What are the different eras in the history of nutrition?

Naturalistic Era

· 400 B.C.-1750 AD

· scientists and philosophers theorizing about the function of the body and its response to external factors such as food

· however little knowledge was gained during this period with respect to the science of nutrition

· Hippocrates hypothesized about the body's "innate heat"

· During the next 500 years, little happened in either the development of scientific knowledge or nutrition science.

Chemical-Analytical Era

· late 1700's

· was hallmarked by calorimeter(crucial to further understanding of heat energy) studies by Lavoisier

· Lavoisier discovered how food is metabolized by oxidation to carbon dioxide, water and heat

· This era brought with it new found knowledge of food composition and the role of foods in metabolism

· as well as the mechanistic processes involved in digestion and utilization of foods

· Liebig recognized that carbohydrates, proteins and fats are oxidized by the body and calculated energy values for each

Biological Era

· early 1900's

· marked with increasing understanding of the metabolic pathways as well as the roles of macro-nutrients, vitamins and minerals

· The "Biological Era" (1900-present) was founded on advances in chemistry,biochemistry and understanding of the metabolic pathways

· research had been done on energy exchange and on the nature of foodstuffs

· Nutrition science took a leap forward as evidenced by publication of the "laws of nutrition" by Langworthy

· Once understanding of macronutrients was developed and better tools developed, nutrition scientists turned attention to the understanding of micro-nutrients, mineral and vitamin nutrition

Cellular Era

· latter half of the 1900's

· Greater insight into the roles of nutrients in metabolism and their functions as co-factors for enzymes and hormones

· focused on understanding functions of essential nutrients and the roles of micro-nutrients (vitamins and minerals) as co-factors for enzymes and hormones and their subsequent roles in metabolic pathways

· The roles of carbohydrates and fats in diseases such as Diabetes and atherosclerosis were discovered and actual and potential mechanisms have been uncovered.