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Archived Comments for: Cognitive health begins at conception: addressing dementia as a lifelong and preventable condition

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  1. The traditional Asian diet and vitamin D may significantly reduce the risk of cognitive impairment and Alzheimer’s disease

    William B. Grant, SUNARC

    2 December 2013

    The paper by Barnett and colleagues made the important points that dementia is largely preventable and that proper diet contributes to cognitive health [1]. The Mediterranean-style diet that they proposed as a way to reduce risk of dementia has been associated with a 33% reduced risk of mild cognitive impairment and Alzheimer’s disease (AD) [2].


    Overlooked in their paper was consideration of the Asian diets. In 1996, it was reported that Japanese-American men in Hawaii had 2.5 times the prevalence of AD as native Japanese [3]. This finding led to an ecological study based on prevalence of AD in 11 countries and dietary supply factors with the finding that total fat and energy supply were significant risk factors for AD, while fish and cereals/grains were associated with reduced risk [4]. More recently, it was reported that AD rates in Japan for those over the age of 65 years increased from 1% in 1985 to 7% in 2008 [5]. An ecological study using these data and dietary supply data [6] found that the increases in AD rates in Japan were correlated with dietary changes 15-25 years prior to the rates [7]. The primary changes were reduced rice consumption and increased meat and other animal products. The traditional Japanese diet in the early 1960s derived about 40% of its energy from rice and only 15% from animal products, primarily seafood. Thus, a diet low in animal products seems to be associated with greatly reduced risk of developing AD.


    Another factor to consider is vitamin D. There is evidence based on comorbid diseases associated with dementia that higher serum 25-hydroxyvitamin D levels would reduce the risk of dementia [8]. This hypothesis is borne out in several recent studies [9-11]. To reach the 75-100 nmol/l level takes 1000-4000 IU/d vitamin D3 in the absence of ultraviolet-B irradiance.



    1.Barnett JH, Hachinski V, Blackwell AD. Cognitive health begins at conception: addressing dementia as a lifelong and preventable condition. BMC Med. 2013;11:246.

    2. Singh B, Parsaik AK, Mielke MM, et al. Association of Mediterranean Diet with Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review and Meta-Analysis. J Alzheimers Dis. 2013 Oct 28. [Epub ahead of print] 3. White L, Petrovitch H, Ross GW, et al. Prevalence of dementia in older Japanese-American men in Hawaii: The Honolulu-Asia Aging Study. JAMA. 1996;276:955-960.

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

    5. Dodge HH, Buracchio TJ, Fisher GG, et al. Trends in the prevalence of dementia in Japan. Int J Alzheimers Dis. 2012;2012:956354.

    6. Food and Agriculture Organization of the United Nations. FAOSTAT. 

    7. Grant WB. Trends in diet and Alzheimer’s disease during the nutrition transition in Japan and developing countries. J Alzheimers Dis. 2013 Sep 13. [Epub ahead of print] 8. Grant WB. Does vitamin D reduce the risk of dementia? J Alzheimers Dis. 2009;17:151-159.

    9. Soni M, Kos K, Lang IA, et al. Vitamin D and cognitive function. Scand J Clin Lab Invest Suppl. 2012;243:79-82.

    10. Balion C, Griffith LE, Strifler L, et al. Vitamin D, cognition, and dementia: a systematic review and meta-analysis. Neurology. 2012;79:1397-1405.

    11. Afzal S, Bojesen SE, Nordestgaard BG. Reduced 25-hydroxyvitamin D and risk of Alzheimer's disease and vascular dementia. Alzheimers Dement. 2013 Jul 18. doi:pii: S1552-5260(13)02425-4. [Epub ahead of print] 12. 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;31:617-622.

    Competing interests

    I receive funding from Bio-Tech Pharmacal (Fayetteville, AR), and the Sunlight Research Forum (Veldhoven) and have received funding from the UV Foundation (McLean, VA), the Vitamin D Council (San Luis Obispo, CA), and the Vitamin D Society (Canada).

    William B. Grant, Ph.D.

    Sunlight, Nutrition, and Health Research Center