Chitosan, which is also known as a fat blocker or as the “fat magnet”, is a natural fiber that is extracted from the exoskeleton of some marine crustaceans. Its interest lays in the function it can perform in the digestive system, neutralizing the fats as the alimentary bolus passes, before they are metabolized.
But, what substrate is chitosan derived from? The shell that covers the body of a crustacean is composed of, among other substances, chitin (30%), which is a polysaccharide (complex carbohydrate). Its specific name is N-acetyl-D-glucosamine, and high quantities of this substance can be obtained from the exoskeleton of these invertebrates, such as prawns, lobsters, shrimps or crabs.
Previously to the chitosan extraction process, the chitin has to be completely separated from the rest of the shell’s components, which means eliminating the protein fraction that represents between 20 and 40%, the mineral material, which are basically carbonates and calcium and magnesium phosphates and that represents approximately half of the chemical composition, and the carotenoid pigments, which provides the crustaceans with the red-orange colour.
Once we have the chitin to work with, the production of chitosan takes place through a deacetylation process of this compound, which can be carried out in a chemical or biological way. In the first case, it is carried out in a very alkaline medium (like caustic soda) and in the second, it takes place thanks to the use of deacetylases, which are enzymes obtained from various species of fungi. Deacetylation, in synthesis, means eliminating the acetyl fraction from the chitin molecule, that had the nomenclature N-acetyl-D-glucosamine.
How does Chitosan work in our body?
The basis of its action mechanism in the digestive system is of an electrostatic nature. The chitosan, when passing the stomach’s acid medium, obtains a positive charge in the free amino acid groups that stick out from the N-acetyl-D-glucosamine chains. On the other side, the lipids (fats) have a negative charge provided by the COOH groups (which define the fatty acid structure). This is how the electrostatic attraction with the chitosan is produced, and consequently the gel is formed.
In order to understand the dimension of this neutralization operation, it will suffice to provide one fact: the chitosan/fat ratio, measuring the weight of both substances, can reach the 1:5 ratio.
The surface of that gel is composed of molecules of chitosan that are sequestering those of fat, that occupy the inside. It is immune to the action of intestinal and pancreatic juices, so it ends up being excreted in the faeces. The formation of the gel greatly contributes to the typical alkalinization of the intestinal environment, which contrasts with the acidity of the stomach.
To complete this method of action we must make mention to a phenomenon that is known as competitive inhibition, that is exerted on the amylase and lipase enzymes, which is due to the structural similarity between these enzymes and the chitosan.
In essence, this compound is of great use for reducing the fat absorption in the intestinal tract, consequently avoiding its storage in the specialized cells for it, the adipocytes; we must not forgot that 1 gram of fat generates 9 kilocalories, thus being the macronutrient that most energy provides, as proteins and carbohydrates provide 4 kilocalories. Thanks to this action, which graphically we could describe as a fat-blocker, chitosan also helps to reduce the levels of bad cholesterol (LDL or low density lipoproteins).
Properties and possible uses of Chitosan
One of the particularities of this natural fiber is that it agglutinates three biological properties, as it is biodegradable, biocompatible and bioactive. The combination of these properties which we could call the bio-virtues provides this substance with a very wide range of capacities, not only in the clinical field (like those described until now), but also in biochemical and biomedical applications.
The practical translation of this affirmation can be seen in the usage of chitosan in the elaboration of antibiotics, surgical stitches or cosmetics, as well as dietary supplementation.
Biomedical uses of Chitosan
In the biomedical field, the hybrid material called silica-chitosan is a very interesting option due to its excellent compatibility with the human’s body tissues, making it the material of choice to cover silk and polyglycolide stitches. And there is strong evidence for it to be this way: it accelerates the healing of a wound because it increases by more than a hundred times the permeability of the suture to oxygen, as well as limiting the development of microorganisms, minimizing this way the risk of infection.
Applied on bandages, it helps to reduce the bleeding of wounds in which an artery is involved, which tend to produce extensive hemorrhages. In this function it is a great advantage in relation to the classic gauze, to which we must be added that it is hypoallergenic and antiseptic.
It has a broad recognition within implant surgery, in combination with chlorhexidine, to reduce inflammation and pain, contributing to a lower consumption of anti-inflammatories and analgesics. It is also being administered in treatments of periodontitis and gingivitis.
In plastic surgery, it is increasingly more used as a support for the reconstruction of tissues, due to its repairing effect facing healing and avoiding scaring.
Industrial uses of Chitosan
It works as a coating agent for polyurethane paint, against sunlight aggressions, specially used for cars, furniture, and containers and packaging.
It is efficient for extraction reactions of colorants, heavy metals, radioactive isotopes and tannins form different substrates, for example to get ride of arsenic from water.
In the food industry it has found its place in different fields, such as:
The baking industry, as an emulsifier for making dough.
The drinks industry, as an adsorbent for the clarification of fruit juices and to avoid that brownish tone that apple juice is prone to acquire.
The wine industry, where it prevents alterations such as tanning and maderization of white wine with which it erases its phenolic components (chemical substances very common in plant origin foods, those in wine are called resveratrol).
In general, as a preservative in various foods because of its ability to inhibit the growth of microorganisms, bacteria (Salmonella, Escherichia, Staphylococcus, Yersinia and Listeria, all of which cause food poisoning) and fungi (Byssochiamys, Mucor and Aspergillus, the later produces the dangerous aflatoxins).
In relation to this last one, an interesting fact is that chitosan stimulates the synthesis of phenolic compounds in peanut seeds. These behave as inhibitors of the fungus Aspergillus flavus, thus reducing the risk of aflatoxin production.
