Overlooked B-vitamin might prevent Alzheimer's disease

In the hunt for substances that might prevent Alzheimer's disease, the focus has mainly been on antioxidants such as vitamin E and Ginkgo biloba plus the B-vitamins B12, -B6, and folic acid. However, an American study now indicates that the rather unheeded B-vitamin niacin also might be important in this context. For 90 years, it has been clear that niacin is important to the nervous system and that severe niacin deficiency can cause dementia - as part of the deficiency disease pellagra. The wonder is that, until now, nobody has made a link between this kind of dementia and Alzheimer's disease.
So far, the study has involved 6158 inhabitants of Chicago. They were all above 65 years of age and the plan was to register their diet and follow them every third year with psychological tests for dementia. They succeeded in doing so with 3718 of the trial subjects. Among these, 815 people who did not have Alzheimer's disease at the beginning of the trial were randomly chosen. They were divided into five groups according to their intake of niacin.
131 people in the latter group were diagnosed with Alzheimer's disease during the following four years. It turned out, however, that in the 20% who had the lowest intake of niacin (on average 12.5 mg. a day), the incidence of Alzheimer's disease was more than three times as high compared to the ones with the highest intake (22.4 mg. a day or more). This was the result after statistical adjustments for known or suspected causes of the disease had been performed.
Both dietary niacin and niacin from vitamin tablets were included in the study. Good dietary sources of niacin are whole meal, liver, meat, fish, milk, legumes, - and coffee! Brewer's yeast is also a good source of niacin, but, unfortunately, the same does not apply for beer! The average Englishman gets 2/3 of his niacin from meat, beverages, milk, and cheese, while only 1/8 comes from vegetables.
References:
1. Morris MC, Evans DA, Bienias JL, Scherr PA, Tangney CC, Hebert LE, Bennett DA, Wilson RS, Aggarwal N. Dietary niacin and the risk of incident Alzheimer's disease and of cognitive decline. J Neurol Neurosurg Psychiatry. 2004;75(8):1093-9.
2. The Danish Food authorities: Nutrient recommendations (1992).