2. Vitamin C

The therapeutic benefits of vitamin C have long been known.

During his expedition to the "New World", the 16th-century French explorer Jacques Cartier was amazed at sassafras' ability to cure his men of scurvy six days after drinking tea prepared for them by the native Americans.

In the 18th century, an English sergeant in charge of feeding sailors discovered that scurvy could be warded off with a daily ration of oranges and lemons. From then on, all ships carried a cargo of concentrated lemon or citrus juice syrup, which explains the common use of the name limeys in English.

It was Dr. James Lind who discovered the curative role of lemons and oranges and recommended their use in his treatise on scurvy in 1753. But it was not until 1907 that vitamin C...