Cucumbers were first introduced to North America by Christopher Columbus, and today they make up a staple in many Americans' diets. Their high-water and low-calorie content -- cucumbers are more than 95 percent water by weight and contain just 16 calories per cup -- make cucumbers a smart addition to a calorie-controlled diet, and they offer health benefits because of their nutrient content. Cucumbers, however, also come with a risk of oral allergy syndrome, so they can cause side effects in some people.