High levels of a particular amino acid or protein appear to significantly increase the risk of developing Alzheimer's disease. That's the finding of a study published in the this week in the New England Journal of Medicine.

The amino acid is homocysteine, which was found to be elevated in the blood of people who eventually developed Alzheimer's.

Researchers at Boston University measured levels of the protein in 1,100 elderly patients in 1980, 1990 and again in 2000. They found that those with the highest levels of the amino acid had twice the risk of developing the disease.

This is sort of exciting to us because unlike other risk factors for Alzheimer's like your age or your family history, homocysteine is something you can change by adopting a more healthy diet, said Sudha Seshadri, a Boston University neurologist and the study's lead author.

High homocysteine levels can be reduced by taking folic acid.

Dr. Seshadri says the next step is to do studies to see whether reducing homocysteine levels reduces the risk of Alzheimer's disease.