Eating chocolate has now been found to be beneficial not harmful for those who have atrial fibrillation. Any report should be carefully checked to see the length of the study and who did it.
A friend told me her cardiologist said she should not eat chocolate. She was glad to know an article in the New York Times on 5/30/17 noted that in a "large Danish study, researchers found an association between chocolate consumption and a lowered risk for atrial fibrillation." The study was on 3,346 patients and lasted 14 years, so it was well done. "Those who ate chocolate two to six times a week had a 20% reduced risk." My friend was delighted with the report.
Like all medical studies, we need to look at who has done the research, where it was done and the number of cases in the study. Reports like Dr. Andrew Wakefield's on autism, can cause terrible harm, so any report should be carefully scrutinized. He reported on just a few cases and his report was retracted by the British journal that published it. He also lost his license to practice medicine in England and is now in Austin, Texas trying to re-start his medical career and still sending out erroneous autism information. The meeting he had with Trump in New York City raises questions about what they discussed. A single individual can cause unbelievable harm in the medical world, so we all have to look carefully at where we get our information and who has done the research. There is a great deal of misinformation on the Internet, but also excellent information on sites such as the Mayo Clinic.