Nutrition, nourishment, or aliment, is the supply of materials - food - required by organisms and cells to stay alive. In science and human medicine, nutrition is the science or practice of consuming and utilizing foods.
In hospitals, nutrition may refer to the food requirements of patients, including nutritional solutions delivered via an IV (intravenous) or IG (intragastric) tube.
Nutritional science studies how the body breaks food down (catabolism) and repairs and creates cells and tissue (anabolism) - catabolism and anabolism = metabolism. Nutritional science also examines how the body responds to food.
Brigham Young University states1 that "nutritional Science investigates the metabolic and physiological responses of the body to food and diet, including the role of nutrients in the cause, treatment, and prevention of disease."
Contents of this article:
- What is nutrition?
- Brief history of nutrition
- What is the difference between a dietician and a nutritionist?
- Everyone in medicine is involved in nutrition
- The human body requires seven major types of nutrients
- Foods that protect against cancer and other diseases
- How salty foods may increase sugar intake
- Nutrition in medical education
What is nutrition?
As molecular biology, biochemistry and genetics advance, nutrition has become more focused on the steps of biochemical sequences through which substances inside us and other living organisms are transformed from one form to another - metabolism and metabolic pathways.
Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet.
Recent nutrition developments from MNT news
Five fruit and veggies a day helps you live longer - researchers from the Karolinska Institute, Sweden found that people who ate their "five-a-day" portions of fruit-and-veggies tended to live longer than those who did not. Their findings were published in the American Journal of Clinical Nutrition (July 2013 issue).2
The researchers said that for those who went a step further and had more than five portions per day, there appeared to be no additional benefits in terms of longer lifespans.
A large breakfast promotes weight loss - scientists from Tel Aviv University, Israel, wrote in the journal Obesity3 that a large breakfast - containing 700 calories - promotes weight loss and lowers the person's risk of developing heart disease, highcholesterol and diabetes.
Prof. Daniela Jakubowicz and colleagues emphasized that when we eat our food has a considerable impact on how our bodies process food.
Nutrition - a brief history
The Bible, Book of Daniel - Daniel was captured by the King of Babylon and had to serve in the King's court. Daniel objected to being fed fine foods and wine, saying he preferred vegetables, pulses and water. The chief steward reluctantly agreed to a trial, comparing Daniel's dietary preference to those of the court of the King of Babylon. For ten days Daniel and his men had their vegetarian diet, while the King's men had theirs. The trial revealed that Daniel and his men were healthier and fitter, so they were allowed to carry on with their diet.
Hippocrates (Greece, ca460BC - ca370BC), one nutrient theory - according to Hippocrates everybody is the same, no matter what they have been eating, or where they have lived. He concluded that every food must contain one nutrient which makes us the way we are. This one-nutrient myth continued for thousands of years. Hippocrates is also famous for having said "Let thy food be thy medicine and thy medicine be thy food."
Antoine Lavoisier (France, 1743-1794) - became known as the father of chemistry and also the father of nutrition. He became famous for the statement "Life is a chemical process". He also designed the "calorimeter", a device which measured heat produced by the body from work and consumption from different amounts and types of foods. At the age of 24 he became a member of the French Academy of Science. In 1794, during the French Revolution, he was beheaded.
Christiaan Eijkman (Holland, 1858-1930) - a famous physician and pathologist (doctor who identifies diseases by studying cells and tissues under a microscope). He noticed that some of the people in Java developed Beriberi, a disease which leads to heart problems and paralysis. When he fed chickens a diet consisting mainly of white rice they also developed Beriberi type symptoms, but the chickens fed unprocessed brown rice did not. White rice has the outer bran removed, while brown rice does not. When he fed brown rice to patients with Beriberi they were cured. Many years later it was found that the outer husks (outer bran) in rice contain thiamine, or vitamin B1. Together with Sir Frederick Hopkins, he received the Nobel Prize for Physiology/Medicine.
Dr. James Lind (Scotland, 1716-1794) - a pioneer on hygiene in the Scottish and Royal (British) navies. He stressed the importance of good ventilation, cleanliness of sailor's bodies, clean bedding, below deck fumigation, fresh water by distilling sea water, and the consumption of citrus fruits to prevent and cure scurvy. He is well respected today for his work in improving practices in preventive medicine and improved nutrition. He published his Treatise on Scurvy. Many decades later British sailors were known as Limeys because they regularly consumed lime juice and enjoyed better health and vigor than sailors in most other navies.
