Natto is a soybean product that is sticky, slimy and smelly, but it might be able to ward off Alzheimer’s disease.

Once a theme ingredient on Iron Chef , natto contains an enzyme called nattokinase that can shred brain plaque, and chemists think it could become a game-changing medication.

In theory, the fermented soy substance would break up the deadly amyloid protein that forms fibrous deposits in the brains of Alzheimer’s patients.

"The ability of nattokinase to degrade amyloid fibrils is quite promising," says Li Gan, an Alzheimer’s expert at the Gladstone Institute for Neurological Disease. "Since the enzyme comes from a type of health food, it might have fewer side effects."

There is no cure for Alzheimer’s, a degenerative illness that affects more than

5 million people. Some drugs can provide a modicum of relief for people who suffer from moderate memory loss. But scientists need a better understanding of the disease, and a fresh strategy for treating it.

Chemist Rita Chen and her team at National Taiwan University showed that the soy enzyme can destroy three different types of toxic protein fibers. In a recent report to the Journal of Food and Agricultural Chemistry , they wrote that the experimental medicine can reach many parts of the body when taken orally, but it might not be able to enter the brain — the place where Alzheimer’s patients need it most.

But if the enzyme can work its magic in the brain, chemists will finally know how to undo the damage, rather than just treating the symptoms. But chopping up the protein fibers might make things worse.

"Breaking down the fibrils may not always be beneficial," says Gan. "For example, if the fibrils are broken down to smaller, non-fibrillar aggregates, they could be even more toxic."

For that reason, both Chen and Gan agree that it is time to test the enzyme on animals.

In the report, Chen pointed out that there may be an even simpler way to get some answers — an epidemiological study. If people who eat a high natto diet have a lower risk of getting the disease, she could be on to something.

The jury is still out on whether nattokinase will become a blockbuster Alzheimer’s drug. But it is is readily available in the freezer section of Japanese markets and often served with rice, sushi or pork. So you might want to develop a taste for the unusual food. But that could take awhile.

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Video: Iron Chef Natto Battle

Photo: Natto served on rice. toughkidcst/ Flickr