Vitamin E Shows Promise In Lowering Respiratory Infection Frequency – Study

A significantly lower incidence of the common cold was observed among elderly participants taking vitamin E, although more research is necessary to confirm the results, study researchers report in the Aug. 18 Journal of the American Medical Association.

Overall findings demonstrate that vitamin E use does not have a statistically significant effect on the number of respiratory tract infections in an elderly population and does not significantly affect duration of the infections.

However, the study points to a potentially beneficial effect for the vitamin on the number of people suffering from respiratory infections, most notably the common cold. The number of study participants taking vitamin E who experienced one or more respiratory tract infections totaled 60%, compared to 68% in the placebo group, Simin Meydani, PhD, Tufts University, et al., conclude.

The one-year study followed 617 individuals aged 65 years or older and living in long-term care facilities. Subjects were randomized to two groups: 311 patients took a 200 IU capsule of vitamin E per day, and 306 participants received a placebo pill that contained 4 IU of vitamin E.

Participants in both groups also were given a multivitamin containing 50% of the recommended daily allowance of "essential micronutrients." The number of participants who completed the study dropped to 231 in the vitamin E group and 220 in the placebo group.

Among participants who completed the study, a slight difference in the number of upper respiratory tract infections was identified, the authors report. URIs in the vitamin E group totaled 189, compared to 215 in the placebo group.

The effect of the vitamin was most pronounced on incidence of the common cold. A subgroup analysis showed that participants in the vitamin E group had a 20% lower risk of acquiring a cold compared to those in the placebo arm. The number of common colds observed in subjects who completed the study was 155 in the vitamin E group and 186 in the placebo group.

Meydani et al. note that the common cold generally is less severe than influenza. However, they point out that its "higher incidence and its recognized morbidity in the elderly make it an important public health problem in this age group. This is particularly relevant because no clinically useful vaccine or antiviral therapy is available to combat colds."

Vitamin E's observed protective effect on upper respiratory infections, particularly the common cold, "merits further investigation," the researchers assert, stating that future studies should "incorporate microbiologic methods to allow for assessment of the impact of vitamin E on specific types of respiratory pathogens."

Primary study outcomes were incidence of and number of days with respiratory tract infections, the number of people contracting respiratory infections, as well as the number of new antibiotic prescriptions for respiratory tract infections.

Over the course of the year, information relating to infection - such as temperature, respiratory and heart rates - was collected by nurses. Physicians, who were blinded to the treatment groups, evaluated the data to determine the existence, type and duration of infection. Blood samples to measure vitamin E levels were collected at three, six and nine months.

Respiratory tract infections that were identified by physicians were classified as either common cold, influenza-like illness, pharyngitis, otitis media, sinusitis, acute bronchitis or pneumonia.

Findings were not strong for lower respiratory tract infections such as acute bronchitis and pneumonia. Study authors identified no significant difference in incidence, proportion or duration of lower respiratory tract infections among the vitamin E and placebo groups.

The Council for Responsible Nutrition commented that the study "further illuminates the importance of vitamin E supplementation for the elderly" by showing "an actual impact on disease incidence." The findings differ from previous studies, which have shown that vitamin E use "improves measures of immune response."

Both CRN and the researchers note that participants' use of a multivitamin in both the treatment and placebo groups may be considered a limitation of the study. Inclusion of a multivitamin "might have lessened the impact of vitamin E on respiratory tract infection by improving the micronutrient status of the placebo group," Meydani et al. concede.