Dr. William Beaumont (USA, 1785-1853) - a surgeon in the US Army. He became known as the Father of gastric physiology for his research on human digestion. Beaumont met Alexio St. Martin, a French trapper who was shot in the stomach. Beaumont treated him but was unable to close the hole in his stomach, which healed with an opening to the outside (a fistula). St. Martin allowed Beaumont to make observations periodically, even allowing him to fiddle around with his innards, which must have been painful. This allowed Beaumont to conduct several experiments and make some important discoveries and conclusions, including:
- The stomach is not a grinder.
- There is no internal "spirit" selecting good purpose foods one way and discarding bad purpose foods to waste.
- Digestion occurs because of digestive juices which are secreted from the stomach.
- Foods are not digested separately and sequentially, but rather all the time and at different rates.
- Stomach rumblings are caused by stomach contractions, and nothing else.
- Fat is digested slowly.
Dr. Stephen Babcock (USA, 1843-1931) - an agricultural chemist. He is known for his Babcock test which determines dairy butterfat in milk and cheese processing. He is also known for the single-grain experiment that eventually led to the development of nutrition as a science.
Babcock had the idea of feeding dairy cattle with just one food source, either all corn plant or all wheat plant. He placed two heifers on either diet. However, when one of his animals died they were all taken away and he was not allowed to continue researching.
Eventually, Babcock's associates, Hart, Humphrey, McCollum, and Steenbock conducted the experiments again. Four five-month-old heifers were each fed either exclusively feed from corn plant, wheat plant, oat plant, or all three mixed together. They all put on weight at approximately the same rate during the first 12 months. However, the corn-fed cows went on to have normal calves, while the wheat-fed cows gave birth to either dead calves or calves that died soon after birth. They also noted that the corn-fed cows produced three times as much milk as the wheat-fed ones.
They concluded that either the wheat contained something that was bad for the cows or the corn had an essential nutrient that wheat did not have.
A succession of discoveries eventually found that something in the fat soluble portion of the corn affected reproduction. The scientists called this factor A - What we know today as Vitamin A.
Kazimierz Funk (Poland,1884- 1967) - a biochemist. Funk mistakenly thought these new things being discovered, such as factor A contained animes. As these animes were vital, he coined the term vitamins (vital animes).
As research evolved and further active properties were found, the water soluble ones were labeled B. It became obvious that more than one thing was involved in the water soluble substance, leading to the labels B1, B2, B3, etc. Some turned out not to be vitamins, while others were found to be the same as others - this explains why B vitamin numbers suddenly jump from 9 to 12, or 7 to 9. Vitamin B12 was discovered in 1948 by Karl A. Folkers (USA) and Alexander R. Todd (UK) and reported in 1949. They isolated the active ingredient, a cobalamin. It could also be injected straight into muscle as a treatment for pernicious (potentially fatal) anemia.
Vitamin C was clarified thanks to research carried out with guinea pigs. Very few animals, including humans, guinea pigs, primates, some bats, some birds, and some reptiles require vitamin C from food - all other animals are able to synthesize it internally (produce it themselves).
The era of discovering disease-preventing essential nutrients ended in 1948/49 with the discovery of Vitamin B12. Some other substances have since been discovered outside this "era" of great discoveries.
Some other famous people in the history of nutrition:
- 1925 - Edwin B. Hart discovered that trace amounts of copper are essential for iron absorption.
- 1927 - Adolf Otto Reinhold Windaus synthesized Vitamin D, for which he won the Nobel Prize in Chemistry.
- 1928 - Albert Szent-Györgyi isolated ascorbic acid (Vitamin C). In 1932 he proved that it was Vitamin C by preventing scurvy. In 1937 he synthesized Vitamin C and won the Nobel Prize.
- 1930s - William Cumming Rose identified essential amino acids which the body cannot synthesize, but which are necessary protein components.
- 1935 - Eric John Underwood and Hedley Marston discovered the necessity of cobalt. They were not working together - the discoveries were made independently.
- 1936 - Eugene Floyd Dubois demonstrated that school and work performance are linked to caloric intake.
- 1938 - Erhard Ferhnholz discovered the structure of Vitamin E, which was later synthesized by Paul Karrer.
