ESSENTIALS IN COMMUNITY NUTRITION
Authors: Ivan Maleev and Nikolai Stanchev
Glossary of terms
Dieting is the practice of ingesting food in a regulated fashion to achieve or maintain a controlled weight. In most cases dieting is used in combination with physical exercise to lose weight in those who are overweight or obese. Some athletes, however, follow a diet to gain weight (usually in the form of muscle). Diets can also be used to maintain a stable body weight.
Diets to promote weight loss are generally divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie. A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2-4 kilogram weight loss in all studies. At two years, all calorie-reduced diet types cause equal weight loss irrespective of the macronutrients emphasized.
The first popular diet was "Banting", named after William Banting. In his 1863 pamphlet, "Letter on Corpulence", he outlined the details of a particular low-carbohydrate, low-calorie diet that had led to his own dramatic weight loss.
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are omnivores, each culture and each person holds some food preferences or some food taboos, due to personal tastes or due to ethical reasons. Individual dietary choices may be more or less healthful. Proper nutrition requires the proper ingestion and equally important, the absorption of vitamins, minerals, and food energy in the form of carbohydrates, proteins, and fats. Dietary habits and choices play a significant role in health and mortality, and can also define cultures and play a role in religion.
Nutrition science investigates the metabolic and physiological responses of the body to diet. With advances in the fields of molecular biology, biochemistry, and genetics, the study of nutrition is increasingly concerned with metabolism and metabolic pathways: the sequences of biochemical steps through which substances in living things change from one form to another.
Nitrogen is needed by animals to build proteins. Carnivore and herbivore diets vary in their source of nitrogen, which is a limiting nutrient for both. Herbivores consume plants to get nitrogen and carnivores consume other animals to obtain nitrogen. Nitrogen is a common element in the atmosphere but exists in a state that is not usable by most living organisms. Certain fungi and bacteria are able to convert atmospheric nitrogen into a form plants can adsorb and utilize.
The human body contains chemical compounds, such as water, carbohydrates (sugar, starch, and fiber), amino acids (in proteins), fatty acids (in lipids), and nucleic acids (DNA and RNA). These compounds in turn consist of elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium, iron, zinc, magnesium, manganese, and so on. All of these chemical compounds and elements occur in various forms and combinations (e.g. hormones, vitamins, phospholipids), both in the human body and in the plant and animal organisms that humans eat.
The human body consists of elements and compounds ingested, digested, absorbed, and circulated through the bloodstream to feed the cells of the body. Except in the unborn fetus, which receive processed nutrients from the mother, the digestive system is the first system involved in breaking down food prior to further digestion. Digestive juices, excreted into the lumen of the gastrointestinal tract, break chemical bonds in ingested molecules, and modulate their conformations and energy states. Though some molecules are absorbed into the bloodstream unchanged, digestive processes release them from the matrix of foods. Unabsorbed matter, along with some waste products of metabolism, is eliminated from the body in the feces.
Studies of nutritional status must take into account the state of the body before and after experiments, as well as the chemical composition of the whole diet and of all material excreted and eliminated from the body (in urine and feces). Comparing the food to the waste can help determine the specific compounds and elements absorbed and metabolized in the body. The effects of nutrients may only be discernible over an extended period, during which all food and waste must be analyzed. The number of variables involved in such experiments is high, making nutritional studies time-consuming and expensive, which explains why the science of human nutrition is still slowly evolving.
In general, eating a wide variety of fresh, whole (unprocessed), foods has proven favorable for one's health compared to monotonous diets based on processed foods.
In particular, the consumption of whole-plant foods slows digestion and allows better absorption, and a more favorable balance of essential nutrients per calorie, resulting in better management of cell growth, maintenance, and mitosis (cell division), as well as better regulation of appetite and blood sugar. Regularly scheduled meals (every few hours) have also proven more wholesome than infrequent or haphazard ones, although a recent study has also linked more frequent meals with a higher risk of colon cancer in men.
