Curing disease by administering food that would “restore the normal level of the deficient element.”

If one is fully cognizant of the reason for the incursion of disease and can determine the balance of elements, he can cure diseases by administering the food that can restore the normal level of the deficient element. In this way there will be no need for medicines and other difficulties will not arise. … Although animals do not know the science of medicine, why, when they are sick, do they abstain instinctively from what is injurious to them and eat foods that are beneficial, while man, when ailing, inclines more to that which is injurious to him? (Words of ‘Abdu’l-Baha, Mahmud’s Diary, p. 84)