For years, doctors have told the 10 million atrial fibrillation (AFib) patients in the U.S. to avoid drinking coffee. But the DECAF (Does Eliminating Coffee Avoid Fibrillation?) study, conducted by researchers in California and Australia, reveals that one cup or one shot of espresso daily (not more) has a very positive benefit.

Over six months, a group of 200 patients who had persistent AFib or a related condition known as atrial flutter reduced their risk of recurring episodes of AFib by 39%.

The researchers suggest that there are multiple reasons why that cup of joe is helping control the heart's rhythm:

• First, coffee can act as a diuretic, lowering blood pressure, which reduces the risk of AFib.

• Second, it contains polyphenols and other substances that reduce levels of inflammation markers such as C-reactive protein (CRP). Inflammation fuels AFib.

• Third, caffeine is associated with increased physical activity, which benefits heart health.

• Fourth, coffee may replace an unhealthy beverage such as a soda.

I’m a major fan of coffee for its wide range of health effects, from helping manage blood sugar to reducing the risk of Parkinson's, protecting your brain, and reducing your risk of death from heart, kidney, or liver disease.

But don't overdo it — and drink it black and sugar-free.