There may be some advantage in a relative increase in protein intake by those engaged in
building exercises, but not if the basic protein intake is already plentiful (see
PROTEIN-SUPPLEMENTED FOODS ARE BETTER FOR YOU).
The use of vitamin and mineral supplements to improve athletic performance has been
advocated. There is no clear evidence of benefit. The difficulty, however, is that elite athletes
seeking very small increments in performance. It is almost impossible to obtain scientifically
proof that performance with a supplement was significantly different to that with a placebo
(dummy preparation) for a small number of performances. The practice may have to be
if athletes and their coaches believe it to be beneficial, and it does no detectable harm.
One should be wary of manufacturers who arrange for athletes to be taking their products
time of a success. Later advertising campaigns may give the impression that a chance
is actually the reason for their success (a cause and effect relationship).