Vitamin C Content of Apple Juice Introduction Complete lack of ascorbic acid (a.k.a Vitamin C) in the diets of humans and other primates leads to a classic nutritional disease, scurvy. This disease was widespread in Europe during the fifteenth and sixteenth centuries, but it is rare today. Ascorbic acid is widely distributed in nature, but it occurs in extremely high concentrations in citrus and green plants such as green peppers and spinach. Ascorbic acid can be synthesized by all plants and animals, with the exception of humans, other primates, and guinea pigs