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A recent survey conducted by the Harvard School of Public Health indicated that Alzheimer's disease is the second most feared disease after cancer; therefore, it is surprising that cancer research receives more than 10 times the amount in research funding than Alzheimer's. Yet it is estimated that there will be a 300 percent increase in Alzheimer's patients to more than 16 million by the year 2050.
Part of the problem is we don't really know what causes Alzheimer's, and as a consequence, most of the drugs currently used to treat Alzheimer's are simply guesses. Not surprisingly, they don't work very well. So Alzheimer's is definitely a disease where an ounce of prevention is worth a pound of "cure".
But the one thing we do know is that like diabetes and heart disease, there appears to be a strong inflammatory component associated with Alzheimer's (1). This would strongly suggest that an anti-inflammatory diet might be the best protection against Alzheimer's (and probably against diabetes and heart disease too).
So what exactly is an anti-inflammatory diet? Simply stated it is one that reduces the level of cellular inflammation in the body. Cellular inflammation is below the perception of pain so you can't feel it, but you can measure it. The best clinical marker we currently have is the ratio of two fatty acids in the body. One is called arachidonic acid (AA), and the other is called eicosapentaenoic acid (EPA). AA is the molecular building block for making powerful inflammatory hormones, whereas EPA is the molecular building block for making equally powerful anti-inflammatory hormones. The higher the AA/EPA ratio, the more cellular inflammation there is throughout the body, including the brain. It was shown a decade ago, using age-matched elderly subjects, that a high AA/EPA ratio in the blood was strongly associated with Alzheimer's and other cognitive impairments (2).
So what drug can you use to reduce cellular inflammation? The answer is none, since it can only be done through the diet and specifically an anti-inflammatory diet. A characteristic of an anti-inflammatory diet is following a low glycemic-load diet rich in vegetables and fruits, because they enter the bloodstream at a lower rate than grains or starches (3). This delayed entry of carbohydrates reduces the production of insulin. This, in turn, reduces the generation of arachidonic acid that drives cellular inflammation (3,4).
So does following such a diet work in clinical trials? The answer appears to be yes, as it was recently demonstrated that a low glycemic-load diet could improve the mental functioning in patients with mild-to-moderate mental impairment in as little as four weeks (5). This low glycemic-load diet would also reduce the production of AA, leading to a lower AA/EPA ratio. Simultaneously, you should also be able to lower the AA/EPA ratio by increasing EPA by eating more fish. Fish contains a combination of both EPA and another omega-3 fatty acid known as docosahexaenoic acid (DHA). Although EPA is a much more powerful anti-inflammatory agent than DHA, most clinical studies have studied primarily DHA instead of EPA. Not surprising, the results of those intervention trials have been lackluster at best (6,7). This is because DHA has little effect on changing the AA/EPA ratio, whereas EPA has a much greater effect in reducing cellular inflammation, especially in the brain. I have already demonstrated this in an animal study that showed that the reduction of the AA/EPA ratio with fish oil rich in EPA prevents more than 98 percent of the neural damage induced by concussions (8). So if you are going to take fish oil as part of an anti-inflammatory, low glycemic-load diet, just make sure it is rich in EPA.
With no new drugs on the horizon for the treatment of Alzheimer's, it appears the best course is prevention. Specifically this means maintaining a low glycemic-load diet rich in EPA for a lifetime. You can measure your success in the blood by measuring the AA/EPA ratio. It's good for the brain and heart, as well as for living a better and longer life.
References
McGeer EG and McGeer PL. Molecular Interventions 1:22-29 (2001)
Conquer JA et al. Lipids 35: 1305-1312 (2000)
Sears B. "The Zone." Regan Books. New York, NY (1995)
Sears B. "Toxic Fat." Thomas Nelson. Nashville, TN (2008)
Bayer-Carter JL et al. Arch Neurology 68: 743-752 (2011)
Freund-Levi Y et al. Arch Neurol 63: 1402-1408 (2006)
Quinn JF et al. JAMA 304: 1903-1911 (2010)
Mills JD et al. J Neurosurg 114: 77-84 (2011)
Dr. Barry Sears is a leading authority on the hormonal effects of food and their effects on inflammation. He is the author of the #1 New York Times best seller "The Zone" and has published more than 30 scientific articles. He is the president of the non-profit Inflammation Research Foundation. For more information on anti-inflammatory diets, please go to www.drsears.com.
