Scurvy, formerly associated primarily with long sea voyages and polar expeditions, is still common in areas where drought has destroyed fruit and vegetable crops. A decline in the habit of breast-feeding infants has also led to an increased susceptibility to scurvy.
Daily consumption of vitamin C reduces the duration and severity of cold symptoms and cold sores in those with recurrent outbreaks. It is therefore likely that a deficiency of vitamin C increases the risk of colds and cold sores. Long term supplementation (10 years or more) also reduces the risk of cataracts.