Furthermore, it was observed that higher concentrations of vitamin D were associated with lower incidence of all-cause dementia and AD in the eldest.
The report concludes: “Our study supports the advice for monitoring vitamin D status in the elderly and vitamin D supplementation in those with vitamin D deficiency.”
Antioxidants for dementia
With a growing elderly population the prevalence of dementia has also risen, mirroring a significant drop in nutritional status.
Previous findings have suggested that the antioxidant properties of vitamin A, D, and E, and beta-carotene may enable for cognitive protection in the elderly; a group prone to non-communicable diseases such as dementia.
Specifically, vitamin D has been observed to reduce risk of developing dementia and in previous studies, whilst RCTs studying the additional antioxidant vitamins have provided inconsistent results.
Therefore, the present prospective cohort study sought to address these inconsistencies, and investigate the relationship between Vitamin D, A, E and beta-carotene and AD and incident all-cause dementia.
The data from 1,334 healthy participants with a mean age of 84 were analysed from the Aging, Cognition and Dementia (AgeCoDe) study, consisting of oldest-old general-practitioner patients in Germany.
The combined opinions of an interviewer and geriatrician enabled for dementia diagnoses to be reached, following adherence to DSM-IV and International Classification of Diseases (ICD-10) criteria. For vascular dementia diagnoses, the National Institute of Neurological Disorders and Stroke and Association Internationale pour la Recherché et l´Enseignement en Neurosciences (NINDS-AIREN) criteria was used. Of the studied cohort, 250 developed all-cause dementia, whilst 209 developed Alzheimer’s dementia (AD) following the seven years of follow-up.
Blood samples were collected to measure concentrations of vitamin A (retinol), D (25-hydroxycholecaliferfol) and E (alpha-tocopherol) and beta-carotene to determine their association with incident (AD) dementia.
It was observed that higher concentrations of vitamin D were associated with lower incidence of all-cause dementia and AD. Furthermore, those with a vitamin D deficiency were found to have a greater risk of all-cause dementia and AD.
Conversely, Vitamin A and E and beta-carotene were found to be unrelated to (AD) dementia within this cohort.
The evidence linking vitamin D deficiencies with increased dementia and AD incidence mirrors previous findings from longitudinal studies, strengthening the study results.
With the established functions of vitamin D involving the release of neurotransmitters and reducing inflammation, the observed ability to reduce incidence of neurological disorders can be explained by its neuroprotectant properties, with the researchers explaining “Vitamin D is involved in several brain functions such as counteracting oxidative stress.
“Oxidative stress, which is an imbalance between antioxidant capacity and ROS, occurs when intracellular Aß peptide in the brain binds to mitochondrial membranes, consequently interfering with the normal electron flow through the respiratory chain causing the levels of ROS to increase. Furthermore, the imbalance induces cellular dysfunction and degeneration in the brain”.
In addition, the vitamin D receptor has been found to be highly expressed in many areas within the brain, and thus, changes in its gene expression may also contribute to such conditions.
The lack of association paired with previous inconsistencies observed in the additional vitamins studied suggests the need for further research. Similarly, there is a need for further RCTs to prove a causal relationship between vitamin D deficiencies and cognitive conditions, ensuring for greater control over confounding factors that may have influenced the study results.
“Low Serum Vitamin D Status Is Associated with Incident Alzheimer’s Dementia in the Oldest Old”
Debora Melo van Lent, Sarah Egert, Steffen Wolfsgruber, Luca Kleineidam, Leonie Weinhold, Holger Wagner-Thelen, Birgit Stoffel-Wagner, Horst Bickel, Birgitt Wiese, Siegfried Weyerer, Michael Pentzek, Frank Jessen, Matthias Schmid, Wolfgang Maier, Martin Scherer, Steffi G. Riedel-Heller, Alfredo Ramirez and Michael Wagner