The "discovery" of vitamin A

It is easy to think that one person discovered a vitamin on a Thursday just before lunch. It makes history so much easier to re-tell. In the case of vitamin A, the process of discovery spanned 130 years, starting in 1816 when a French physiologist Francois Magendie fed dogs a poor diet and found they died in a similar fashion as malnourished infants, and ending with its manufacture in 1946.

Milk gave the clue

Through a series of experiments in the late 19^th century it was clear that milk contained something that was important to life. Giving animals the separate components of milk – lactose, protein, fat and salts – could not sustain life, yet whole milk could.

This was the time when the dogma dictated that life needed only protein, fats and carbohydrates, and some minerals like iron, so finding there was more to nutrition and life was surprising. What was this mystical component in milk?

  

Dietetic factors

Biochemist Frederick Hopkins in 1906 proposed that there were “unsuspected dietetic factors” in food that accounted for conditions such as scurvy and rickets. We now know they were caused by a lack of vitamins C and D respectively.

At this time it was also assumed that all fats were the same, yet different fats had a different ability to support life. If animals were given the fat extracted from eggs or milk, or simply as butter, they lived but if the fat came only from lard or olive oil they died. The fat-soluble substance in butter and egg yolk actually contained vitamins A, D and E, all of which were yet to be identified.

Then things began to fall into place and clever people started finding a range of vitamins. Hopkins was awarded the Nobel prize in 1929 (along with Christiaan Eijkman) for “the discovery of the vitamins”, and in his acceptance speech he acknowledged the work of those who went before.

Scientists behaving badly

Then the bunfight began. Elmer McCollum from the University of Wisconsin claimed that he had discovered vitamin A in 1913 because he had worked out it was a fat-soluble compound, despite others having determined that fact in the preceding 20 years.

McCollum would continue to claim that he was the one to find vitamin A, yet was unable to get any backers. He attacked rivals, sabotaged research, stole colleagues research notebooks, so it was no surprise that he wasn’t nominated for a Nobel Prize.

It took until 1937 before we knew the structure of vitamin A and until 1946 before it was first manufactured, completing the process of discovery.

Vitamin A not the first vitamin

You would assume that vitamin A was the first vitamin found, then isolated in a laboratory and declared to the world. Not so. That was vitamin B, now known as vitamin B1 or thiamine, first isolated in 1912 by Casimir Funk who said that thiamine was a “vital amine” and coined the term “vitamine”. Now both vitamine and thiamine have lost that last “e”. As long time readers will know, Popeye consumed spinach for its vitamin A content, not for its iron. Well, for the beta-carotene content really, but back in 1932 we didn’t know that beta-carotene became vitamin A in the body.

During the second half of the 20^th century, vitamins were given almost god-like status, with most of the claims and beliefs being disproven. We were swallowing mountains of vitamin C in the hope it stopped the common cold (it didn’t), and we hoped a multivitamin would reduce stress and perk us up (not that easy, sorry). OK, the B vitamin folate as a supplement for expectant Mums can help reduce the risk of spinal deformities in the foetus, so it wasn’t all bad news.

What does it all mean?

The science of vitamins is a very young science and there is much more to discover. Although small amounts of vitamins are needed to avoid disease, we are not clear on the amount needed to prolong life or prevent a disease. One genuine concern is that although vitamins are considered “natural” we love to take them in amounts not found in nature. Could years of taking vitamin supplements become a health problem in the future? There is some evidence that says “Yes” and other evidence that says “No problem”.

Reference:

Semba RD. On the ‘discovery’ of vitamin A. Annals of Nutrition & Metabolism 2012; 61: 192-198