Vitamins
Vitamins mean business. We cannot live without them, and vitamin pills are big business (est. USD68 billion per year worldwide). Science has confirmed they’re essential for health, but is equivocal as to whether there is a benefit to vitamin supplementation in developed countries.
We haven’t known about vitamins for all that long. The concept is as recent as 1911. The credit goes to a Polish scientist, Casimir Funk, who was intrigued by beriberi. This potentially-fatal central nervous system disorder was common in regions where the diet depended on polished rice. Husks are removed from rice to prolong shelf life because the husks are high in oils that can go rancid. Better industrialisation meant better husk removal.
Funk fed pigeons polished rice until they developed beriberi symptoms (polyneuritis). He then made two fractions, fraction A from polished rice and fraction B from the husks. The pigeons fed fraction A did not recover, while those fed fraction B did. He then isolated an amine (nitrogen-containing molecule) from fraction B that he showed was the active ingredient.
He called this a ‘ vital amine ‘ (vita = life), which he abbreviated to vitamine. He called it vitamine B1 because it was the primary ingredient extracted from fraction B. Funk then proposed the idea that dietary deficiency caused diseases such as beriberi, scurvy and rickets. He concluded that “… all the deficiency diseases can be prevented by a complete diet. A monotonous diet ought to be avoided …”. He had claim to be the father of nutrition.
The problem was that the medical community already knew what caused disease — it was germs. The concept of a disease arising from dietary deficiency was not accepted. Funk was not even allowed to use the word vitamine when he eventually managed to get his work published — it went under the title “On the chemical nature of the substance that cures polyneuritis in birds when subjected to a diet of polished rice”. He was forced to use a title so dull that it obscured the significance of his work.
As late as 1917, an editorial in the prestigious Journal of the American Medical Association ridiculed the notion of dietary-deficiency disease.
Funk never did receive the accolades and recognition he deserved for this discovery. Untold people are in good health today because of his pioneering work. He died in 1967.
We now know of 13 vitamins that are vital to life. The ‘e’ has been dropped because not all of these vitamins are amines.
Many vegetables are high in vitamins, and we should eat them. But nature is perverse and plants don’t see being eaten as desirable. Many plants high in vitamins also come equipped with anti-nutrients that stop uptake of those vitamins and limit nutrition. They also use toxins to avoid being eaten. Chemicals are a plant’s main defense.
For example, spinach is high in oxalic acid that inhibits iron uptake — which is ironic, bad pun notwithstanding, given that spinach is high in iron. Oxalic acid is also found in rhubarb, chard, parsley and chives. Iron is a trace element of course, not a vitamin, but I include it here because trace elements (iron, cobalt, chromium, copper, iodine, manganese, selenium, zinc and molybdenum) are also essential and sometimes supplemented.
Red cabbages, brussels sprouts and beets contain vitamin B1, plus an inhibitor to stop us benefiting from it; egg yolks contain an anti-nutrient that binds other B-group vitamins and restricts uptake; some grains come with magnesium, copper and zinc uptake inhibitors; soy beans inhibit B12 and D uptake; kidney beans inhibit E. That’s a partial list.
Cooking destroys most anti-nutrients, while most vitamins, apart from vitamin C (which we get from other sources such as citrus) survive cooking reasonably well. This may be an evolutionary advantage our species derived from learning to cook — cooked vegetables are more nutritious because the anti-nutrients are destroyed, and the nutrients are more available to us because cell walls are softened.
So, vitamins are vital, but do we get enough and should we supplement them? Or — do we not really need to supplement them but might it be an insurance anyway?
Presently there is scientific discussion for and against this proposal, with the case against prevailing for now. We don’t even really know what level defines ‘deficiency’, unless the deficiency is fairly extreme (in the West we are talking about sub-clinical deficiencies). It also depends on the population — vitamin and mineral fortification and supplementation has had a dramatic effect on public health in developing countries, and fortification has benefited developed societies too (for foods where processing strips away vitamins).
Also consider the need for daily supplementation. For example, the body stores about a month’s supply of vitamin C (which is why scurvy only became apparent as sea voyages lengthened) and the body keeps stores of vitamins A, D and B12that last even longer.
My guess is that the health benefits of vitamin supplementation in western societies will always be equivocal. Some things are not easily determined in health research. If there is some benefit, it is probably vanishingly small (which is why it is difficult to prove).
Meanwhile, a lot of tasty and healthy fruits and vegetables could be purchased for 68 billion dollars.
Further reading:
Moyer, MW (2014) Vitamins on trial. Nature. 510 (26 June): 462–464
Piro, A et al. (2010) Casimir Funk: His discovery of vitamins and their deficiency disorders. Annals of Nutrition and Metabolism. 57:85–88.
Kipple, KF (2000) A Movable Feast — from: The Cambridge World History of Food (KF Kiple and CO Kriemhild, editors, Cambridge University Press)
Steingarten, J (1998) The man who ate everything (Vintage books, NY)
