In an article scheduled for publication in the Journal of Geriatric Psychology and Neurology, researchers from the Peninsula Medical School, the University of Cambridge, and the University of Michigan report an association between low levels of vitamin D and an increased risk of cognitive impairment in older men and women. Cognitive impairment has been shown to enhance the risk of developing dementia, a major cause of disability among older individuals.
The current study included 708 men and 1,058 women aged 65 and older who participated in the Health Survey for England 2000. Neurocognitive testing revealed cognitive impairment in 212 subjects. The risk of impairment was found to increase with declining levels of serum 25-hydroxyvitamin D. Participants whose vitamin D levels were among the lowest 25 percent of participants at 8-30 nanomoles per liter experienced an adjusted risk of cognitive impairment that was 2.28 times greater than that of men and women whose vitamin D levels were in the top quarter at 66 to 170 nanomoles per liter.
"We provide new evidence to suggest that serum 25-hydroxyvitamin D is related to cognitive impairment in the elderly population and a potential diagnostic aid for screening or differential diagnosis," the authors write. "This is important because serum 25-hydroxyvitamin D may play an important role in the expression of neurotrophic factors, the stimulation of adult neurogenesis, calcium homeostasis, and detoxification. Furthermore, the association between serum 25-hydroxyvitamin D levels and cognitive impairment underlines the importance of micronutrients in the elderly."
"This is the first large-scale study to identify a relationship between vitamin D and cognitive impairment in later life," noted study coauthor Iain A. Lang, PhD, of Peninsula Medical School in Exeter, England. "Dementia is a growing problem for health services everywhere, and people who have cognitive impairment are at higher risk of going on to develop dementia. That means identifying ways in which we can reduce levels of dementia is a key challenge for health services."
"For those of us who live in countries where there are dark winters without much sunlight, like the UK, getting enough Vitamin D can be a real problem -- particularly for older people, who absorb less vitamin D from sunlight.," Dr Lang observed. "One way to address this might be to provide older adults with vitamin D supplements. This has been proposed in the past as a way of improving bone health in older people, but our results suggest it might also have other benefits. We need to investigate whether vitamin D supplementation is a cost-effective and low-risk way of reducing older people's risks of developing cognitive impairment and dementia."
Related Health Concern: Mild cognitive impairment
Taking steps to improve one's overall health is highly recommended to help prevent or minimize age-associated mental impairment. For example, exercising regularly, not smoking, and monitoring blood cholesterol levels can reduce the risk of stroke and heart disease and keep arteries open, supplying the brain with essential oxygen and nutrients. Abstaining from alcohol can also help preserve mental function.
Since most people tend to eat less as they age, the consumption of low-fat, nutrient-rich food is recommended to help prevent nutrient deficiencies. Eating large quantities of foods rich in antioxidants, such as blueberries, may provide protection from age-related mental decline.
A typical American diet does not provide enough essential vitamins. Worse yet, older people are at greater risk for vitamin deficiency because they tend to eat less, although their requirements for certain vitamins, such as B6, actually rise with age. Older people may also have problems with efficient absorption of nutrients from food. Even healthy older people often exhibit deficiencies in vitamin B6, vitamin B12, and folate.
Vitamins are involved in biochemical processes throughout the body and appear to be involved in protecting and enhancing cognitive function. In particular, the B vitamins play an integral role in the functioning of the nervous system and help the brain synthesize chemicals that affect mood. A balanced complex of the B vitamins is essential for energy and for balancing hormone levels. An article in the Journal of Psychopharmacology described a study of 76 older men who were given vitamin B6 or placebo and then tested on memory function. The authors concluded that vitamin B6 improved storage and information retrieval (Deijen JB et al 1992). Another study reviewed vitamin B12 deficiency in relation to memory impairment and neuropathy in older people and concluded that both memory impairment and neuropathy can be successfully managed with vitamin B12 injections or supplementation (Carmel R 1996). One study determined that low levels of folate (a B vitamin) are associated with cognitive deficits and that patients treated with folic acid for 60 days showed a significant improvement in both memory and attention efficiency (Fioravanti MFE 1997).