Back in the early 1900s it was patently obvious that pellagra (vitamin B3 deficiency) was a contageous disease.
You have to ask exactly how a disease caused by a vitamin deficiency could remotely have been classed as contagious, and exactly why this idea should have been so vigorously defended by the medical profession. To get the whole story you really need something like Alan Kraut's biography of Goldberger. I found it an interesting read, particularly the lengths Goldberger (and his family) went to in order to demonstrate on themselves that pellagra was not contagious, and quite how his wife put up with coming such a distant second place to his work is quite beyond me. Anyway, it turned out that the "Scourge of the South" could be cured by decent food, eventually replaceable by a teaspoonful of brewers yeast a day.
Just imagine heart disease being cured by a pint of cream a day...
How did the medical profession take this to phenomenal and meticulously tested hypothesis? If you think the AHA hated Dr Atkins, that has nothing of the violence of the reaction against Goldberger. To say they were not best pleased might be a slight understatement. They hated him. The reasons were essentially financial and political, a bit like heart disease today. Being correct does not always make for popularity.
Now let's have a look at subacute myelo-optico-neuropathy (SMON). OK, hands up if you have never heard of SMON.
The disease was pretty well limited to Japan between 1958 and 1972, so you may be excused. Identification of the cause was severely hampered by the obvious explanation that it was contagious and was caused by a gut virus. The fact that it ultimately turned out to be caused by a known neurotoxin marketed by Ciba Geigy as a drug for the treatment of diarrhoea was vigorously denied by the virus hunters, even after what had really happened became fully accepted by the Japanese government.
To get some idea of how much fun SMON was for the victims, over 1000 of them were still alive in 2004 (of the approximately 10,000 affected). These are the types of problem the survivors are still left with.
Here's a nice summary of the whole episode, it makes interesting reading. Duesberg is probably the world's leading AIDS denialist.
For those of us who were stacking straw bales in the university vacation during the blistering summer of 1976, SMON doesn't seem that long ago.
This poses the very interesting question: When did we stop making mistakes?
and the closely related question: Statins in the drinking water?
Hmmm, you could ask things about BSE and vCJD too....