nutrition

nutrition,

study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Nutrition is achieved in various ways by different forms of life. Plants that contain the green pigment chlorophyllchlorophyll
, green pigment that gives most plants their color and enables them to carry on the process of photosynthesis. Chemically, chlorophyll has several similar forms, each containing a complex ring structure and a long hydrocarbon tail.
..... Click the link for more information. can synthesize their food from inorganic substances in the process called photosynthesisphotosynthesis
, process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g.
..... Click the link for more information. . Organisms such as plants that can thus manufacture complex organic compounds from simple inorganic nutrients are termed autotrophic. Organisms that must obtain "prefabricated" organic compounds from their environment are heterotrophic, and these include the fungi, some other plants, and animals. Heterotrophic plants may be saprophytic (obtaining nutrients from dead organisms) or parasitic (obtaining nutrients from living organisms while living on or in them). Heterotrophic animals may be parasites, herbivores (plant eaters), carnivores (meat eaters), or omnivores (obtaining nutrition from both plants and animals).

Human Nutrition

Humans require food substances to supply the components necessary to build tissues, to repair tissues as they wear out and die, to keep the body in good working condition, and to supply fuel for energy. For good nutrition a person should eat a well-balanced diet, that is, one that provides an adequate amount of each of the classes of nutrients each day, furnishing at the same time an adequate but not excessive number of calories for the body's energy needs. Children require relatively larger amounts of nutrients and calories because of their rapid growth. The foods required for proper nutrition fall roughly into three major groups: proteins, carbohydrates, and fats; vitamins, minerals, and water are also important.

Proteins

Proteinprotein,
any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellular dry weight.
..... Click the link for more information. in the diet provides amino acidsamino acid
, any one of a class of simple organic compounds containing carbon, hydrogen, oxygen, nitrogen, and in certain cases sulfur. These compounds are the building blocks of proteins.
..... Click the link for more information. for forming body proteins, including the structural proteins for building and repairing tissues, and the enzymes for carrying out the metabolic processes. In addition, protein may be used as a source of energy when the preferred fat and carbohydrate supply runs low. A body that is in the process of building itself (such as that of a growing child or an adult recovering from illness) will need a greater proportion of protein to weight than one that is fully grown and utilizes protein merely for repair of worn-out tissues. The average adult requires 1 gram of protein per kilogram of body weight per day; children may require two to three times this amount. Human proteins consist of up to 22 different amino acids, of which 9 (called essential amino acids) must be supplied by food protein; the other 13 are synthesized by human cells. Complete protein sources—those foods containing all 22 amino acids—include animal products such as meat, eggs, cheese, and milk. Incomplete protein sources, such as vegetables, beans, and grains, may be combined to create complete proteins.

Carbohydrates

Carbohydratescarbohydrate,
any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds. These compounds are produced naturally by green plants from carbon dioxide and water (see photosynthesis).
..... Click the link for more information. (starches and sugars) provide a readily available energy source. Surplus carbohydrates are also converted by the body to glycogenglycogen
, starchlike polysaccharide (see carbohydrate) that is found in the liver and muscles of humans and the higher animals and in the cells of the lower animals. Chemically it is a highly branched condensation polymer of glucose; it is readily hydrolyzed to glucose.
..... Click the link for more information. and fat, the storage forms of caloriescalorie,
abbr. cal, unit of heat energy in the metric system. The measurement of heat is called calorimetry. The calorie, or gram calorie, is the quantity of heat required to raise the temperature of 1 gram of pure water 1&degC;.
..... Click the link for more information. for energy, and to some of the amino acids used in protein synthesis. Most health professionals recommend that carbohydrates comprise 50% to 60% of the dietary calories, of which most (c.80% of all carbohydrates eaten) should be complex carbohydrates, such as cereals and vegetables. Complex carbohydrates are preferred because the fast-acting simple carbohydrates, such as honey and sugar, are difficult for the body (especially the pancreas) to handle in large doses. Simple carbohydrates also lack the vitamins, minerals, proteins, and fiberfiber, dietary,
bulky part of food that cannot be broken down by enzymes in the small intestine of the digestive system. Almost all natural fiber comes from plants. Although fiber has little nutritional value, it offers other health benefits.
..... Click the link for more information. that generally accompany foods rich in complex carbohydrates. Cereals, fruits, vegetables, legumes, and pasta are good sources of complex carbohydrates.

