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Dietary vitamin D intake and sun exposure linked to lower risk of Alzheimer’s in France
Posted: Wednesday, April 25, 2012 11:32 AM
Joined: 12/20/2011
Posts: 217



The following article is from The Vitamin D Council: 



Dietary vitamin D intake and sun exposure linked to lower risk of Alzheimer’s in France 



A paper published ahead of print on April 13 found that consumption of vitamin D-rich foods and midday sun exposure were associated with significantly reduced risk of developing Alzheimer’s disease [Annweiler et al., 2012]. The study was an add-on to the Epidemiology of Osteoporosis (EPIDOS) Toulouse cohort study at 43.6º N.


 Annweiler C, et al. Higher vitamin D dietary intake is associated with lower risk of Alzheimer’s disease: A 7-year follow-up. J Gerontol A Biol Sci Med Sci. 2012 Apr 13. 


This cohort included women over the age of 75 years at time of enrollment and was designed to study risk factors for hip fractures over a four-year period. Women who had taken vitamin D supplements in the 18 months prior to enrollment were excluded. Dietary factors and midday sun exposure habits were examined at time of enrollment. The mean dietary vitamin D intake was 334±172 IU/day. The presence of Alzheimer’s disease and other dementias was assessed seven years after enrollment.


Those in the highest fifth of vitamin D intake had one-quarter the incidence rate of Alzheimer’s disease as the other four fifths [odds ratio (OR) = 0.23 (95% confidence interval (CI), 0.08-0.69)]. In addition, those in the highest fifth of sun exposure had half the incidence rate of Alzheimer’s disease [OR = 0.45 (95% CI, 0.24-0.85)]. Neither dietary vitamin D intake nor sun exposure was significantly associated with risk of other dementia.


As mentioned in the paper, there is a considerable body of literature reporting that fish consumption is associated with reduced risk of Alzheimer’s disease, with the usual reason given that fish is an important dietary source of omega-3 fatty acids. This finding was likely first reported in an ecological study in 1997 [Grant, 1997]. Thus, it is not clear from the present study how much of the reduced risk of Alzheimer’s disease was due to omega-3 fatty acids and how much to vitamin D. 


However, the finding regarding sun exposure at midday strongly supports the role of vitamin D in reducing risk. Casual sun exposure in England for those aged 45 years is sufficient to increase serum 25-hydroxyvitamin D concentrations by 38 nmol/l (15 ng/ml) [Hyppönen and Power, 2007]. This increase is equivalent to about 1500-2000 IU/day [Garland, 2011]. However, for those over the age of 75 years, vitamin D production rates would be less, perhaps one-half as much [MacLaughlin and Holick, 1985].


Thus, this study provides good evidence that fish consumption and midday sun exposure reduce the risk of Alzheimer’s disease, with vitamin D being the likely agent. The neuroprotective actions of vitamin D are discussed in the paper by Annweiler et al. 



Annweiler C, Rolland Y, Schott AM, Blain H, Vellas B, Herrmann FR, Beauchet O. Higher vitamin D dietary intake is associated with lower risk of Alzheimer’s disease: A 7-year follow-up. J Gerontol A Biol Sci Med Sci. 2012 Apr 13. [Epub ahead of print]

Garland CF, French CB, Baggerly LL, Heaney RP. Vitamin D supplement doses and serum 25-hydroxyvitamin D in the range associated with cancer prevention. Anticancer Res 2011:31: 617-22.

Grant WB. Dietary links to Alzheimer’s disease. Alz Dis Rev 1997;2:42-55. (

Hyppönen E, Power C. Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr. 2007 Mar;85(3):860-8.

MacLaughlin J, Holick MF. Aging decreases the capacity of human skin to produce vitamin D3. J Clin Invest. 1985 Oct;76(4):1536-8.




Posted: Wednesday, April 25, 2012 11:58 AM
Joined: 12/20/2011
Posts: 217





This is The Vitamin D Council's multi-part article on Vitamin D deficiency, cognitive impairment, and dementia:

Cognitive impairment



Exposure to sunlight 


Vitamin D levels 

How does Vitamin D work?



[Links to 25 studies on Vitamin D and cognitive impairment]



Posted: Wednesday, April 25, 2012 12:14 PM
Joined: 12/20/2011
Posts: 217


More from the Vitamin D Council:


Mild Dementia


Lorenz from New York writes:


Dr. Cannell: My grandmother has had signs of early dementia for the last two years. I started giving her 5,000 units of vitamin D every day about six months ago. The results are amazing. Her memory is better, she no longer gets confused, and I can tell she feels better. She is on the way back to us! Is there any evidence that vitamin D can help dementia? Thanks for all you do.


Dr. Cannell replies:


There is no interventional evidence; that is, no one has given that amount of vitamin D to mildly demented patients to see if it helps. Remember, once the brain shrinks, as it does in dementia, vitamin D should have little effect. Important animal research recently showed activated vitamin D3 acts as a powerful anti-inflammatory agent and completely reverses the age-related increase in the inflammatory markers that accompany dementia, meaning they discovered the mechanism by which vitamin D may prevent dementia.

At least four studies have incidentally found that demented patients have low vitamin D levels. The obvious explanation is that demented patients dont go outside as much. However, Dr. Dhesi found associations between vitamin D and cognition within a narrow range of cognition, harder to explain by outdoor behavior. Dr. Flicker found the association, even after adjusting for outdoor exposure, suggesting causation.

Recently the Australians showed that multiple areas of the human brain contain both the vitamin D receptor and the ability to activate vitamin D into the powerful steroid hormone, calcitriol. This means vitamin D therapy may have implications for a wide variety of neurological and psychiatric illnesses. I'm glad your grandmother is better but I'm not surprised. One of the doctors I work with noticed similar improvements with his mildly-demented mother. 


[My comment:  Before giving anyone large doses of vitamin D, it's probably wise to have their vitamin D level tested.  It's a simple blood test that a doctor can order.  There are also home test kits that can be purchased over the internet.]

Lane Simonian
Posted: Thursday, April 26, 2012 9:36 AM
Joined: 12/12/2011
Posts: 5129

Thanks for the excellent information, Onward.  Here is one reason why Vitamin D may help in the prevention and treatment of Alzheimer's disease. 


Sunshine and Vitamin-D helps to Eliminate Mercury

Accumulating data have provided evidence that vitamin D is involved in brain
function. Vitamin D can inhibit the synthesis of inducible nitric oxide synthase
and increase glutathione levels, suggesting a role for the hormone in brain

The study shows that vitamin D helps remove mercury from your body safely
by radically increasing the amount of intracellular glutathione.

Neuroprotective and immunomodulatory effects of this hormone have also
been described in several experimental models, indicating the potential value
of vitamin D in helping neurodegenerative and neuroimmune diseases. In
addition, vitamin D induces glioma cell death, making the hormone of
potential interest in the management of brain tumors.

These results reveal previously unsuspected roles for vitamin D in brain
function and suggest possible areas of future research.

* Trends in Endocrinology and Metabolism April 2002,Volume 13, Issue 3, 1, Pages

Posted: Thursday, April 26, 2012 12:29 PM
Joined: 1/3/2012
Posts: 189

I always new this. My PCP has always looked at my vitamin D, and B12 levels. The frequent blood tests he does. He said a low level of either can affect memory. I take vitamin D3 supplements.