Vitamin E Offers No Relief from Respiratory Infections

Source: Tufts University
October 11, 2002 (Reviewed: October 19, 2004)

It has been suggested that vitamin and mineral supplements - particularly vitamin E - can improve immune function in the elderly. However, there are not many conclusive trials confirming this benefit. Dutch researchers have investigated the effect of multivitamins, minerals, and vitamin E on acute respiratory tract infections in older individuals, and published their findings in the Journal of the American Medical Association.

The randomized, double-double blind study involved 652 non-institutionalized adults, ages 60 and older. Participants were randomly assigned to one of four daily treatments: a multivitamin with minerals, vitamin E (200 mg/dL of alpha-tocopheryl acetate), a multivitamin with minerals and vitamin E, or a placebo. The multivitamin with minerals capsule contained dosages at recommended dietary allowances (RDAs) for vitamins and 25% to 50% of RDA levels for minerals. Blood samples determined participants' baseline levels of some vitamins and carotenoids.

Monitoring acute respiratory infections

Outcomes of interest were incidence and severity of acute respiratory infection, defined as sudden onset, a pattern differing from chronic symptoms, and one or more respiratory symptoms (rhinitis, sore throat, or cough) lasting for at least 2 days. Participants recorded these in a diary, along with any accompanying signs such as fever, wheezing, headache, muscle or sinus pain, and medication use. The study nurse confirmed whether reported symptoms met the definition and a nose-throat culture identified the respiratory pathogen.

After 15 months of follow-up the researchers found that neither the incidence nor the severity of infections was significantly different between the multivitamin group and those not receiving the multivitamins. And while consuming vitamin E capsules did not alter the incidence, the severity was affected, but not in the way expected. In fact, infected individuals taking vitamin E were ill for longer, had more symptoms, more fever, and more restriction of their activity than those who did not take vitamin E.

Potential benefits of vitamin E

These findings contradict previous studies that showed a beneficial effect of vitamin E on immune response. It is thought that vitamin E may enhance lymphocyte proliferation and IL-2 production and decrease prostaglandin activity. However, because this study population was well- nourished, additional supplementation may have offered little added benefit.

Too soon to draw conclusions

Multivitamins and vitamin E are among the most common supplements used by older adults. Recommendations on the use of vitamin E may need to be modified if these results are confirmed by further research, although the vitamin may have other benefits unrelated to immune status.

Source

• Effect of daily vitamin E and multivitamin-mineral supplementation on acute respiratory tract infections in elderly persons. JM. Graat, EG. Schouten, FJ. Kok, JAMA, 2002, vol. 288, pp. 715--721

Related Links
Nutrients May Enhance Immune Function in the Elderly
Asthma May Be Over-Diagnosed in Obese Individuals
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