Scurvy and Common Cold

Does the title of this article sound odd to you? "Common cold" is a familiar disease that people in Hong Kong often contract. On the other hand, "scurvy" should be extremely rare among our relatives and friends. Surprisingly, it makes sense to discuss these two seemingly unrelated diseases together.

Figure 1: Maritime voyages.

In the 21st century, cruise travel is a leisurely activity of choice for the middle-class, especially for those who have entered their "golden years". Today, ocean liners sail on the sea like behemoths, with displacement tonnages often over 100,000 tonnes. Passengers on board seldom feel the rough waves below them. Cruise ships are well equipped, with plenty of restaurants offering a huge variety of freshly prepared food. The elderly can thus travel around the world stress-free regardless of physical fitness, enjoy a smooth journey with family and friends, and get immersed in the rich culture and natural beauty of various destinations along the way.
Five hundred years ago, sailing was not as pleasant an experience (Figure 1). In the Age of Exploration, sea explorers from maritime countries including Portugal, Spain and England, mostly with support from European royalties, took wooden fleets into the vast seas one after another, in order to find new business and trade opportunities. Back then, the wooden ships were of limited tonnage, and the technology of freezing food had not yet been developed. Food stored on the ship was not suitable for long-term voyages. The sanitary and living conditions for seafarers were very difficult. Nevertheless, driven by both economic and political interests, successive waves of explorers were willing to take the risks of ocean voyages. They went round the southern tip of Africa, crossed the Indian Ocean, and headed towards the unknown new world through the vast Pacific Ocean. At that time, for reasons yet to be known, sailors often suffered from scurvy. For hundreds of years, this disease plagued sailors on long voyages like a nightmare. The clinical symptoms of scurvy mainly include obvious subcutaneous and gum bleeding tendencies, accompanied by swelling and pain in joints or legs, irritation and fatigue. As the disease progresses, if not treated in time, scurvy may cause very serious complications and even be fatal. During the nearly three hundred years of the Age of Exploration (1500-1800 AD) when the cause of the disease was unclear, it is estimated that more than two million sailors lost their lives because of scurvy. According to records on scurvy,1

"In 1499, Vasco da Gama (Portuguese explorer, c. 1460-1524) lost 116 of his crew of 170; In 1520, Magellan (Portuguese explorer who was appointed by the Spanish King to command a five-ship expedition, 1480-1521) lost 208 out of 230; ... all mainly to scurvy."

The mystery of this disease was eventually completely solved thanks to the Scottish Royal Navy surgeon, James Lind (1716-1794). While lemons and citrus fruits had been suggested in navigators’ records to be effective in treating scurvy, there was a lack of systematic clinical research data. In 1747, on board HMS Salisbury, Lind conducted rigorous medical research.2 He divided 12 sailors into six pairs, and to every pair he applied one of the following six methods, which had been proposed by predecessors as scurvy remedies:

By trialling these six "prescriptions" on the twelve sailors, Lind found that eating citrus fruits had obvious medicinal benefits after a week. Six years later, based on this study Lind wrote a medical commentary, in which he proposed citrus fruits as a treatment for scurvy. Since then, sailors have been able to avoid this fatal disease. The BBC's short commentary describes in more detail the causes, symptoms and pathology of scurvy.2 The cause of scurvy is actually the lack of vitamin C in the patient's body. While many animals can produce vitamin C on their own, humans, monkeys and guinea pigs do not have this ability and must obtain it through food. Human beings cannot produce collagen if they lack vitamin C. If vitamin C-containing food is not consumed at all for a month, the following symptoms can arise: obvious subcutaneous and gum bleeding tendency, as well as swelling and pain in joints or legs, skin wounds that are difficult to heal, irritability, fatigue, and fatal risks to the normal cardiac functioning.

Figure 2: Chemical structure of vitamin C.

Vitamin C is water-soluble (Figure 2). In addition to its role as an important coenzyme in the production of collagen, it also has a strong antioxidant effect, which is extremely helpful for maintaining healthy skin, bones and blood vessels. The human body cannot produce vitamin C and must rely on food sources. Nevertheless, the daily intake required by adults is only 90 mg. Citrus fruits are the main source of vitamin C. Tricolour bell peppers even possess higher vitamin C content (Table 1).3

Table 1: Amount of vitamin C per 100 g of tricolour bell peppers (uncooked) and citrus fruits

Green bell pepper 80.4 mg Lemon 53.0 mg
Red bell pepper 127.7 mg Orange 53.2 mg
Yellow bell pepper 183.5 mg Grapefruit 34.4 mg


In addition to direct extraction and fermentation from natural food sources, vitamin C can also be mass-produced through artificial synthesis and chemical purification, thanks to its simple chemical structure. However, natural fruits contain in addition to vitamin C many other constituents, and thus their health benefits to consumers are different from pure synthetic vitamin C. Therefore, consumers should first identify their needs and consumption purposes to purchase products that suit them best.4
With the development of modern science and medicine, vitamin C is not only the drug of choice for the radical treatment of scurvy, but may also be of use in other human diseases. The discussion on vitamin C will continue in the next article, which will focus on whether it can cure the common cold.

 

References

  1. https://en.wikipedia.org/wiki/Scurvy
  2. https://www.bbc.com/news/uk-england-37320399
  3. 《奇妙創造與人體奧秘選讀》陳永康著，基督教天人社出版，2024年1月，第37頁。
  4. https://balanstart.com.tw/news/detail/412

By Prof. Chan W. H.
Translate by Dr. Chan H. T.