I don't know when hair has become one of the most important items in the self-image management of our young people in the new era, we have been committed to raising a thick and beautiful hair, and we have gone further and further on the road of "how to prevent baldness", but we have ignored the deepest essence of hair - it is protein.
Some people may be curious, why can't hair be eaten as a protein (the stomach can't digest it)? And the cat licks its hair every day, and it licks it into the stomach, how can its hair be eaten? Sometimes the small ball of hair that vomits and vomits, is it because the stomach can't digest the hair, or is there too much hair, and the stomach can't digest it and can only spit it out?
Don't worry, let's take our time.
Hair from macro to micro
Let's start with a macro look at human hair. Hair, as the name suggests, refers to the hair that grows on the head. Hair, in addition to adding beauty, is mainly used to protect the head. Fine, fluffy hair is elastic to resist lighter bumps and can also help the evaporation of sweat from the head. Of all the hairs in the human body, hair can grow the longest and the fastest.
Hair has no sense of pain or touch, is not a human organ, and does not contain nerves and blood vessels. The pain felt by pulling the hair is due to irritation of the tactile nerve on the scalp.
Biological hair is a general term that includes tissues such as hair follicles below the epidermis of the scalp in addition to the hair shaft that exposes the epidermis. At the base of the hair follicle, epidermal cells divide and differentiate, growing hair shafts. The sebaceous glands secrete sebum, which provides natural protection for the hair.
Each hair is composed of an epidermal scale, cortex, and medulla layer. The epidermal scales are the outermost layer of the hair and are usually translucent or colorless, so it allows the natural hair color to shine through, the cortex layer makes up 80% of the hair, where the natural pigment is deposited, and the medulla layer is located in the center.
Hair is a complex fiber, α-keratin is the most important component of hair fiber, and the rest of the components include lipids, water, pigments and trace elements. Speaking of which, there is another issue that has puzzled the French to this day, because Napoleon's hair contains arsenic in higher than normal values, and it is still uncertain whether Napoleon died of poisoning or stomach cancer.
It's also worth mentioning here that all vertebrate hair is made up of α-keratin, and cat hair is no exception.
The secret of not eating hair lies in this miraculous keratin. And the so-called "eating hair" of cats is not what we imagine to eat.
The microscopic process of digesting proteins
Before we talk about keratin, let's briefly review the process by which the human body digests and absorbs protein. We all know that proteins are not easily absorbed as macromolecular substances that are not digested or absorbed. Generally, food proteins can only be absorbed after hydrolysis into amino acids and small peptides. Since saliva does not contain enzymes that hydrolyze proteins, the digestion of food proteins begins in the stomach and ends in the small intestine. During this period, under the continuous action of gastric acid, pepsin, trypsin and intestinal protease, protein macromolecules are decomposed into small peptides and even amino acids, and finally absorbed by small intestinal mucosal cells. The above is the main way of protein digestion and absorption in the traditional sense. With the deepening of scientific research, scholars have discovered more "special carrier transport channels" for small intestinal mucosal cells to directly absorb peptides, and human beings have a deeper understanding of protein absorption.
The secret of keratin is revealed
The human body has introduced the way of digestion and absorption of proteins, and it can be seen that if a protein wants to be digested by the human body, it first needs to destroy the molecular structure of the protein, and then decompose it into small peptides or amino acids.
"From top to bottom" Intermediate filaments Fibrils Primary fibrils Double-stranded helix A helix
α-keratin is the main protein that makes up hair, is one of the fibrous structural protein families, because it contains more cystine, so the content of disulfide bonds that play a cross-linking role in the protein peptide chain is particularly large, so the keratin chemical properties are particularly stable, and it is not easy to be dissolved and digested in the human environment.
This is the reason why hair should not be eaten, because it is difficult to destroy and break down keratin in normal environments.
Cats can't digest the hair licked into the stomach, and the cat shoveler knows that cats need to regularly consume cat grass or hair cream to help expel the accumulated hair in their bodies. Although it is called hair cream, it does not have the effect of hair cream, and the main ingredient of most hair cream is oil. Some cats will vomit and spit out hair balls after eating hair cream, mostly because the stomach is stimulated by oil.
It is worth mentioning that although the hair of all vertebrates is composed of α-keratin, some scholars have compared the hair of any different animal with the hair of human keratin and found that there is still a big difference between the two components, which is reflected in the content of high sulfurin.
Although hair cannot be eaten, animal feathers have been continuously studied and explored by scientists, and a variety of treatment methods have been developed, after high temperature, high pressure, acid, alkali or enzyme treatment, keratin can be broken down into short peptides or free amino acids for livestock and poultry to eat. Feathers have now become a recognized potential source of high-quality protein with high nutritional value and stable quality used in the feed and food industry, and also shine in many fields such as environmental protection, fertilizer, and pharmaceutical.