Researchers from the National Institute of Drug Abuse proved that consuming marijuana limbers up the chances to develop heart diseases. It seems that smoking marijuana determines the body to produce a greater quantity of a protein that increases levels of blood fats, which are closely linked to heart attack and stroke. The study was published in the May 13 issue of Molecular Psychiatry.

“We've done a number of clinical papers reporting on marijuana users. In the past, we have reported cognitive abnormalities, and a paper in 2005 reported vascular [blood vessel] abnormalities," said Dr. Jean Lud Cadet, chief of the Molecular Neuropsychiatry Research Branch of the National Institute of Drug Abuse, as cited by

the U.S. News & World Report.

There were 18 long-term heavy users of marijuana and 24 nonusers involved in the study. With the help of a new electronic technology it was possible for the researchers to analyse the blood levels of a variety of proteins.

The outcome of the study revealed that marijuana users had higher blood levels of apolipoprotein C-III than the nonusers. APOC-III is one of a large family of proteins that interact with fats. It detains the breakdown of triglycerides, fats that can clog in blood vessels and favor formation of plaques, leading to blockages that can cause heart attacks, strokes and other problems.

"It is a risk factor for cardiovascular disease. The study suggests that APOC-III might be one of the risk factors contributing to the medical problems that marijuana users suffer from," said Cadet.

According to what the participants in the study said, they used to smoke 78 to 350 marijuana cigarettes per week.

The study doesn’t reveal any comparison between marijuana and tobacco smokers as regards these risks.

A U.S. group supporting legal sales and regulation of marijuana disagree with the researchers. Their argument is the fact that the people involved in the study were extremely heavy users and that the effects of such excesses are more than expectable, and not only when speaking of marijuana."I think the low end was 78 joints a week. That's 10 or 11 joints a day. We're talking about people who are stoned all the time. We're talking about the marijuana equivalent of the guy in the alley clutching a bottle of cheap wine. If you do anything to that level of excess, it might well have some untoward effects, whether it's marijuana or wine or broccoli," said Bruce Mirken, Marijuana Policy Project spokesman, as Reuters cites.