This article p90x nutrition guide portion approach pdf about Nutrition in general. For Nutrition in humans, see Human nutrition. For Nutrition in animals, see Animal nutrition.
Nutrition is the science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism. The diet of an organism is what it eats, which is largely determined by the availability and palatability of foods. Hippocrates lived about 400 BC, and Galen and the understanding of nutrition followed him for centuries. The first recorded dietary advice, carved into a Babylonian stone tablet in about 2500 BC, cautioned those with pain inside to avoid eating onions for three days. According to Walter Gratzer, the study of nutrition probably began during the 6th century BC. In China, the concept of qi developed, a spirit or “wind” similar to what Western Europeans later called pneuma.
The first recorded nutritional experiment with human subjects is found in the Bible’s Book of Daniel. Daniel and his friends were captured by the king of Babylon during an invasion of Israel. Selected as court servants, they were to share in the king’s fine foods and wine. Salt, pepper and other spices were prescribed for various ailments in various preparations for example mixed with vinegar. One mustn’t overlook the doctrines of Galen: In use from his life in the 1st century AD until the 17th century, it was heresy to disagree with him for 1500 years. James Lind conducted in 1747 the first controlled clinical trial in modern times, and in 1753 published Treatise on Scurvy.
In the 1500s, Paracelsus was probably the first to criticize Galen publicly. Also in the 16th century, scientist and artist Leonardo da Vinci compared metabolism to a burning candle. Sometimes forgotten during his life, James Lind, a physician in the British navy, performed the first scientific nutrition experiment in 1747. Lind discovered that lime juice saved sailors that had been at sea for years from scurvy, a deadly and painful bleeding disorder. By containing his assistant, Armand Seguin, inside a rubber suit fitted with a tube sealed to his mouth with putty, Antoine Lavoisier first measured basal metabolic rate. Around 1770, Antoine Lavoisier discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat. In 1790, George Fordyce recognized calcium as necessary for the survival of fowl.
British sailors and Japanese naval officers did not. In 1896, Eugen Baumann observed iodine in thyroid glands. In 1897, Christiaan Eijkman worked with natives of Java, who also suffered from beriberi. Frederick Hopkins discovered vitamins, for which he shared a Nobel prize with Eijkman. In the early 20th century, Carl von Voit and Max Rubner independently measured caloric energy expenditure in different species of animals, applying principles of physics in nutrition. Oxford University closed down its nutrition department after World War II because the subject seemed to have been completed between 1912 and 1944.
In 1912, Casimir Funk coined the term vitamin, a vital factor in the diet, from the words “vital” and “amine,” because these unknown substances preventing scurvy, beriberi, and pellagra, were thought then to be derived from ammonia. The vitamins were studied in the first half of the 20th century. In 1925, Hart discovered that trace amounts of copper are necessary for iron absorption. In 1927, Adolf Otto Reinhold Windaus synthesized vitamin D, and was awarded the Nobel Prize in Chemistry in 1928. In the 1930s, William Cumming Rose identified essential amino acids, necessary protein components that the body cannot synthesize. In 1935, Underwood and Marston independently discovered the necessity of cobalt. In 1940, rationing in the United Kingdom during and after World War II took place according to nutritional principles drawn up by Elsie Widdowson and others.