The season's most altruistic fruit? Citrus. Besides its own bright taste and vitamin C punch, it amps up the flavor and nutrition of other foods, too: Squirt lemon juice into your green tea to boost your brew's antioxidant quotient by up to 13 times. Toss orange slices into your spinach salad; vitamin C ups the amount of iron your body can absorb from the leafy greens.
