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No matter how good your diet or outdoor lifestyle, you are unlikely to get enough vitamin D into your system to achieve optimal levels. Therefore, as part of your plan to avoid dementia in later life, head straight to the supplements. There is no effective medical treatment for dementia, but vitamin D does a good job of warding it off.
Unlike drugs, vitamin D is an essential requirement for brain function. So, today I’m discussing how much you should take and in what form, who’s most at risk of deficiency, and whether you should be worried about vitamin D toxicity.
There is extensive evidence to support the case for supplementation. It all points towards the same conclusion: taking vitamin D has a positive effect on memory and mental faculties. This was highlighted in a study published just very recently (March 2023) in the journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring.
Over 12,000 dementia-free people with a mean age of 71 participated in this large-scale, ten-year study. Of the group, 37% took vitamin D supplements. The effects of the intervention were then assessed by the Canadian and British research team that carried out the study.
The results were significant: there were 40 per cent fewer dementia diagnoses in those participants who took regular supplements than those who did not. Taking vitamin D supplements was also associated with remaining dementia free for longer.
Co-author Dr Byron Creese, at the University of Exeter commented:
" The link with vitamin D in this study suggests that taking vitamin D supplements may be beneficial in preventing or delaying dementia..”
Before we get too starry-eyed in our vitamin D appreciation, let me state that this isn’t some shamanistic elixir that magics away memory problems. When you view the matter through the other end of the lens, you see that vitamin D is only doing its job. It is deficiency of this important nutrient that creates the problems that can lead to dementia.
Many earlier studies have revealed that lack of this key brain nutrient in the elderly can manifest as reduced cognitive function, especially in those aged 65 and over. A 2014 US study of more than 1,600 elderly adults who were monitored for over five and a half years concluded:
“Our results confirm that vitamin D deficiency is associated with a substantiallyincreased risk of all-cause dementia and Alzheimer disease.”
How does it work?
Given the chance (on a good day), vitamin D is made in the skin in the presence of sunlight, or rather, on exposure to solar ultraviolet B (UVB). It reacts with cholesterol, and produces cholecalciferol – vitamin D3. Vitamin D3 is converted to 25(OH)D (also known as calcidiol), the form of the vitamin that circulates in the blood.
It is this form that crosses the blood-brain barrier and binds to vitamin D receptors throughout the brain. And this is where it helps prevent dementia: part of its role is the clearance of amyloid beta (Aβ) plaques and neurofibrillary tangles created by tau proteins, both a hallmark of Alzheimer’s disease.
Vitamin D deficiency isn’t something that only becomes apparent in old age, in the form of dementia. There’s more than one good reason for you to consider supplementing with this hormone-like vitamin, well before senescence looms. The list of disorders associated with vitamin D deficiency is a long one, and includes osteoporosis, cardiovascular disease, cancer, stroke, diabetes, schizophrenia, psychosis and autism.
Sometimes, signs and symptoms make themselves felt at an early stage, before anything more serious appears. The early signs of vitamin D deficiency can include:
Fatigue
Frequent colds and infections
Poor wound healing
Brittle bones
Back ache
Hair loss
Deficiency is defined as serum 25(OH)D concentrations of less than 30 nmol/L. A score of over 50 nmol/L is considered adequate for bone and overall health.
Vitamin D deficiency affects up to 90 per cent of the elderly population. People over the age of 60 require three to four times more sun exposure than people under 20. That’s because our ability to make vitamin D in the skin reduces with age. Elderly people have decreased 7-dehydrocholesterol, a cholesterol precursor that is required to make vitamin D in the presence of sunlight.
We need all the reinforcement we can muster, because there are more than 50 million people around the world with dementia (a figure expected to almost triple by 2050) and up to one billion people with vitamin D deficiency.
I hope by now you are persuaded of the urgency of taking vitamin D supplements. But which ones? And how much? Below is what you should know before you make that choice.
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