One medium lemon has 18 calories, no fat or cholesterol, only 10 milligrams of sodium and supplies 35% of the daily recommendation of Vitamin C. Approximately 95% of the fresh lemons produced in the U.S. are grown in California and Arizona. Always use non-reactive cookware, such as stainless steel, enamel or plastic, when cooking recipes containing lemons or lemon juice. Uncoated iron, copper and aluminum cookware can discolor food and leave a metallic taste.