Vitamin C. Tendons and ligaments also need vitamin C, a nutrient found in many vegetables and fruits, because both tissues contain large amounts of collagen. Vitamin C plays an essential role in new collagen production, and a vitamin C deficiency can weaken your tendons and ligaments by preventing collagen synthesis.entils contain tendon-and ligament-healthy protein, as well as manganese and copper. Tendons and ligaments make up essential parts of your musculoskeletal system.