Written by Jessica Patella, ND. In a seven year study with 498 women, those with the highest vitamin D blood levels had 435% less Alzheimer’s disease.
Deficiency of vitamin D is common in older adults, affecting up to 90% of the elderly population (1). There is a plethora of research on the benefits of vitamin D, but now a human trial has shown vitamin D intake is associated with a lower risk of developing Alzheimer’s Disease (2).
At baseline, the study included women without a diagnosis of dementia or Alzheimer’s Disease. Vitamin D intakes of all participants were estimated using the food frequency questionnaire. Direct exposure to sunlight (face and hands) between 11am and 3pm was also taken into consideration, since the body can produce vitamin D from sun exposure (2).
After 7 years, 498 women (average age 79.8 +/- 3.8 years) remained in the study. The women were divided into three groups: No dementia, Alzheimer’s Disease, or other dementia (2), based on the onset of dementia within the 7 years. At the end of 7 years, 72.5% of women did not have dementia, 14.1% had symptoms of Alzheimer’s disease and 13.4% had other dementias (2).
Women who developed Alzheimer’s disease had lower baseline vitamin D intakes (average 50.3 +/- 19.3 micro grams/week; n=70) than women who did not develop dementia (average 59.0 +/- 29.9 micrograms/week; n=361) (p=0.027) (2). The women that developed Alzheimer’s disease also were less exposed to sun than those with no dementias or other dementias (2). There was no difference between women who did not develop dementia and those who developed other dementias (2).
The highest dietary intake (average of 104.38 +/- 27.7 micrograms/week) of vitamin D was associated with a decreased incidence of Alzheimer’s disease by 4.35 times, within the 7-year period (2). There was no association between the baseline dietary intakes of vitamin D and the onset of other dementias (2). The highest intakes of vitamin D that were associated with a lower risk of developing Alzheimer’s disease within 7 years corresponds to about 50mL of cod liver oil per week, or 7 oz of sardines or anchovies canned in oil per day (2, 3).
In conclusion, higher intakes of vitamin D were associated with a lower risk of developing Alzheimer’s disease among older women (2). Further research with placebo controlled trials and exploring the most effective dose of vitamin D seem to be warranted.
Source: Annweiler, Cédric, Yves Rolland, Anne M. Schott, Hubert Blain, Bruno Vellas, François R. Herrmann, and Olivier Beauchet. “Higher vitamin D dietary intake is associated with lower risk of Alzheimer’s disease: a 7-year follow-up.” Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences 67, no. 11 (2012): 1205-1211.
© The Author 2012. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
Posted May 11, 2012.
Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health.
References:
- Annweiler C, et al. Vitamin in the elderly: 5 points to remember. Geriatr Psychol Neuropsychiatr Vieil. 2011;9:259–267.
- 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 doi: 10.1093/Gerona/gls107.
- French Information Center on Food Quality: Food composition table 2008. Available at the Anses Table Ciqual website.