Fats

Fats (see fats and oilsfats and oils,
group of organic substances that form an important part of the diet and also are useful in many industries. The fats are usually solid, the oils generally liquid at ordinary room temperatures.
..... Click the link for more information. ) in the diet provide a concentrated source of energy; 1 gram of fat supplies about 9 calories as opposed to only 4 calories per gram of carbohydrates and protein. Fats in the body, in addition to acting as a source of stored energy, supply physical protection and insulation for tissues and form important portions of cell membrane structure. Fats also aid in the absorption of the fat-soluble vitamins (vitamins A, D, E, and K) from the intestine. Milk, butter, meat, and oils are important sources of fat.

Vitamins, Minerals, and Water

To keep the body functioning properly it is necessary to have, in addition to the basic foods, a sufficient intake of accessory substances such as vitaminsvitamin,
group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
..... Click the link for more information. , minerals (see mineral, dietarymineral, dietary,
any of a group of inorganic elements that are essential to humans and animals for normal body function. In nutrition, minerals are those elements for which the body's requirement is at least 100 mg per day, and trace minerals
..... Click the link for more information. ), and enough water to carry nutrients to the tissues and waste products away from them. A minimum of about 2 liters of liquid per day are recommended for the average adult. Vitamins function as coenzymescoenzyme
, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
..... Click the link for more information. in important body processes, with the exception of vitamin D, which is synthesized upon exposure to sunlight. A large variety of minerals are required, some in trace amounts and others, such as calcium and iron, in relatively large amounts. Milk, cheese, and dark, leafy green vegetables are excellent sources of calcium; liver, meat, and egg yolks are good sources of iron. Minerals are vital to the development of teeth and bones (calcium, phosphorus, and fluoride) and to the functioning of a number of the body's metabolic systems. Iron is a necessary part of hemoglobin in the blood; various metals are required in many enzymes; sodium and potassium are essential to maintenance of fluid balance and functioning of the nervous system; magnesium is needed for the normal functioning of nerves and muscles; and iodine is required for thyroid hormone. The usefulness of vitamin and mineral supplements for a person of good health who eats a well-balanced diet continues to provoke debate among health experts.

Importance of Good Nutrition

Good nutrition is reflected not only in the growth and function of the body but also in its appearance. The eyes, skin, hair, and teeth indicate whether body nourishment is good or poor. A poorly nourished child will fail to grow properly; a poorly nourished adult will have a decreased resistance to infection and disease. A diet deficient in proteins causes a disease called kwashiorkor in children; a diet deficient in both protein and calories results in marasmus, with lethargy, abdominal enlargement, and wasting—the classical malnutrition syndrome. Poor nutrition may result from excesses in the diet as well as deficiencies; excess of certain vitamins or minerals can produce potentially lethal disease states, and excess of carbohydrates or fat can result in obesity.

The Food Guide Pyramid

The U.S. Dept. of Agriculture (USDA) illustrates a well-balanced diet with the Food Guide Pyramid (1992), which emphasizes the need to eat less fat and proportionally more complex carbohydrates. At the base of the pyramid is the grains group, which should be eaten in the largest quantity (6–11 servings per day). Just above are the two groups fruits (2–4 servings) and vegetables (3–5 servings). Near the top are the meat products (2–3 servings) and dairy products (2–3 servings). At the apex are the fats, oils, and sweets, which are not considered a food group and should be consumed sparingly. See also food pyramidfood pyramid
or Food Guide Pyramid,
diagram used in nutrition education that fits food groups into a triangle and notes that, for a healthful diet, those at the base should be eaten more frequently than those at the top.
..... Click the link for more information. .

