids by the mechanism of carnitine palmitoyltransferase (CTP1). Probably, for this reason, Inuit with this mutation are not able to produce more ketones, i.e. as much as we can produce. Although this mutation Inuit high-fat cope perfectly. For this reason, the Innuici is not a good model of long-term ketosis, but they are an example of people in whom beta-oxidation of fatty acids occurs without problems and does not develop ketosis.
Hopefully, I have cleared up some of the doubts surrounding ketosis. There are also a lot of myths about the low-carb diet itself. Perhaps I will pay attention to them in a future post.

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