Today, the story of lemons, limes, paprika, vitamin C and sailors in the 17th and
18th centuries who spent a long time on the ocean and problems that they
encountered. All right, let's start with the lemon. You know the old song? Lemon
tree: The flower is very nice but the fruit of that tree is impossible to eat.
Well not impossible, but but not great. Malic acid and citric acid and lemon:
pretty tart. However, believe it or not, there are bloggers out there who tell us
that lemon juice is the cure-all for almost everything from diseases of the
liver to heart disease. Well there's an interesting historical
connection, realistic one with lemons and that takes us back to sailors. One of the
scourge of long ocean voyages was a disease called scurvy. Scurvy manifests
as as bleeding gums and eventually goes on to attack the heart and you can die
from this. Nobody knew what was causing this disease but it was very
very common on long ocean voyages. And then a Scottish physician came along by
the name of James Lind who thought that there might be a dietary connection and
he carried out what we can look at as the first randomized clinical trial in
history. Aboard a ship, he divided sailors into groups. Some of them he gave
sulfuric acid because he thought that that might be protective against scurvy.
Others got different foods and some got lemons and oranges. It turns out that
the sailors who got lemons and oranges were the ones who were eventually spared
of scurvy. Of course Lind didn't know what the active ingredient in there was.
That came much, much later. Today we know what it is. It is vitamin C. And vitamin C was
finally isolated in 1932 by the Hungarian scientist Albert Szent-Györgyi.
And he did it from paprika because paprika has a very high concentration of vitamin
C. Anyway, Lind thought that perhaps the reason that
lemons and oranges were protective against scurvy was because they were
acidic and it turned out that there were other fruits that were acidic that were
much more readily available to the British than lemons: limes. Well it turned
out that lime did not work quite as well as the lemons in preventing scurvy
because amazingly that has only about half the vitamin C content that lemons
had. So they switched back to lemons but in the meantime British sailors started
to be called limeys because they were eating lime. Finally in the
1930s, as I said, vitamin C was isolated from paprika and it is now available in
pill form. Today scurvy is really non-existent in the
Western world because we all have enough vitamin C in the diet but there are
other allegations about vitamin C — what it can and cannot do. For example it's
supposed to prevent a common cold. The fact is that numerous studies have shown
that just doesn't happen except in some very rare situations
where soldiers are exposed to very cold temperatures or marathon runners who are
highly stressed when they take vitamin C, anywhere from two hundred to a thousand
milligrams a day, they have somewhat fewer colds. But the evidence is not
there for taking vitamin C randomly in order to prevent the cold and certainly
the evidence is not there for lemons having any kind of medicinal value in
terms of preventing heart disease or any other medical condition. But I can tell
you that if you just take the lemon and you scrape the peel and you put it into
a salad it will add a lot of zest to the salad although I don't think lemons will
add much zest to your health.