Specialized Diets

Specialized diets are useful in the treatment of certain disease states; the most common is a low-calorie diet to produce weight loss in obese persons. A diet low in phenylalaninephenylalanine
, organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein.
..... Click the link for more information. is used to treat phenylketonuriaphenylketonuria
(PKU), inherited metabolic disorder caused by a deficiency in a specific enzyme (phenylalanine hydroxylase). The absence of this enzyme, a recessive trait, prevents the body from making use of phenylalanine, one of the amino acids in most protein-rich foods, and
..... Click the link for more information. . A diet low in cholesterolcholesterol
, fatty lipid found in the body tissues and blood plasma of vertebrates; it is only sparingly soluble in water, but much more soluble in some organic solvents. A steroid, cholesterol can be found in large concentrations in the brain, spinal cord, and liver.
..... Click the link for more information. and saturated fats seems to be useful in the treatment and prevention of heart disease. Elimination of certain foods from the diet may be necessary to control allergies in some individuals. In all cases, however, specialized diets must provide all classes of essential nutrients in adequate amounts to maintain health in adults and support growth in children.

Bibliography

See J. Brody, Jane Brody's Nutrition Book (1981); S. Gershoff, The Tufts University Guide to Total Nutrition (1990); J. Mayer, Jean Mayer's Diet and Nutrition Guide (1990).

Nutrition

the process of ingesting and assimilating substances that an organism needs to meet energy requirements, to build and renew body tissues, and to regulate functions. Nutrition is an important part of metabolism. The science of nutrition deals with many problems in human physiology and in the physiology of wild and domesticated animals.

In animals. The food relationships between different animal species are the basis of the biogenous cycle of matter. They define the species’ community ties, they constitute the most important factor in population control, and they are the principal link between animals and the environment. Endogenous nutrition—feeding on food reserves in the body, for example, during famine or hibernation—is distinguished from exogenous nutrition— feeding on sustances that enter from the external environment. Food substances that are obtained by the body decompose into relatively simple chemical compounds, which after absorption are used to build tissues and organs. Nutrition is essential to the realization of all living processes, for example, muscle contraction, acclimatization to temperature and altitude changes, reproduction, and milk formation. Malnutrition lowers the body’s resistance to cold and infection and disrupts the physiology of reproduction, including the reproductive cycle, sexual arousal, and lactation; it can even lead to cessation of reproduction, as for example, in a number of rodent species. In predators, for example, the sable, ingestion of fats and lipoids is necessary to maintain reproductive capacity.

The process of nutrition is conventionally divided into four phases: food gathering, digestion, absorption, and assimilation. Nutrition is effected by various means in protozoans. Many actively ingest food through phagocytosis. Complex adaptations arise for capturing the food, for example, special systems of ciliary structures called membranelles and a mouth equipped with a threadlike apparatus. Some protozoans, mainly parasites, such as trypanosomes, live in mediums that are rich in nutrient matter and consequently feed by absorption, mainly through pinocytosis.

Nutrition determines a species’ choice of habitat and the size of the population. Animals are classified as being euryphagous —feeding on many diverse foods; stenophagous—feeding on a limited set of foods; or monophagous—feeding on only one type of food. For the most part, the fauna of tropical forests is stenophagous; to a lesser extent, so are animals that live at high latitudes.

The type of nutrition induces specific reflexes and determines the morphology of dentition, of the gastrointestinal tract, and of the sense organs. Examples of nutritionally induced reflexes are hoarding of food by certain rodents, which ensures a plentiful winter supply; the sucking reflex and the reflexive attraction to fur and warm surfaces in animals that are born blind; the reflexive brushing aside of a moving object by ungulates that are born sighted; and shaking of the nest in rooks. Except for hoarding, all these reflexes are present at birth or hatching. As the individual develops, numerous conditioned feeding reflexes are formed on the basis of the unconditioned reflexes. Nutrition is influenced by season, which affects migration, reproduction, and consequently population dynamics.

In humans. Nutrition is an external factor that substantially influences health, the ability to work, and longevity in humans. Nutritional hygiene deals with the study of the fundamentals of a sensible diet for healthy humans; dietetics studies nutrition for the ill. The science of nutrition investigates not only the requirements of a full diet but also attempts to determine the optimal conditions for synthesizing essential nutrients within the body itself.

Great emphasis is placed on investigating and evaluating nutritional conditions of populations throughout the world. Research is being conducted to increase food productivity; to create new food products, especially protein-containing foods; and to increase the nutritional value of foods by enriching with biologically active substances, for example, mineral salts and vitamins.

