Vitamin supplements are widely used in elderly patients, and studies show that multi-vitamins, multivitamins plus minerals, and vitamin E are the most commonly used supplements. Studies have shown that such supplements improve some cellular immune parameters, but evidence about the actual clinical effects is inconclusive. Graat and colleagues conducted a randomized controlled trial to determine the effect of various supplements on the incidence and severity of acute respiratory infections in elderly persons.

Individuals were included if they were at least 60 years of age, had no history of cancer, liver disease, or fat malabsorption, and had not used supplements, immunosuppressive treatments, or certain anticoagulants in the previous two months. Participants were followed for up to 15 months and were randomized to receive a placebo, vitamin E, a multivitamin with minerals, or a multivitamin with minerals and vitamin E. The main outcomes measured were acute respiratory-infection incidence and severity. Participants reported symptoms consistent with acute respiratory infection to the study nurse, who determined whether the participant met criteria for acute respiratory infection. A random subsample of participants had microbiologic and serologic tests for confirmation.

There were 547 persons included in the analysis. Almost all (98 percent) of the participants were noninstitutionalized. The follow-up period for 92 percent of the participants included winter months. In the group that took the multivitamin with minerals, 71 percent had at least one acute respiratory infection. In the group that received vitamin E, 68 percent had an infection. In the group that received the multivitamin with minerals and vitamin E, 66 percent had an infection. In the placebo group, 67 percent had an infection. Patients who were given vitamin E and had a respiratory infection had longer illnesses and statistically and significantly more symptoms than other patients.

The authors conclude that neither multivitamins with minerals nor vitamin E is associated with a lower incidence of acute respiratory-tract infection in elderly patients. Vitamin E was associated with longer duration and increases in symptoms. It may be that elderly persons should be cautious about supplementing their diet with vitamin E, at least as a means of improving immune function.