Hypothesis: Cartilage protection is connected to preventing development of pneumonia, especially that caused by COVID-19

I think there is an overlooked cartilage connection to the development of fatal pneumonia. Below I will point to how this hypothesis is supported by the current COVID-19 epidemic.

First, why a cartilage connection? Because in the 1918 influenza epidemic, a doctor's record indicates that those recovering influenza patients who sat up, ate solid food, and brought on coughing by being in smoke-filled rooms, quickly relapsed and died of pneumonia while patients who stuck to liquid diets and lay flat survived. (See https://www.archives.gov/exhibits/influenza-epidemic/records/visiting-doctor-letter.pdf) Hyaline cartilage is found in the trachea, larynx, and bronchi.

A longitudinal study looking at glucosamine--a shellfish component that is taken to protect against cartilage damage--found that glucosamine supplementation was associated with reduction of mortality from all causes and was associated with a very marked reduction in mortality from respiratory illnesses. (See https://link.springer.com/article/10.1007/s10654-012-9714-6)

If such a cartilage connection exists, why has it not been noticed by medical researchers previously? Conventional wisdom until recently has been that cartilage is "immune-privileged," i.e., that it is not attacked by the immune system even when cartilage cells are infected with a virus. Recent arthritis research indicates that the immune system does sometimes attack and cause destruction of cartilage cells. (E.g., https://www.nature.com/articles/s41598-018-36500-2 and https://www.nature.com/articles/srep16674) This points to an overlooked research avenue for pneumonia researchers.

Why should COVID-19 researchers spend precious time looking into this possibility when there are so many research areas they could be focusing on? Because environmental clues are pointing us to glucosamine and have since Chinese New Year travelers first left Wuhan carrying COVID-19 with them. 

COVID-19 is a highly contagious virus. China is highly connected via established tourism, trade, and other travel patterns to the countries of southeast Asia. Thailand, the Philippines, Vietnam, and Cambodia all had COVID-19 contacts and cases early in this pandemic. All are countries with densely populated areas and very poor infrastructure to support sanitation measures and any widespread ventilator needs. Why do they still have so few deaths compared to European countries and the USA? Vietnam and Cambodia still have no fatalities at all. Consider that for a moment: Cambodia and Vietnam combined have had nearly as many cases but far fewer deaths (i.e., zero) than Hawaii.

One reason could have been that those four southeast Asian countries are warmer countries. But tiny Singapore is warm. Spain and Italy are not snowbound in March. Louisiana, one of the hardest-hit US states, is a warm place. And, of course, Hawaii is very warm.

These four southeast Asian countries share a common dietary element that is mostly unused outside of that region: fermented shrimp paste. Shrimp paste is a very good source of readily bioavailable glucosamine. Shrimp paste is integral to meals in both Cambodia and Vietnam. It is commonly, though not universally, used in Thai cooking. Shrimp paste is a frequently used condiment in the Philippines, especially as a companion to green mango slices. A survey of the COVID-19 statistics supports a conclusion that consumption of fermented shrimp paste in the national diet is inversely related to COVID-19 case and mortality burdens.

Glucosamine is a widely used supplement--so it has a track record for safety already--that can be easily administered. There is vegetarian glucosamine available for those with shellfish allergies. In order to maximize its absorption by the surfaces of the upper respiratory tract, glucosamine can be included in warm broths and/or sucked on in the mouth to permit it to be aerosolized to some degree. Nebulizer administration appears to be a possible option for administration of glucosamine directly to the bronchi.

It’s worth investigating this hypothesis. The cost to test glucosamine's helpfulness in controlling COVID-19 symptoms is as minimal as you can get for a medication, and the potential benefit is huge in light of Vietnam and Cambodia’s continuing lack of fatalities from COVID-19. 

Disclaimer: I have no profit motive in posting this. I am an independent researcher who has lived on four continents and researches how regional diet differences could be connected to the epidemiology of various health issues.