- 1940 - Elsie Widdowson drew up the nutritional principles for rationing which took place in the United Kingdom during and after World War II. Widdowson also oversaw the government mandated addition of vitamins to food during World War II and some post-war years. Widdowson and Robert McCance coauthored The Chemical Composition of Foods in 1940, which became the basis for modern nutritional thinking.
- 1941 - The National Research Council (USA) set up the first RDAs (Recommended Dietary Allowances).
- 1968 - Linus Pauling coined the term orthomolecular nutrition. He proposed that by giving the body the right molecules in the right concentration - optimum nutrition - these nutrients would be better utilized and provide superior health and contribute towards longer lives. Pauling's work was the basis for future research which eventually led to large intravenous doses of Vitamin C for improving survival times and quality of life of some terminal cancer patients. Pauling was awarded the Nobel Prize in Chemistry.
- 1992 - the Department of Agriculture (USA) set up the Food Guide Pyramid, which was to be subsequently criticized by nutritionists throughout the world for different reasons.
- 2002 - a link between violent behavior and nutrition was revealed in a Natural Justice study (USA).
- 2005 - researchers found that the adenovirus is a cause of obesity, as well as bad nutrition.
What is the difference between a dietician and a nutritionist?
A dietitian studied dietetics, while a nutritionist studied nutrition. The two terms are often interchangeable, however they are not 100% identical.
Dietetics is the interpretation and communication of the science of nutrition so that people can make informed and practical choices about food and lifestyle, in both health and disease. Part of a dietician's course includes both hospital and community settings. The majority of dietitians work in health care, education and research, while a much smaller proportion also work in the food industry. A dietician must have a recognized degree (B.Sc. or M.Sc), or postgraduate degree in nutrition and dietetics to work as a dietician.
Nutrition is the study of nutrients in food, how the body uses nutrients, and the relationship between diet, health and disease. Major food manufacturers employ nutritionists and food scientists. Nutritionists may also work in journalism, education and research. Many nutritionists work in the field of food science and technology.
There is a lot of overlap between what nutritionists and dietitians do and studied. Some nutritionists work in health care, some dietitians work in the food industry, but a higher percentage of nutritionists work in the food industry and food science and technology, and a higher percentage of dietitians work in health care.
One could very loosely generalize and say that a nutritionist focuses firstly on a food, and then looks at its effects on people, while a dietician looks at the human, and then how that human's health is influenced by food.
If I discovered a new fruit and wanted to find out what it consisted of I would go to a nutritionist. If I found out I had a long-term disease and wanted to know whether I needed to adjust my food intake because of the disease, I would go to a dietician. Please bear in mind that this very loose comparison is both subjective and possibly too geographically bound on my part (British, National Health Service), and is simply aimed at exaggerating the differences so that lay people may see some gap between the two - differences and disagreements in my interpretation will exist in different countries, within regions of a countries, and also from college to college - and many in those areas will disagree with each other.
From what I can glean from hundreds of studies and texts that I read as an editor of a medical journal, in the USA, Australia, and to a lesser extent in the UK and the Republic of Ireland, people who call themselves dietitians are more likely to have full university bachelor's or postgraduate qualifications, while nutritionists mostly do as well, but a higher proportion may not.
According to the U.S. Bureau of Labor Statistics4, in the US, dietitians become licensed by earning the Registered Dietitian (RD) credential - administered by the Commission for Dietetic Registration and the American Dietetic Association - and are only able to use the title dietitian as described by the business and professions codes of each respective state, when they have met specific educational and work experience requirements and passed a national registration or licensure examination, respectively.
Everyone in medicine is involved in nutrition
If you ask any health care professional, be it a doctor, nurse, psychologist, or dentist to identify a part of medicine that is not at all related to nutrition, there will be a long silence as they scratch their heads.
Nutrition is present in all processes of life. Right from the very moment the sperm fertilizes an egg, through fetal development in the uterus, to the birth, human growth, maturity, old age, and eventual death. Even after death the human body serves as nutrition for other organisms. Anything that involves life and chemical or biochemical movement has nutrition at its core.
Anything that lives is dependent on energy, which results from the combustion of food.
On the next page we look at the seven major types of nutrients that the body requires. On the final page we discuss foods that protect against cancer and other diseases and nutrition in medical education.