Long-term daily multivitamin supplement use decreases cataract risk in men, study finds. Long-term daily multivitamin supplement use may lower cataract risk in men, according to a study of nearly 15,000 male physicians. Half took a common daily multivitamin, as well as vitamin C, vitamin E and beta carotene supplements. The other half took a placebo. The researchers followed the participants to identify how many participants in each group developed new cases of two common eye diseases: cataract and age-related macular degeneration. Results showed a 9 percent decrease in risk for those that took the supplements.