studies suggest that high intake of , and carotenoids ( —are
associated with a reduced incidence of cataracts. However, this
by itself does not prove that the use of antioxidant supplements
can prevent cataracts. Only studies can do that. (For
information on why the double-blind design is so important, see
Why Does This Database Rely on Double-blind Studies? )
Unfortunately, the results of several large studies of this type
were not encouraging. In an enormous, double-blind, placebo-
controlled trail involving almost 40,000 female healthcare
professionals, use of natural at a dose of 600 mg every other
day over a 10-year period failed to have any effect on cataract
development. In another large, 8-year trial, 11,545 physicians
aged 50 years and older were randomized to four different
treatment groups: vitamin E (400 units) every other day plus
vitamin C (500 mg) daily, vitamin E every other day plus placebo
daily, vitamin C daily plus placebo, or placebo only. Neither
vitamins E or C had any significant effect