'Limited evidence' for vitamin B12 & neurological function in elderly: Oxford University review
The researchers said low vitamin B12 status was common in older people due to poor absorption, leading some to link such deficiencies to neurological conditions.
Yet in this latest review, researchers from the London School of Hygiene and Tropical Medicine, King's College and University of Oxford in the UK wrote: “The functional and public health significance of low vitamin B12 status in older people is currently unclear. In the clinical setting, impaired neurological function is a known marker of frank vitamin B12 deficiency. However, whether neurological impairment is associated with low vitamin B12 status at a population level is unknown.”
Looking at the data available, they found one long-term study of general population older people reported no association while four of the seven cross-sectional studies reported limited evidence of an association of vitamin B12 status with some, but not all, neurological outcomes.
Among groups with clinical evidence of low vitamin B12 status, one long-term study found an association of vitamin B12 status with some but not all, neurological outcomes and three cross-sectional analyses reported no association.
Writing in the British Journal of Nutrition, they concluded: “The heterogeneity and quality of the evidence base preclude more definitive conclusions, and further high-quality research is needed to better inform understanding of public health significance in terms of neurological function of vitamin B12 status in older people.”
Population sizes of the studies included ranged from 28–2287 participants and the average age from 65–81 years.
The researchers said 5% of UK adults aged 65–74 years and 10% of over 75s had low vitamin B12 levels of less than 150 picomole/liter (pmol/l) or metabolically significant vitamin B12 deficiency of less than 200 pmol/l.
Despite this, the most recent National Diet and Nutrition Survey of the UK showed intakes were mostly adequate, with only 1% of adults aged 65–74 years and over 75 falling below lower reference nutrient intakes. Absorption factors such as decreased gastric acidity and compromised functional and structural integrity of vitamin B12-binding proteins could contribute to poor status in older people, they said.
Author: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S0007114515002226
“Is there an association of vitamin B12 status with neurological function in older people? A systematic review”
Authors: L. M. Miles, K. Mills, R. Clarke and A. D. Dangour
