NUTRITION: Boost your immune system and fight colds with probiotics

Did you know about 70 percent of your immune system resides in your gut?

Probiotics are beneficial bacteria that live in our digestive tract and help digest food, synthesize vitamins and support our immune systems. Eating more foods packed with probiotics during cold and flu season may lessen the impact of the common cold. According to a systematic review, certain probiotics strains, Lactobacillus and Bifidobacterium were found to lessen the duration of respiratory infections in adults and children.

To maintain a healthy digestive tract and immune system, it's helpful to consume probiotic-rich foods or even take supplements. These foods contain live bacteria cultures or have been fermented with benign bacteria.

Fermentation has been used throughout history as a way to preserve food. But don't confuse fermentation with pickling. Both are forms of food preservation, but pickled food won't provide probiotic benefits.

Fermentation occurs when bacteria convert carbohydrates and sugars in whole food items (like vegetables or milk) to an acid that helps preserve the food. To get the maximum benefits from fermented foods, read product labels and choose only those that contain "active, live cultures." Raw and unpasteurized is best unless you have a compromised immune system.

Probiotic foods are easy to come by in supermarkets these days. You'll find them in the produce section. Select foods that have been refrigerated and say they have live cultures or have not been pasteurized since the heat of pasteurization kills the good bacteria. It's also simple and inexpensive to make probiotic foods at home.

Sources of probiotics include:

• Fermented vegetables: sauerkraut, kimchi, pickles, beets, carrots
• Fermented fruits: chutneys, jams, green papaya, pickled jackfruit
• Yogurt, kefir, sour cream, buttermilk with live and active cultures (pick plain and no added sugar)
• Kombucha, a fermented beverage
• Fermented condiments: homemade ketchup, relishes, salsas and pickled ginger
• Water kefir, coconut milk kefir
• Homemade coconut milk or cashew yogurt
• Beet kvass, a fermented beet juice
• Natto, miso, tempeh, and tamari sauce