Fermented foods ... health benefits or hype?

Dear Mayo Clinic: Are there any special health benefits to fermented foods?

A: The jury's still out. In recent years, claims of possible health benefits of fermented dairy or plant foods, such as yogurt, kefir, aged cheese, tempeh, miso, sauerkraut and many others, have gained the spotlight.

The digestive tract is loaded with beneficial bacteria. Likewise, live, active bacteria make fermented foods possible. These bacteria, known as probiotics, are where the potential health benefits in fermented food may be.

While it sounds promising, the evidence is more suggestive than proved. Some evidence supports select probiotic use for certain bowel disorders. Research is ongoing to understand how probiotics may influence other areas of health, including obesity and regulation of the immune system.

To gain benefits, it's generally thought that a daily probiotic dose of around 10 billion colony-forming units (CFU) of certain bacteria strains is needed. However, fermented foods are all over the map in terms of the dose and type of beneficial bacteria. Some fermented foods contain supplemental probiotics to achieve a consistently high dose. Others might contain only moderate or low levels of live cultures - or no live cultures at all.

Fermented foods can be a part of a healthy diet and may provide health benefits that other foods can't. But, it's hard to say exactly what you're getting from a fermented food in terms of bacterial type or dose. Therefore, it's difficult to know what you can expect in terms of probiotic benefits. In addition, a fermented product with live active cultures also may contain high levels of saturated fat, salt or added sugars.