Researchers report that huge doses of an ordinary vitamin appeared to eliminate memory problems in mice with the rodent equivalent of Alzheimer's disease.

At the moment, there's no way to know if the treatment will have the same effect in humans. Researchers are beginning to enroll Alzheimer's patients in a new study, and scientists aren't ready to recommend that people try the vitamin on their own outside of normal doses.

Still, "it's definitely promising, and if we combine this with other things already out there, we'd probably see a large effect," said study author Kim Green, a researcher at the University of California at Irvine.

Alzheimer's disease affects an estimated 5.2 million Americans, causing senility and often leading to death. The Alzheimer's Association estimates that the disease will strike one in eight Baby Boomers.

There's no cure for the neurodegenerative condition, and medications have only limited effects.

In the new study, Green and colleagues looked at nicotinamide, a form of Vitamin B3 that is found in foods such as pork, peanuts, turkey, chicken, veal, fish, salmon, swordfish, tuna and sunflower seeds.

Previous research has suggested that vitamins such as Vitamin E, Vitamin C and Vitamin B12 may help people lower their risk of developing Alzheimer's disease, said Dr. Ralph Nixon, vice chair of the Alzheimer's Association Medical & Scientific Advisory Council.

In the new study, researchers genetically engineered mice to develop the equivalent of human Alzheimer's disease. They tested their memory by putting them in a shallow pool of water and seeing if they could remember the location of a platform that would allow them to emerge from the water.

The researchers then gave Vitamin B3 to some of the mice; the amount was equal to about 2 grams to 3 grams of the vitamin for humans, Green said. The mice were again tested in the pool.

The findings were published online Nov. 5 in The Journal of Neuroscience.

The forgetful mice who took the vitamin did well. "Cognitively, they were cured," Green said. "They performed as if they'd never developed the disease."

The vitamin appears to work by clearing "tangles" of a protein known as tau in brain cells. In Alzheimer's disease, the protein becomes poisonous and contributes to dangerous clogging inside brain cells.

The vitamin holds promise for people, because it's cheap -- Green bought a year's supply for $30 -- and appears to be safe. Even so, "until we've done the proper clinical trials, I wouldn't advocate people rush out and eat grams of this stuff each day," he said.

Nixon said the new study is "intriguing," but people should be cautious and not assume that "more is better" when it comes to possible treatments, even ones that appear to be safe.