LOS ANGELES, Nov. 23 (Xinhua) -- U.S. researchers have discovered the reason why people who drink red wine largely avoid heart disease, and may have come up with a naturally-occurring substance that can partly reverse the effects of Alzheimer's disease, a new study showed.

    The researchers at the University of California in Los Angeles (UCLA) said the discovery will now be tested in human subjects, and could be the first disease-modifying treatment of Alzheimer's.

    The findings, published in the November issue of the Journal of Biological Chemistry, may explain why the typical diet in France, which is rich in bad cholesterol and saturated fats and copious amounts of red wine, does not lead to correspondingly high levels of heart disease or Alzheimer's there.

    "We believe this is an important next step," lead researcher David Teplow, a neurology professor, said in a statement released by the UCLA.

    Teplow and his team have measured how chemicals called polyphenols found in red wine block the formation of proteins that build up toxic plaque in the blood stream. This plaque has long been understood to clog arteries, and lead to Alzheimer's disease.

    Teplow and his colleagues examined 8,000 different types of polyphenols found in nature. Food such as cocoa, nuts, tea and berries contain polyphenols, and their link to plaque prevention has been long-understood.

    The new research, conducted at the UCLA and the Mt. Sinai School of Medicine in New York, is the first to explain the mechanics of how the various polyphenols work to combat plaque.

    Using lab mice, the researchers monitored how two types of proteins found in human blood can cause heart disease or Alzheimer's. These proteins fold up and stick to each other in the blood, killing nerve endings and leading to heart disease or Alzheimer's.

    Scientists used polyphenols distilled from grape seeds on the mice, and observed not only how the natural chemicals blocked the formation of the harmful proteins, but also reduced their toxicity, Teplow said.

    Teplow called the polyphenol's beneficial function "pretty straightforward" in blocking the proteins from converting into plaque-causing "toxic aggregates."

    "If the proteins can't assemble, toxic aggregates can't form, and thus there is no toxicity," Teplow said.

    This "suggests that administration of the compound in Alzheimer's patients might block the development of these toxic aggregates, prevent disease development and also ameliorate existing disease," he said.