Monday, 19 August 2013

Vitamin Woowah

While half the population is horsing through the brightly coloured product range of Nabisco and Nestle's food chemists, the other half are horsing through a veritable pharmacopoeia of multi-vits, as if this avenue is "healthier".

A lot of what we believe to be true about the benefits (near universal, it seems) of vitamin C, (and by extension other vits) is due to relentless decades-long pushing by Professor Linus Pauling who won two Nobel prizes before he died on 19th August (today) 1994.  Pauling made really fundamental contributions to our understanding of biochemistry, particularly the structure of proteins (the alpha-helix was his idea).  He also discovered that a single genetic mutation in hemoglobin had physical, physiological and medical (sickle-cell anemia) consequences and so midwifed the birth of  molecular biology.  His classic mega-cited multi-edition book The Nature of the Chemical Bond was required reading for two generations of bio-scientists.  His second Nobel was for Peace because after WWII he became such an ardent peacenik that he had his passport seized for a while by the US State Department to prevent him talking to the Reds that were, in those McCarthy Era days, under every unamerican bed.

Later he became shining-eyed-sure that Vitamin C was not only a cure for the common cold and 'flu, but also for cancer.  To do this he had to abandon a life-time of scientific training to follow where the data led.  Unaccountably he preferred to lead from the front in a personal jihad against disease while vigorously waving a vitamin C flag and letting the data for its efficacy fall where it may.  Up until last month, I had been a desultory popper of vitamin C tablets on the premiss that the habit was at worst harmless even if the good it might do was marginal.  I used to tell people that the evidence showed that, if taken before the fact, sufficiently large doses of vitamin C would, on average, slightly reduce, by 3/4 of a day IIRC,  the length of your suffering with a cold.  Your nose would stream as much, your eyes would be as red and you'd feel as crappy as usual but not for so long.  I think now that if I had done a proper study of all the data from the very many carefully controlled investigations, even this marginal benefit would be suspect not to say wrong.

In July, a long and quite angry article in Atlantic Monthly - whence I get a good proportion of my long-form reading over the interweb - by Paul Offit explodes this cosy primum non nocere view.  Several carefully controlled studies have shown that people who take multivits are more likely to die from various forms of cancer - including prostate, lung and GI tract. Ooops! One of the problems with reporting science for ordinary folk is a strong tendency to talk up the new and exciting and fail to report the painstaking repeat studies that undermine or contradict the original finding especially if the original is written by a Nobelist. Even within science we have real problems with replication and reporting mundane negative results. 

Next month I'm going to start teaching Human Physiology again to The Institute's 1st Year students.  The pervasive theme in any such course has to be the concept of homeostasis - the observation that all our bodily functions are arranged about a set point and that complex, subtle and redundant mechanisms are in place to maintain them there: core body temperature at 37oC is the most obvious example.  Too much selenium or vitamin C or E is seemingly as bad a thing for the roundabouts as too little is for the swings, perhaps because they overwhelm the normal homeostatic mechanisms.

If, without an exhaustive study of the science behind the claims, you choose to believe that your diet in Ireland or Россия or the US is in some sense deficient and you therefore buy and consume vitamin supplements, you are a fool with too much money. I'll put it stronger than that: for every multivit you pop a small black child, who really is on the edge of nutritional insufficiency, dies [The math: $10 for 50 MV pills is 20c a day, while 1 billion people live on $1 a day or less].  Sorry folks, but science is hard. Tracking down and reconciling a couple of dozen contradictory, slightly different studies is a lot of work, so you may think that a long article by the highly qualified Professor Paul Offit will sufficiently inform you. It is very interesting and I urge you to take the half-hour it requires to read it.  But Offit is not above a rhetorical device or two to make his point.  After citing all the studies that showed how wrong Pauling was about the value of vitamins in dealing with prostate cancer, the final sentence of Offit's article is "In 1994, Linus Pauling died of prostate cancer." Duh! Pauling was 93 and a half when he died. From which I take, Professor, that those multivits worked treat for Linus Pauling keeping him going for more than two decades over his allotted three-score-and-ten.  I think I'll start a course now and forget about the black babies.

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