Some studies have indicated that non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and aspirin may delay the onset, and lower the ultimate risk, of Alzheimer’s disease. According to population studies, low but consistent daily NSAID used over a period of years such as ibuprofen (Advil, Motrin) seems to slow the progress of Alzheimer's. It seems that NSAIDs may affect the onset of the disease but is of little use for treating it once it has progressed to early or full-blown Alzheimer's.

It should be noted that some drugs such as acetaminophen, naproxen, and COX-2 inhibitors, such as celebrex and vioxx, were found to have no demonstrated benefit (and some evidence of cardiac harm). This ineffectiveness and the increase in adverse cardiac events associated with these agents was reported in various studies in 2004, and highlights the key role of ibuprofen in the original studies showing moderated risk associated with NSAID use (PMID 15720180).

A study (Archives of Neurology 2004; 61:82-88. PMID 14732624) has reported that the combination of vitamins E and C might, over time, sharply reduce the risk of Alzheimer's disease. Marked reduction (up to 80% risk reduction) was achieved after a period of more than five years, but only if dosage was 400 i.u. per day of vitamin E plus 500 mg or more per day of vitamin C. Lesser amounts, such as those found in multivitamin pills, appeared markedly less effective. Large doses of vitamin E without vitamin C had only a mild effect, while large doses of vitamin C without vitamin E had no benefit. However in one small study, 2000 i.u. per day of vitamin E did appear to delay the progression of early Alzheimer’s by several months. Other evidence suggests that vitamin E becomes a damaging pro-oxidant if given in isolation (without other antioxidants). Vitamin E can be recharged after absorbing a free radical by another antioxidant such as vitamin C or Alpha-lipoic acid. Some studies suggest that a ratio of at least 1000 mg of vitamin C to 400 i.u. of vitamin E is ideal. Recent studies suggest that the most common forms of E sold in supplements, the dl-alpha or d-alpha tocopherol form, are of little value, and that the gamma form of vitamin E, or a mixture of all the tocopherols and tocotrienols that collectively make up vitamin E from food, provide the most benefit. Vitamin E is markedly less effective unless taken with oil.

Improved nutritional status of the B vitamin folic acid was found to reduce Alzheimer's incidence in a study of an order of nuns, many of whom volunteered to have their mental status assessed and donated their brains for study after death. The "Nun's study" also revealed nuns who, in life, showed little or no dementia, but upon autopsy were found to have extensive Alzheimer’s plaques. The unimpaired nuns’ brains were free of evidence of stroke, including micro-strokes. Nuns whose brains revealed both plaques and stroke damage, however, were severely impaired in functioning while alive. Thus avoidance of risk factors for stroke may be a key element in preventing final progression to being disabled by Alzheimer's dementia. The discovery of the co-founding role of stroke supports other research showing that quitting smoking, weight reduction, and avoidance of diabetes all reduce Alzheimer's risk. Diabetes greatly increases Alzheimer's risk, and one factor at work may be that the enzyme charged with removing excess insulin from the blood, the Insulin Degrading Enzyme (IDE), also has the responsibility for removing Beta-amyloid plaques from the brain. Perhaps the excess insulin involved in the pre-diabetic metabolic syndrome, as well as insulin used to treat existing diabetes, may demand more IDE than the body is able to produce, leaving none to remove accumulating beta amyloid plaques from the brain.

Some evidence suggests that Alzheimer's risk may also be reduced by inclusion of certain kinds of fish in the weekly diet. Those that contain Omega-3 fatty acids are thought to most effective.

The natural chemical curcumin, found at 5% concentration in the spice turmeric, reduces Alzheimer's incidence in a mouse model and actually dissolves human senile plaques (beta amyloid) in the test tube (PMID 15590663). These factors suggest that inclusion of a bit of turmeric or curry spice in the diet may provide preventive value. Near 100% curcumin extract capsules are also available. Curcumin is a powerful antioxidant and a powerful anti-inflammatory. In India, where turmeric is commonly consumed in curry spices, Alzheimer's disease afflicts only approximately 1% of the elderly, whereas in the U.S. a much larger percentage are afflicted.

There may be a connection between the cholesterol level inside the brain cells and the deposition of the toxic amyloid plaques which make the brain cells die. In addition to lowering cholesterol, the so-called statins (drugs such as lovastatin, simvastatin, etc.) may have a beneficial role in reducing inflammation. However, retrospective studies into possible protective effects of statin drugs as a means of preventing or delaying Alzheimer’s have been inconclusive; no protective effect was found in one large prospective observational study (Arch Neurol. 2005;62:1047-1051. PMID 16009757).