Boost your immune system with these top 18 vitamin C-rich foods Keeping your immune system healthy is crucial, and one of the best ways to do this is by incorporating vitamin C-rich foods into your diet. Unlike supplements, these foods provide a range of other beneficial nutrients. Here are 18 foods that are high invitamin C and can help you meet your daily requirements. 1. Oranges   Oranges are a classic source of vitamin C. A medium-sized orange contains 70mg of vitamin C, covering 78% of your daily needs. Sumo Citrus varieties are even...