There are many historical references to the role of food (and thus nutrition) in health, the most prophetic perhaps being Hippocrates, Let thy food be thy medicine, and thy medicine be thy food. Plants have been esteemed for their healing value for thousands of years. It was Charlegmane who stated A herb is a friend to physicians and the praise of cooks. Biblical references to food as medicine can be found in the book of Genesis As I did the green herb, I have given you all things (Genesis 9:3), and Ezekiels And the fruit thereof shall be for meat, and the leaf thereof for medicine (Ezekiel 47:12).
Nutritional interests and findings from 400 BC to AD 1750 included Hippocrates food as medicine school of thought, Harvey and Spallanzis observations in circulation and digestion, and Linds work with lemon juice or lime curing scurvy (now known to be due to Vitamin C deficiency). From 1750 to 1900 Lavosier, the father of nutrition, studied the relationship between calories, heat production, and oxygen use in the body, methods were developed to measure organic compounds in food, and theories began to develop on what an adequate diet must contain to be essential to life.
By the early 1900s, after numerous experiments of animals and humans failed to thrive on synthetic foods, it was well established that there were dietary essentials beyond carbohydrates, protein, fat, and minerals. These failed experiments lead scientists to the discovery of vitamins as essential to life- vita is Latin for life. It was around this time that nutrition was recognized as a distinct science and discipline with the founding of the American Institute of Nutrition in 1934.
By 1940, twelve vitamins, and many more minerals, had been identified as essential to humans, with the chemical structure and biological role having become more and more delineated. Once essential nutrients were identified the arduous, and ever changing, task of establishing how much of a particular nutrient is needed? became the common refrain (even until the present day).
Since 1950 many technological developments have allowed for the rapid expansion of the understanding of the role of nutrition on the growth, development, and maintenance of all aspects of life, and on the relationship between diet, nutrition, and disease. Emphasis in nutrition research has shifted from a search for essential nutrients to interrelationships among nutrients, precise biological roles, the determination of human requirements, universal analytical methods for determining nutritive values of food, and the effect of processing on the nutrient quality of foods. A shift of thinking also occurred from viewing nutrition solely at the chemical and molecular level to a desire for an understanding of the behavioral aspects that influence food intake in humans, and ways to utilize that understanding to improve the nutritional status of the public.
New concepts being studied include effect of nutrition on genetics, brain development and human behavior, immunity and resistance to infection, environmental factors such as pollution, alcohol, and drug use on detoxification. New approaches to the study of nutrition and its interrelationships with other sciences (cellular biology, microbiology, physiology, chemistry, medicine, genetics, and food science) have stimulated interest in the variation of individual needs and the nutritional influence on functional health as a means of balance restoring vs. problem avoiding (a functional medicine approach to nutrition).
When considering history, it is important to remember that history is in a constant state of flux, and is constantly being re-written. Nowhere is this more evident than in the dynamic field of the health sciences. As new research arises, it challenges the old models and paradigms. The health sciences are evolving. Nutrition is one of the cornerstones of an individuals health, and is one of the cornerstones of healthcare today.
How can the American diet be rated? The Standard American Diet (S.A.D.) is characterized all too often by monotony. The standard American is overfed, but undernourished. Food is plentiful in our global economy, but is often devoid of nutritional value due to its high degree of processing and refinement. It is no wonder that one in two American adults are obese or overweight (according to an article in the Journal of the American Medical Association dated October 27, 1999), and that six of the top ten causes of death are diet related. Food choices are based on what tastes best, not on what is the best choice for health. If not given the proper nutrients, the bodys normal functioning can become impaired. Over-reliance on the same foods can lead to sub-optimal intakes of nutrients (or at the opposite end of the spectrum, toxicity of certain nutrients and anutrients) and may eventually produce allergy or hypersensitivity to foods, further provoking a host of physiological and immune reactions that culminate in illness.
Heredity is considered to be a factor in the etiology of disease. This is particularly true if an individual makes the same unhealthy diet and lifestyle choices that their parents made. Thus, while heredity does play a role in the etiology of disease, diet and nutrition can modify the genetic predisposition to disease.