It is well known that aging is often associated with a poor immune response and a vulnerability to respiratory tract infections. It is also well recognised that nutritional status plays an important role in immune impairment, especially in the elderly. Vitamin and nutrient supplementation is thus often encouraged in the elderly under the assumption that it can only boost health, including their immune response. However, supplementing the diet with vitamin E may actually have an adverse effect on the severity of respiratory tract infections in the elderly, according to a recent Dutch study.
The investigators randomized 652 well-nourished, noninstitutionalized individuals from the Netherlands, 60 years or older, to physiological doses of either multivitamin-minerals, 200mg of vitamin E, both or placebo. The incidence and severity of self-reported acute respiratory tract infections were assessed by telephone with a nurse, home visits and microbiological and serological testing at 15 months.
Those participants taking the multivitamin-mineral supplements reported no increased rate or severity of infection. The vitamin E-users also did not report a greater incidence of infections, but they did suffer from greater severity compared to those who were not taking vitamin E. Among those randomized to vitamin E, illness duration was extended by five days and the number of symptoms experienced was six compared to four in non-users. Furthermore, 36.7% suffered from fever and 52.3% had their daily activities restricted, compared to only 25.2% and 41.1% of participants who did not take vitamin E respectively.
The study group concluded that neither daily multivitamin-mineral supplementation at physiological doses nor 200mg of vitamin E showed favourable effects on incidence and severity of acute respiratory tract infections in this group of elderly. Rather, they observed several adverse effects of vitamin E on illness severity. They suggested that further investigation of the effect of multivitamins and minerals in older persons with suboptimal plasma concentration of vitamins would be valuable. In the meantime, perhaps elderly people who are already well nourished should take caution when supplementing their diets with vitamin E.
- Graat JM, Schouten EG, Kok FJ. Effect of daily vitamin E and multivitamin- mineral supplementation on acute respiratory tract infections in elderly persons. JAMA 2002;288:715-21.
and Ginkgo for Memory Enhancement
There have been many claims that the herb ginkgo, available as an over-the-counter dietary supplement, can improve memory, attention and other mental functions in as little as four weeks. Although the herb is marketed towards both those with and without significant cognitive impairments, these claims have thus far only been supported by studies of cognitively impaired clinical populations, such as patients with Alzheimer disease. A recent randomized, controlled, double-blind study now challenges earlier notions that ginkgo facilitates performance on learning, memory, attention and concentration in healthy elderly adults.
To evaluate ginkgo's potential as a memory enhancer, 230 healthy volunteers aged 60 to 82 years were randomly assigned to receive either 40mg of ginkgo or placebo three times daily with meals for six weeks. One day before randomization, and six weeks later, participants underwent neuropsychological evaluation, including tests of memory, learning, attention and concentration, and expressive language. Volunteers also provided a self-assessment of their own memory, and each of them had a close companion evaluate their overall change in memory.
After six weeks, data showed that ginkgo did not enhance performance on standard neuropsychological tests of learning, memory, naming and verbal fluency, or attention and concentration. Moreover, there were no differences between the gingko group and those taking placebo on the subjective self-reports of memory function or on the global ratings made by their companions. Both groups showed improved performance at six weeks, most likely because they became more familiar with the evaluations the second time around.
Marketers of gingko for the enhancement of memory promise positive results in four weeks. Although it is possible that the memory-boosting powers of ginkgo take longer than the six-week period used in this study, it can be concluded that healthy, elderly adults will not benefit from this supplement if they take it according to the manufacturer's suggestions.
- Solomon PR, Adams F, Silver A, et al. Ginkgo for memory enhancement: A randomized controlled trial. JAMA 2002;288:835-40.