Subject: Both Vitamin B-3 and Statin drugs lower cholesterol. They may also prevent Alzheimer's Disease. Is there a connection?
An interesting article appeared in the August, 2004 issue of the Journal of Neurology, Neurosurgery, and Psychiatry which suggests that vitamin B-3, that's niacin, may protect people against Alzheimer's Disease. The US researchers looked at the diets of almost 4,000 people aged 65 and over between 1993 and 2002. None had any history of Alzheimer's disease. The researchers then monitored for any signs of decreasing mental agility. After three years, a sample of 815 people was checked for clinical changes and their dietary intake was assessed. Among this group, 131 were diagnosed with Alzheimer's disease. People who consumed the least niacin, 14.1 milligrams per day on average, were about three times as likely to develop Alzheimer's Disease as people who consumed 17 mg/day.  The US Department of Agriculture considers 14-16 mg per day as an adequate daily intake.
Niacin deficiency leads to a disease called pellagra - characterized by dementia, diarrhea and dermatitis - but the idea that niacin might play a role in Alzheimer's is new.
Niacin is a water soluble vitamin, absorbed from the intestinal tract. It's principle role in the body is as a constituent of two important enzymes: nicotinaminde-adenine dinucleotide (NAD) and nicotinamide-adenine dinucleotide phosphate (NADP). The amino acid Tryptophan can be converted into niacin in both animals and humans. The conversion rate is about 60 to 1. Early research was confused because foods high in tryptophan could cure pellagra. Niacin was identified as the “antipellagra factor” in 1937. In reading my college nutrition textbook, I was entertained to see an inordinate amount of space devoted to coffee being an excellent source of niacin.
Hold both of these thoughts for a second while we talk about Statin drugs.
Statins are a group of drugs which are used to lower cholesterol. Zocor and Lipitor are the most recognizable names. There have been reports that these drugs may prevent Alzheimer 's disease. 
In April of 2003, an article in the Archives of Neurology compared the effect of statins versus niacin in lowering the amount of cholesterol byproducts thought to contribute to Alzheimer's disease. Recent studies have indicated that blood levels of these substances are higher in people with Alzheimer's.
During the six-week study, 44 patients took one drug -- either a statin or niacin. Their blood was measured at the start, periodically throughout the study, and at the end.
Those taking statins had 21% lower levels of the cholesterol byproducts and 25% lower total cholesterol. Those taking niacin only had 10% reduced levels of the cholesterol byproduct.  This study used 1,000 mg/day of niacin in an attempt to lower cholesterol and decrease these cholesterol byproducts. This is not an excessive dose. We may use twice that dose with patients to lower cholesterol. The result is also not surprising. Niacin is slower acting than statins; at the six week cut off point of this study, the niacin would have only just begun to act.
Go back to the first study about niacin and Alzheimer's, the daily dietary consumption of niacin varied by relatively tiny amounts; the difference between high risk to low risk groups was only 17 mg to 14 mg. In other words, 3 mg a day made a significant difference. How do we view this with the 1,000 mg/day experiment I just mentioned?
The relationship between niacin, cholesterol and Alzheimer's is not quite figured out at this point. The evidence is growing. In the meantime a daily dose, and not a necessarily large one, of niacin may offer long term protection against Alzheimer's. A dose of Lipitor may do the same.
Back to coffee for a moment. There are about 10 mg of niacin per 100 grams of ground coffee. The amount varies with roasting. Light roast provides about 1 mg per cup of brewed coffee while a dark roast may have 3-4 times that level. Recall that a 3 mg per day increase in niacin consumption lowers the risk of Alzheimer's, it isn't surprising that a recent epidemiologic study suggested that coffee has a protective effect.  So while yo wait to hear whether you should take niacin or lipitor to prevent Alzheimer's Disease, you might as well have a cup of coffee.
 J Neurol Neurosurg Psychiatry. 2004 Aug;75(8):1093-9.
Dietary niacin and the risk of incident Alzheimer's disease and of cognitive decline.
Morris MC, Evans DA, Bienias JL, Scherr PA, Tangney CC, Hebert LE, Bennett DA, Wilson RS, Aggarwal N.
 J Clin Pharm Ther. 2004 Jun;29(3):209-13.
Do statins slow down Alzheimer's disease? A review.
Caballero J, Nahata M.
 Arch Neurol. 2003 Apr;60(4):510-5.
Reduction in levels of 24S-hydroxycholesterol by statin treatment in patients with Alzheimer disease.
Vega GL, Weiner MF, Lipton AM, Von Bergmann K, Lutjohann D, Moore C, Svetlik D.
 Am J Epidemiol. 2002 Sep 1;156(5):445-53.
Risk factors for Alzheimer's disease: a prospective analysis from the Canadian Study of Health and Aging.
Lindsay J, Laurin D, Verreault R, Hebert R, Helliwell B, Hill GB, McDowell I