Despite an improvement in recall memory, the supplements were not associated with any other positive effects on mental functioning, researchers from Monash University and Swinburne University of Technology report in the Journal of Alzheimer's Disease.
The meta-analysis included data from 10 randomized, placebo-controlled trials involving 3,200 participants and multivitamin interventions lasting for at least one month.
The same researchers from Swinburne University recently published data from their own clinical trials that supported a role for a daily multivitamin and mineral supplement in enhancing memory in older women (Psychopharmacology, Vol. 220, pp. 351-365), while a similar supplement in men was associated with increased alertness and feelings of ‘general day-to-day well-being’ (Human Psychopharmacology: Clinical and Experimental, Vol. 26, pp. 560–567).
According to a National Institutes of Health (NIH) State-of-the-Science Panel, half of the American population routinely use dietary supplements, with their annual spend estimated at over $20 billion.
Recent results of the National Health and Nutrition Examination Survey showed that 35 per cent of the US adult population regularly consumes one or more types of multivitamin product (Am. J. Epidemiol., 2004, Vol. 160, Pages 339-349).
“Although adequate vitamin and nutrient concentrations are necessary for optimal health and cognitive functioning, there is no scientific consensus as to whether multivitamin use prevents cognitive decline or improves mental functioning,” explained the Australia-based researchers, led by Natalie Grima from Monash.
Grima and her co-workers performed a systematic review and meta-analysis of multivitamin supplementation on any valid cognitive outcomes in randomized, placebo-controlled trials.
While an improvement in immediate free recall memory was observed, the researchers found no effects on delayed free recall memory or verbal fluency.
The potential effects of multivitamin supplementation on markers of Alzheimer’s Disease could not be determined from the data, they added, as this was “under researched”.
Multivitamins & ‘biological age’
In addition to supporting daily intakes of key micronutrients, a daily multivitamin has been linked to a number of potential health benefits.
Intriguingly, scientists from the National Institute of Environmental Health Sciences have reported that the cells of multivitamin users may have a younger biological age than cells from non-users.
By focusing on the length of telomeres, DNA sequences at the end of chromosomes that shorten as cells replicate and age, the researchers reported that telomeres of daily multivitamin users may be on average 5.1 per cent longer than in non-users.
This study’s findings were published in the American Journal of Clinical Nutrition (June 2009, Vol. 89, pp. 1857-1863).
Source: Journal of Alzheimer's Disease
Published online ahead of print, doi: 10.3233/JAD-2011-111751
“The Effects of Multivitamins on Cognitive Performance: A Systematic Review and Meta-Analysis”
Authors: N.A. Grima, M.P. Pase, H. Macpherson, A. Pipingas