Early concepts of nutrition, digestion, diseases of the gastrointestinal tract and their treatment: from Hippocrates and Galen to Maimonides

For over a thousand years, Hippocrates and Galen have been the Alpha and Omega of medical knowledge. Despite the importance of their contributions to clinical and theoretical medicine, they lacked a true understanding of anatomy and physiology. Hippocrates is commonly associated with proposing the doctrine of «tissue fluids», or humoral pathology, and his book, «On the Nature of Man», promotes this point of view. Galen became inherited the knowledge of Hippocrates. Ultimately, he was recognized as one of the most influential physicians of all time. The number of his works was enormous: he wrote more than a hundred books, which were widely distributed. One of Galen’s main commandments was the rule of harmony: all body systems are balanced; disease is a result of an imbalance. As one might expect, some of his ideas, however, were erroneous. Aristotle considered the pancreas, due to its location in the abdominal cavity, as an organ which only task was to protect the adjacent vessels. In an era when unknown diseases wreaked havoc, the concept of known causes of diseases led to the fascination with the study of food poisons and their antidotes. This was common among aristocracy who felt particularly vulnerable to this kind of threats. According to legend, one of the most famous connoisseurs of poisons was Mithridates VI. Pedanius Dioscorides was a Greek who served in the Roman army during the reign of the emperor Nero. The wandering nature of life led him to study a large number of diseases and medicines. The catalogue of his medicinal herbs and plants became the basis for the study and understanding of the medicinal properties of plants. Liver was considered the source of divine prophecy in many ancient cultures. The anatomy of liver was well known in ancient Babylon: a huge number of clay tablets and objects were left, which testify to the importance of «hepatoscopy» in the Middle East as a form of prediction. Those who used the insides of animals for divination (e.g., haruspices — divine interpreters of the future, using the liver as a prediction tool), could be considered the first official anatomists, since the understanding of the future depended on accurate knowledge and interpretation of certain liver components. After the victory of the Assyrian king Sargon over the forces of Urartu and Zikirti in 718 BC, Sargon wanted to appease the gods by sacrificing animals; in doing so, he studied their livers for predictions. Although the concept of pancreas is rooted in ancient times, as evidenced by the comments of haruspices and priests, knowledge of the organ functions eluded humanity until the works by Danish physiologists Francis Sylvius and Regnier de Graaf. Prior to their studies of pancreatic secretion and the elucidation of the role of pancreas in digestion, described by van Helmont and Albrecht von Haller, most researchers focused on the anatomical description of the organ. If the ancient Assyrians and Mesopotamians did not believe that liver predicts the future, but believed that it was pancreas that did it, then pancreatology may have earlier origins. Maimonides, a Jewish scholar and humanist, was also influential in other fields: he condemned astrology and its attempts to calculate the time of the Messiah’s coming. In the field of medicine, he paid attention to prevention, and was interested in the treatment of diseases of the gastrointestinal tract. By the beginning of our era, ideas about digestion, diseases of the digestive tract and their treatment remained very vague. There was a long and difficult way ahead in this area.