Think yogurt in a glass. This drinkable fermented dairy beverage is packed with beneficial probiotics that may help give your immune system a little extra edge, plus 29 percent of your daily value of calcium per 8-ounce serving. Look for it in your supermarket’s dairy section; choose plain for less sugar and fewer calories or fresh fruit flavors, such as peach and raspberry, for extra taste. Try kefir in this Banana-Spice Smoothie recipe.