Cognitive decline, loss of episodic memory and other functions with older adults has been linked to insufficient or deficient levels of vitamin D.
A new study conducted by researchers at the Rutgers University, New Brunswick and the University of California Davis Alzheimer’s Disease Center showed that vitamin D deficiency or insufficient levels of vitamin D are linked to cognitive decline, increased risk of dementia or brain atrophy.
The study was conducted on 113 African American participants, 96 Hispanic and 158 white. The average age in the study group was 76 years old. Drawing on results of previously conducted studies, showing the over half of the U.S. population in the age group above 60 present vitamin D deficiency or insufficient levels, the new research studied the production of 25-OHD in the blood and the link to declining cognitive abilities.
Other studies have also shown that in between 70 and 90 percent of people diagnosed with cognitive impairment have low levels of vitamin D in the blood.
25-OHD is the form of vitamin D in the blood. Levels of 25-OHD are measured via blood tests. As such, all participants were tested periodically over a period of five years. During this time, their cognitive abilities were also kept under scrutiny.
According to guidelines, sufficient levels of 25-OHD are estimated between 20ng/mL and 50ng/mL. Below 12ng/mL is considered vitamin D deficiency, while between 12ng/mL and 20ng/mL is considered insufficient.
In the new study, 60 percent of the participants had insufficient vitamin D circulating through the blood, including 25 percent who presented vitamin D deficiency.
Among the findings of the study: participants with lower vitamin D levels, measuring approximately 16.2 ng/mL also presented dementia. Mild cognitive impairment was observed in patients with 20ng/mL.
In a five-year timeframe, executive function and episodic memory declined rapidly in participants that had low vitamin D levels. These processes were observed to happen at approximately the same rate both with participants who, at the onset of the study had a normal brain function, and with those who were observed to already have mild cognitive impairment.
Still, the researchers don’t recommend that vitamin D intake is increased artificially. There isn’t medical evidence showing that an increased intake of vitamin D could successfully prevent cognitive impairment, memory loss or dementia. Moreover, using supplements is not recommended beyond a certain daily limit.
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