To ensure that they get enough vitamin C each day, senior citizens should consume a lot of citrus fruits. Antibodies are known to be produced by vitamin C, which in turn strengthens the immune system and assists those over the age of 60 in warding off diseases. Oranges, broccoli, tomatoes, bell peppers, tangerines, grapefruit, and strawberries are just some of the examples of foods that are high in vitamin C content.