The link between low vitamin D and dementia has again been confirmed with the publication of a robust six-year long study4 conducted by an international team of researchers. As reported by Science Daily:5<\/p>\n
\u201c[S]tudy participants who were severely vitamin D deficient were more than twice as likely to develop dementia and Alzheimer’s disease…<\/p>\n
[A]dults in the study who were moderately deficient in vitamin D had a 53 percent increased risk of developing dementia of any kind, and the risk increased to 125 percent in those who were severely deficient.<\/p>\n
Similar results were recorded for Alzheimer’s disease, with the moderately deficient group 69 percent more likely to develop this type of dementia, jumping to a 122 percent increased risk for those severely deficient.\u201d<\/p>\n
The authors concluded that: \u201cOur results confirm that vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease. This adds to the ongoing debate about the role of vitamin D in nonskeletal conditions.\u201d<\/p>\n
The findings also suggest there\u2019s a threshold level of circulating vitamin D, below which your risk for dementia increases. This threshold was found to be right around 50 nmol\/L, or 20 ng\/ml. Higher levels were associated with good brain health.<\/p>\n
Based on previous research, I believe 20 ng\/ml is still too low, and potentially dangerously so… When it comes to vitamin D, you really want to be in the optimal or clinically relevant range, and as the years have gone by, researchers have progressively moved that target range upward.<\/p>\n
At present, based on the evaluation of healthy populations that get plenty of natural sun exposure, the optimal range for general health appears to be somewhere between 50 and 70 ng\/ml, or 125-175 nmol\/L\u2014a far cry from the threshold suggested in this study.<\/p>\n