But overall, the researchers "found no effect of vitamin E supplementation on the incidence or duration of respiratory tract infections."
The study of 617 seniors living in 33 nursing homes in the Boston area was conducted between April 1998 and August 2001. Participants were at least 65 years old; 451 completed the study.
Respiratory infections are common in the elderly because of their advanced age and poorer immune response. Vitamin E is an antioxidant and has been shown to enhance the immune system response.
In the study, participants took a daily capsule containing half the U.S. daily recommendations of essential vitamins and minerals. Part of the group also took a vitamin E supplement (200 IU), and the rest took a placebo.
Researchers led by Simin Nikbin Meydani, DVM, PhD, of Tufts University, analyzed how many people in both groups got respiratory infections and how long the infections lasted. Both colds (upper respiratory) and pneumonias (lower respiratory) infections were followed.
Supplementation with 200 IU per day of vitamin E did not have a significant effect on decreasing pneumonias in elderly nursing home residents, write the researchers.
"However, we observed a protective effect of vitamin E supplementation on upper respiratory tract infections, particularly the common cold, that merits further investigation."
"Participants in the vitamin E group who completed the study had significantly fewer common colds and a 20% lower risk of acquiring a cold than those in the placebo group," write the researchers.
"Common colds are frequent and associated with morbidity in this age group, and if confirmed, these findings suggest important implications for the well-being of the elderly."
Most upper respiratory tract infections, especially the common cold, are caused by viruses, say the researchers, citing animal studies suggesting that "vitamin E protects against viral but not bacterial infection in aged mice."
Future studies with elderly participants should focus on whether vitamin E has an effect on respiratory tract infections caused by viruses or bacteria, write the researchers.