A、Coffee drinkers with a lower version of the gene. B、Coffee drinkers with a faster version of the gene. C、People who drink coff

Narrator: First we heard medical studies saying that caffeine in coffee was probably bad for the heart, but recent research showed that coffee may be good for the cardiovascular system, that left coffee lovers like Corrine Mckillop to wonder.
Corrine Mckillop: I’d like to know which it is. It’s very confusing. Is it good or is it not good?  
Narrator: Well, a new study may explain the conflicting information. According to the research, coffee can be both good and bad. It all depends on you and which version of a gene you have.
Dr. Sean Kenniff: Researchers believe that about haft of us axe carrying a gene that allows the body to break down caffeine quickly. The rest of us have the type of gene that more slowly metabolizes the stimulant.
Narrator: In the study scientists discovered coffee drinkers with the faster version of the gene had no increased risk of heart disease; however, people with the gene that breaks down caffeine slowly had a significantly higher risk.
Dr. Sean Kcnniff: When the caffeine circulates in your body for a long period of time, you might in fact experience adverse health consequences from that. Now all of us want to know the same thing.
Corrine Mckillop: Well. I’d like to find out what gene I have.
Narrator: Well, that’s the bad news. There is a test to find out, but it probably won’t be readily available for a while. So what to do until then, the answer is, in a word--moderation. The study also found that people with a slower gene can limit their risk if they limit their coffee to one or two cups a day.