Longevity science

Probiotics, believed to help with digestion, are increasingly being studied to treat wide-ranging conditions, from colic to cholesterol and the common cold.

One of the fastest-growing dietary supplements, probiotics are now prominent on drug and big-box store shelves. They are live microorganisms—or "good" bacteria—that when consumed in capsules or yogurt are said to confer a health benefit.

New research suggests that in many people, heartburn may be caused by something other than acid reflux. But gastroenterologists are often stumped as to what it is and how to treat it.

Some 44% of Americans have heartburn at least once a month, and 7% have it daily, according to the International Foundation for Functional Gastrointestinal Disorders. Heartburn that frequent is the most common symptom of gastroesophageal reflux disease, a diagnosis believed to be rising world-wide with obesity and advancing age.

One 2004 study cited a 46% increase in GERD-related visits to primary-care physicians over a three-year period alone.