Scurvy easily, and once-healed breaks may recur. Defective collagen fibrillogenesis impairs wound healing. Untreated scurvy is invariably fatal. Diagnosis typically is based on physical signs, X-rays, and improvement after treatment. Scurvy can be prevented by a diet that includes vitamin C-rich foods such as amla, bell peppers (sweet peppers), blackcurrants, broccoli, chili peppers, guava, kiwifruit, and parsley. Other sources rich in vitamin C are fruits such as lemons, limes, oranges, papaya, and strawberries. It is also found in vegetables, such as brussels sprouts, cabbage, potatoes, and spinach. Some fruits and vegetables not high in vitamin C may be pickled in lemon
Vitamin A deficiency bind with opsin. Night blindness results. Night blindness caused by VAD has been associated with the loss of goblet cells in the conjunctiva, a membrane covering the outer surface of the eye. Goblet cells are responsible for secretion of mucus, and their absence results in xerophthalmia, a condition where the eyes fail to produce tears. Dead epithelial and microbial cells accumulate on the conjunctiva and form debris that can lead to infection and possibly blindness. Decreasing night blindness requires the improvement of vitamin A status in at-risk populations. Supplements and fortification of food have been shown to be effective interventions.