History of dieting (nutrition)
Humans have evolved as omnivorous hunter-gatherers over the past 250,000 years. The diet of early modern humans varied significantly depending on location and climate. The diet in the tropics tended to be based more heavily on plant foods, while the diet at higher latitudes tended more towards animal products. Analysis of postcranial and cranial remains of humans and animals from the Neolithic, along with detailed bone modification studies have shown that cannibalism was also prevalent among prehistoric humans.
Agriculture developed about 10,000 years ago in multiple locations throughout the world, providing grains such as wheat, rice, potatoes, and maize, with staples such as bread, pasta, and tortillas. Farming also provided milk and dairy products, and sharply increased the availability of meats and the diversity of vegetables. The importance of food purity was recognized when bulk storage led to infestation and contamination risks. Cooking developed as an often ritualistic activity, due to efficiency and reliability concerns requiring adherence to strict recipes and procedures, and in response to demands for food purity and consistency.
The first recorded nutritional experiment 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. But they objected, preferring vegetables and water in accordance with their Jewish dietary restrictions. The king's chief steward reluctantly agreed to a trial. Daniel and his friends received their diet for 10 days and were then compared to the king's men. Appearing healthier, they were allowed to continue with their diet.
Anaxagoras a. 475 BC, stated that food is absorbed by the human body and therefore contained "homeomerics" (generative components), suggesting the existence of nutrients. Around 400 BC, Hippocrates said, "Let food be your medicine and medicine be your food."
In the 16th century, scientist and artist Leonardo da Vinci compared metabolism to a burning candle. In 1747, Dr. James Lind, a physician in the British navy, performed the first scientific nutrition experiment, discovering that lime juice saved sailors who had been at sea for years from scurvy, a deadly and painful bleeding disorder. The discovery was ignored for forty years, after which British sailors became known as "limeys." The essential vitamin C within lime juice would not be identified by scientists until the 1930s.
Around 1770, Antoine Lavoisier, "Father of Nutrition and Chemistry", 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 fowl survival. In the early 19th century, the elements carbon, nitrogen, hydrogen and oxygen were recognized as the primary components of food, and methods to measure their proportions were developed.
In 1816, Francois Magendie discovered that dogs fed only carbohydrates and fat lost their body protein and died in a few weeks, but dogs also fed protein survived, identifying protein as an essential dietary component. In 1840, Justus Liebig discovered the chemical makeup of carbohydrates (sugars), fats (fatty acids) and proteins (amino acids.) In the 1860s, Claude Bernard discovered that body fat can be synthesized from carbohydrate and protein, showing that the energy in blood glucose can be stored as fat or as glycogen.
In the early 1880s, Kanehiro Takaki observed that Japanese sailors (whose diets consisted almost entirely of white rice) developed beriberi (or endemic neuritis, a disease causing heart problems and paralysis), but British sailors and Japanese naval officers did not. Adding various types of vegetables and meats to the diets of Japanese sailors prevented the disease.
In 1896, Eugen Baumann observed iodine in thyroid glands. In 1897, Christiaan Eijkman worked with natives of Java, who also suffered from beriberi. Eijkman observed that chickens fed the native diet of white rice developed the symptoms of beriberi, but remained healthy when fed unprocessed brown rice with the outer bran intact. Eijkman cured the natives by feeding them brown rice, discovering that food can cure disease. Over two decades later, nutritionists learned that the outer rice bran contains vitamin B1, also known as thiamine.
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. In 1906, Wilcock and Hopkins showed that the amino acid tryptophan was necessary for the survival of rats. He fed them a special mixture of food containing all the nutrients he believed were essential for survival, but the rats died. Gowland Hopkins recognized "accessory food factors" other than calories, protein and minerals, as organic materials essential to health, but which the body cannot synthesize. In 1907, Stephen M. Babcock and Edwin B. Hart conducted the single-grain experiment, which took nearly four years to complete.
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, for which he won the Nobel Prize in Chemistry in 1928. In 1928, Albert Szent-Györgyi isolated ascorbic acid, and in 1932 proved that it is vitamin C by preventing scurvy. In 1935 he synthesized it, and in 1937, he won a Nobel Prize for his efforts. Szent-Györgyi concurrently elucidated much of the citric acid cycle.
