Re-examining chemically defined liquid diets through the lens of the microbiome.

Trends in nutritional science are rapidly shifting as information regarding the value of eating unprocessed foods and its salutary effect on the human microbiome emerge. Unravelling the evolution and ecology by which humans have harboured a microbiome that participates in every facet of health and disease is daunting. Most strikingly, the host habitat has sought out naturally occurring foodstuff that can fulfil its own metabolic needs and also the needs of its microbiota, each of which remain inexorably connected to one another. With the introduction of modern medicine and complexities of critical care, came the assumption that the best way to feed a critically ill patient is by delivering fibre-free chemically defined sterile liquid foods (that is, total enteral nutrition). In this Perspective, we uncover the potential flaws in this assumption and discuss how emerging technology in microbiome sciences might inform the best method of feeding malnourished and critically ill patients.

Historical highlights of the development of enteral nutrition.

The most significant events and discoveries regarding the development of enteral nutrition (EN) dating back to 1500 BC are chronicled. A more detailed description and discussion of subsequent more recent progress during the past two decades is focused primarily on 3 of the most dynamic areas of endeavor: tight glycemic control; timing and combining of EN and total parenteral nutrition to meet early target nutrition goals in intensive care unit patients; and the role, advances, and future of immunonutrition. An abridged classification of solutions for enteral feeding, and a brief outline of key prudent oral dietary guidelines are also presented.

INCAP studies of vegetable proteins for human consumption.

This article describes the efforts of the Institute of Nutrition of Central America and Panama (INCAP) to develop a relatively low-cost vegetable protein mixture suitable as a complementary food for infants and young children. As it turned out, the resulting product became popular with older children and adults, and its superior nutritional benefits were widely recognized by the population. This effort led to broader studies by INCAP of the nutritional quality of vegetable protein mixtures, including raw materials, processing to convert them into human-grade products, product formulation, and commercialization.

An extraterrestrial sandwich: The perils of food in space.

Food was and is an essential component in human space exploration. If it had not proved possible to eat and digest in space, none of the long-term space missions of the last four decades would have been achievable. Every country that has sent an astronaut on a mission has used its national foods as a means of stating both their presence and their identity to their colleagues in the programme and their citizens at home: in space, as on earth, food has provided a means of asserting national culture. From the earliest missions, the US and USSR's differing attitudes to the programme have been reflected in the food provided and the respective administrations' approaches to feeding in space. The contrast between the US focus on space travel and the USSR's focus on space living is highlighted through their attitudes to the often vexed question of what astronauts and cosmonauts should be permitted to eat, illustrated by the corned-beef sandwich incident of 1965.

History of parenteral nutrition.

The concept of feeding patients entirely parenterally by injecting nutrient substances or fluids intravenously was advocated and attempted long before the successful practical development of total parenteral nutrition (TPN) four decades ago. Realization of this 400 year old seemingly fanciful dream initially required centuries of fundamental investigation coupled with basic technological advances and judicious clinical applications. Most clinicians in the 1950's were aware of the negative impact of starvation on morbidity, mortality, and outcomes, but only few understood the necessity for providing adequate nutritional support to malnourished patients if optimal clinical results were to be achieved. The prevailing dogma in the 1960's was that, "Feeding entirely by vein is impossible; even if it were possible, it would be impractical; and even if it were practical, it would be unaffordable." Major challenges to the development of TPN included: (1) formulate complete parenteral nutrient solutions (did not exist), (2) concentrate substrate components to 5-6 times isotonicity without precipitation (not easily done), (3) demonstrate utility and safety of long-term central venous catheterization (not looked upon with favor by the medical hierarchy), (4) demonstrate efficacy and safety of long-term infusion of hypertonic nutrient solutions (contrary to clinical practices at the time), (5) maintain asepsis and antisepsis throughout solution preparation and delivery (required a major culture change), and (6) anticipate, avoid, and correct metabolic imbalances or derangements (a monumental challenge and undertaking). This presentation recounts approaches to, and solution of, some of the daunting problems as really occurred in a comprehensive, concise and candid history of parenteral nutrition.

The history of enteral nutrition therapy: from raw eggs and nasal tubes to purified amino acids and early postoperative jejunal delivery.

Although enteral feeding therapy has existed since ancient Egypt, most of the major advances in enteral feeding techniques and formulas took place during the 20th century, including postpyloric tube placement in 1910; continuous and controlled delivery of liquid nutrition in 1916; feeding during surgery and modification of macronutrients in 1918; feeding via a pump in 1930; recognition of the importance of nutrition therapy during injury recovery and the addition of micronutrients and early postoperative feeding in 1940; the introduction of commercial products during the 1950s with chemically defined formulas following a decade later; and the development of modern formulas during the 1970s. The purpose of this review is to provide a historical account of enteral nutrition, including modes and routes of delivery, types of diet, and refinements in delivery techniques and formulas and to offer the history of the therapy as a resource for developing and improving enteral feeding techniques and therapies and implementing optimal patient care strategies.

Feeding the premature infant in the 20th century.

This article reviews the historical development of feeding the premature infant in the 20th century. It describes the early work determining the energy requirements of the preterm infant, the evolution of the use of human milk and its fortification for these infants, the development of special formulas for very-low-birth-weight infants and the various techniques/methods utilized including total parenteral nutrition.