Shrimp skin and enoki mushrooms can improve metabolism and prevent obesity


We may have heard of the many benefits of dietary fiber supplementation, especially in helping to reduce the risk of metabolic-related diseases. A study from Duke University in the United States revealed that supplementing any type of dietary fiber can help maintain intestinal health, prevent the occurrence of colorectal cancer, and enhance the ability to resist pathogenic bacteria.

In terms of ingredients, dietary fiber is essentially a type of polysaccharide that is difficult to digest and absorb in the intestines, so their role is often ignored. It may be difficult for us to think that chitin is also a dietary fiber. Biology textbooks have told us that chitin is mainly used to make up the shells of crustaceans. How can it be dietary fiber?

In fact, the structure of chitin is very similar to that of cellulose. It is a nitrogen-containing polysaccharide with acetylglucosamine as the basic unit. If someone eats dried shrimps to supplement calcium, the calcium supplement may not be as much as chitin. In addition, chitin also appears in the cell walls of fungi, such as the indigestible Enoki mushrooms, which contain large amounts of chitin.

Although chitin is special, it has benefits for the human body just like other dietary fibers. According to a new study published in Science, animals have a special chitin digestion mechanism. Long-term consumption of chitin can help individuals improve metabolism and prevent obesity.

In addition to the involvement of the digestive system, these processes also have a key link with the immune system. In the experiment, when food rich in chitin entered the stomach of mice, the researchers observed that the stomachs of mice obviously bloated. The chitin-fed mice had larger stomach volumes than control mice fed regular chow, suggesting that the chitin caused stomach dilation.

This gastric distension process directly stimulates the innate immune response, mainly activating the expression of type 2 innate lymphocytes (ILC2) and related interleukins. The authors observed that after chitin food was consumed by mice, the number of ILC2s in the stomach increased, and the levels of interleukin-5 in the serum also increased.

In turn, the immune system stimulates the cells in the stomach to produce chitinase, which is used to break down chitin. This allows chitin, which is extremely difficult to digest, to be broken down and used by the body.

It is worth mentioning that we used to think that dietary fiber needed the help of intestinal microorganisms to break down, but research has confirmed that chitin is a special case. Germ-free mice can still elicit a natural immune response and then produce chitinase after eating chitin. Even in wild-type mice, long-term chitin consumption can affect the composition of the gut microbiome, with an increase in Bacteroidetes and a decrease in Firmicutes in their feces.

The researchers also observed that the special digestive mechanism of chitin may be the secret to helping maintain a healthy weight, especially if only the part that stimulates the innate immune response is retained, the effect will be even greater. In tests, mice that consumed chitin while eating a high-fat diet could significantly slow down their weight gain.

If the mice were engineered not to produce chitinase, weight gain would be further reduced. This is because after mice continue to consume chitin, they will adapt to produce more chitinase, helping them obtain energy from chitin.

The authors next plan to explore whether supplementing chitin in human diets can also help the body control obesity. The study authors note that there are several ways to inhibit chitinase production, which may provide the greatest metabolic benefits if paired with a chitinous diet.