Its antimicrobial action is based on modifying the permeability of the cell wall of these germs at the bonds between positive ions of the chitosan and the negative ones of the bacterial wall. It is known that its presence when storing egg mayonnaise at room temperature, reduces the amount of microorganisms of the genera Lactobacillus and Zygosaccharomyces that cause alterations. And in sausages it is used to reduce the amount of nitrites, which is an excellent advantage, as these have a certain carcinogenic capacity.
Agricultural and Environmental uses of Chitosan
Contributes to increase the production performance and provides protection against external agents, especially against infections caused by fungi.
Intervenes in the water filtration process, getting rid of contaminating substances for its purification.
And it is efficient as a coagulating agent or flocculant in the primary treatment of residue waters, eliminating substances that are in a colloidal state and that would take a long time to be eliminated via sedimentation.
Clinical benefits of Chitosan
Chitosan is a natural way of reinforcing the immune system, integrated by two facets: the humoral and the cellular immunity. The first of which is represented by the synthesis of antibodies, while the second is exerted by a group of cells, the main ones being T and B lymphocytes.
Chitosan exerts a positive influence on both of them, but especially remarkable is its activation of the NK (Natural Killer) cells, whose function is to specifically attack cancer cells; This activation makes chitosan ten times more energetic than other cancer treatments.
There are reputed studies that have come to show that chitosan can balance blood cholesterol levels, especially LDL or "bad cholesterol." It should not be forgotten that hypercholesterolemia (elevated blood cholesterol levels) is one of the main risk factors for cardiovascular and cerebrovascular disease (stroke).
It is also known to be hypotensive, that is, it reduces blood pressure, it improves calcium assimilation (which is especially interesting for those suffering from osteoporosis), it controls and eliminates the Helicobacter pylori bacterium that triggers gastroduodenal ulcers in the stomach and also works as a support for the treatment of anemia.
Among its many benefits we can not overlook its use to avoid infections in teeth and gums, collaborating even, as previously mentioned, in the recovery of tissues after plastic surgery.
On the other hand, medical studies have been published that reflect conclusive arguments about the potential of chitosan as a supplement in the treatment of people with Crohn's disease (a chronic inflammatory process that is usually established in the intestinal tract, more frequently in the last sections).
The key role of chitosan: a powerful slimming agent
Due to it being considered a natural fiber of excellent biological quality and having an extraordinary capacity of absorption of fats, its main and most known application is as a dietary supplement in weight loss processes. But it is necessary to realize that the fact of planning a consumption of chitosan does not guarantee the loss of weight, as it requires to be combined with a good diet and the regular practice of exercise so that the wanted results are obtained. Chitosan has no influence on carbohydrates.
Each ingested gram of this product sequesters about eight grams of fat. If we consider that, as we will see below, a daily dosage of three grams is recommended, we would be eliminating between twenty and twenty five grams of fat. While it is true that it is a major task, it is also true that we should avoid falling into a false sense of security and depositing all the responsibility of restricting dietary fats in this product, which could lead to an overconsumption with the consequence of gaining weight.
The ingestion of two grams and a half of chitosan before a meal that contains fats, makes it possible to divert from the metabolism an amount of these which would be equivalent to between 140 and 180 kilocalories.
Some side effects of Chitosan
When considering the effects of chitosan as a weight loss enhancer, we should take into account an important fact: the problem of using chitosan or any other blocker can be that the supply of both essential fatty acids and fat-soluble vitamins (A, E, D and K) may be lower than the nutritional recommendations.
It should also be noted that there are some adverse effects in pregnant women, which basically mean that there is a slowing down of fetal growth.
Some other side effects described after ingesting chitosan are confined to the respiratory system, such as a compression sensation in the jaws and chest, but also to the skin (itching, rashes and dermatitis) and recurrent intense headaches.
Finally, those people who are allergic to shellfish can (and indeed, probably will) react adversely to chitosan. The possibility, albeit remote, of being a victim of any of these side effects, makes it advisable to take the precaution of consulting a specialist before taking chitosan.
How to take chitosan
To obtained the desired results, the diet should be restrained in carbohydrates and combined with abundant liquid to facilitate the excretion of the fats that are trapped in the faeces.
Chitosan can easily be found in herbalists, pharmacies, parapharmacies and supermarkets, as well as online platforms (like HSNstore). There is quite a wide selection, the most common formulas being those that have between 200 and 400 mg per capsule. The general recommended dosage is around 2500mg a day, spread out in the three main meals of the day. To take it correctly, it is preferable to do so 15 minutes before the meal with 2 glasses of water.
Regarding the length of the treatment, it is advisable to prolong it for at least twelve weeks, less than this period and the effects may go unnoticed. At the same time, it is dangerous to prolong the treatment excessively (over fifteen weeks) as we may notice the reduction in the assimilation of the previously mentioned nutrients. Nevertheless, the most sensible option is to consult a doctor to know the quantity to take. To not suffer side effects, it is best to not ingest inconvenient doses and durations.
Another use entails applying chitosan, provided as a powder or in chewing gums, on gums with the purpose of fighting periodontal diseases or gum inflammation.
Some useful combinations of Chitosan
Within a weight-loss program, adding supplements that act as an inappetent may result to be very effective, such as some algae (spirulina and fucus), or adding one that produces a metabolic “stress”, like red tea or horehound (plant with very positive effects on the digestive system, gallbladder and liver), among others.
Combining with vitamin C (frequently you can find this mix in commercial products), enhances the reduction of fat absorption.