In the 1930s, William Cumming Rose identified essential amino acids, necessary protein components which the body cannot synthesize. In 1935, Underwood and Marston independently discovered the necessity of cobalt. In 1936, Eugene Floyd Dubois showed that work and school performance are related to caloric intake. In 1938, Erhard Fernholz discovered the chemical structure of vitamin E.
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. In 1941, the first Recommended Dietary Allowances (RDAs) were established by the National Research Council.
Addendum: Disciplinary dietetics in Bulgaria developed round a divide which passes through the people's revolution at end of WWII and the following socialist reconstruction of the country. None of the achievements of Prof. A. Zlatarov's "bromatology" division were retained. The latter was praised more for the socialist groups he had entertained rather than his achievements as a scholar. His direct successor in the field of nutrition, Dr. Tasho Tashev, was Gastroenterologist by profession and was personally instrumental in adopting the Soviet nutritional system, with dieting tables and regimes devised by Prof. M. I. Pevsner.
With this working plan in mind, we are far from having a picture of nutrition patterns in the Bulgarian lands. For instance, "Pavlov, I. Nutrition in the Bulgarian Lands between XV and XIX cc. Sofia, 2001" has made an attempt to describe the eating manners of the Balkan populace in the Middle Ages up to the XIX century. Since there were no food inventories in these times, Bulgarian diet is being classified as part of the Mediterranean diet, per se. Other authors on the contrary reject the notion of existing a Mediterranean race at all.
The groundbreaking advances in the fields of molecular biology, biochemistry, and genetics made the study of nutrition increasingly concerned with metabolism and metabolic pathways: the sequences of biochemical steps through which substances in living things change from one form to another. This was the meaning for Bromatology — viz., a scientific branch of organic chemistry, which was object of research in the academic career of Dr. Asen Zlatarov. His "Textbook of Bromatology" (1933) appeared after several previous revisions. It has become since a bibliographic rarity, much cited but seldom correctly analyzed reference tool. We thus classify the work and achievements of Prof. Asen Zlatarov as misnomer. Much more is necessary to elucidate on this theme in our booklist and it remains a stub, something alike colleague professor Toshko Petrov and his "Textbook of Hygiene" (1933).
On a comparative scale there was an alternative nutritional path in Bulgaria developed functionally in the years before WWII. Exemplary figure here is Dr. Vladimir Rumenov, who is presented in the booklist with the collection of essays "Nutrition and Health. Sofia, 1939" (published posthumously). Veteran colonel Vladimir Rumenov was sanitary physician in the Balkan Wars (1912-13) and First World War (1915-18). He had a formal medical education from military school in St. Petersburg and appeared subsequently in the interwar years as a natural healer, something like Petar Dimkov, but usually couldn't reach the popularity and fame of the former. Another functionary from the same cohort is Dr. Theodosi Vitanov, Member of Parliament, who published a journal in the 1930s with dietary guidelines and herbal recipes.
Thereafter in this short review we come to the book at hand. "Essentials in Community Nutrition" (1948) appeared as a result of medical congress on nutrition held in Plovdiv (1947). Later that year all legal structures of Bulgarian Medical Union were disbanded and private medical practice forbidden. Thus, Dr. Ivan Maleev, who was from the institution of General Practitioners disappeared from further attention and this book edited by him in the manner of "Manual for Family Physician" (1931) remain the last good reference volume before the sovietization principles of Prof. M. Pevsner.
Final word on the titular of the book. Our efforts to find biographical data on Ivan Maleev proved fair. He was long time next-of-kin to Prof. Asen Zlatarov, married to his sister Nedjalka. It seems Dr. Ivan Maleev was at least 10 years elder than his brother-in-law and already practicing physician from 1905 — unmistakably, evident at the time of their mutual photograph in Geneva during Zlatarov's student years there, ditto.
Picture 1: Sample illustration on the text above.
(i). Young Asen Zlatarov (Zlataroff) and Dr. Ivan Maleev in Geneva, 1905.
Copyright © 2010 by the author.