Nutritional deficiencies lead to disturbances of function in specific organs and systems and to cachexia, or a general weakening of the body. An adult human who performs work of average difficulty requires 3,000 kilocalories (kcal) daily (1 kcal =4.19 kilojoules). Table 1 presents the daily requirements for adult males who live in populated areas with developed community services.

Inadequate nutrition has an especially deleterious effect on children, retarding growth and physical and mental development and lowering resistance to various diseases. Vitamin deficiency produces hypovitaminoses and avitaminoses. Excessive feeding can result in many pathological conditions, including obesity, atherosclerosis, diabetes mellitus, and metabolic disturbances. Protein deficiency in the diet of children may produce the severe dystrophy kwashiorkor. The etiology of some serious diseases, for example, dysentery and food poisoning, is nutrition related.

A sound diet must meet both quality and quantity requirements.

Table 1. Value and distribution of daily caloric requirement for adult males in the USSR according to type of work¹
Type of work	Age range(years)	Caloric requirement (kcal/day)			Distribution (grams)
			Proteins		Fats		Carbohydrates
			Animal	Vegetable	Animal	Vegetable	Carbohydrates
¹The lesser metabolic intensity and body weight decrease the requirements in calories, proteins, fats, and carbohydrates for women by 15 percent. The daily caloric requirement increases 200 kcal for persons who reside in populated areas with underdeveloped community services.
Entails little or no physical exertion		2,800 2,600	38 36	58 53	63 56	27 25	382 355
Mechanized industrial, entails little physical exertion		3,000 2,800	45 42	54 50	68 64	29 27	413 385
Nonmechanized industrial, entails significant physical exertion		3,200 2,900	46 42	56 51	72 66	31 28	445 401
Nonmechanized industrial, entails moderate to great physical exertion		3,700 3,400	54 50	54 50	84 77	36 33	522 480

Table 2. Caloric content and chemical composition of some foods (per 100g)
Food	Caloric content (kcal)	Chemical composition
		Proteins (g)	Fats (9)	Carbohydrates (g)	Vitamins (mg)			Minerals (mg)
		Proteins (g)	Fats (9)	Carbohydrates (g)	A	B₁	C	Ca	K
Milk (yogurt, sour milk) .............	62	3.0	3.5	4.5	0.05	0.05	1.0	120.0	127.0
Sour cream, grade I .............	285	2.1	28.0	3.0	0.30	0.05	-	86.0	91.0
Cheese, cottage, whole............	230	11.0	19.0	3.0	-	-	-	140.0	-
Cheese, cottage, fat free..........	75	14.0	0.5	3.5	-	-	-	164.0	-
Cheese, Sovetskii .............	380	21.0	30.0	2.5	0.22	0.06	-	700.0	-
Ice cream..........................	180	3.4	9.4	18.5	-	-	-	137.0	109.0
Beef, grade I ................	154	15.0	10.0	-	0.01	0.08	-	8.0	238.0
Beef, grade II..................	106	18.0	4.0	-	-	-	-	9.0	259.0
Mutton, grade I ...................	206	14.0	16.0	-	-	0.13	-	7.0	217.0
Pork, lean....................	245	14.0	20.0	-	-	0.80	-	8.0	246.0
Pork, fatty...................	390	13.0	36.0	-	-	-	-	8.0	225.0
Ham.........................	365	14.4	33.0	-	-	0.53	-	8.0	219.0
Sausage, Liubitel’skaia .............	290	12.0	26.0	-	-	0.33	-	7.0	213.0
Sausage, Chainaia...............	150	10.0	11.0	1.0	-	-	-	7.0	213.0
Pike perch ...................	72	16.0	1.0	-	-	0.02	-	11.0	162.0
Cod .........................	65	15.0	0.5	-	-	0.04	-	31.0	198.0
Herring, Atlantic spring, salted ‖.........	120	16.0	6.0	-	Trace	0.02	-	58.0	144.0
Eggs..................	150	10.6	11.0	0.5	0.60	0.14	-	43.0	116.0
Bread, rye ..............	240	5.1	1.0	42.5	-	0.15	-	29.0	249.0
Bread, wheat.............	230	7.1	1.0	46.5	-	0.26	-	29.0	163.0
Sugar .................	390	-	-	95.5	-	-	-	-	2.0
Honey .................	320	0.3	-	78.0	-	-	2.0	5.0	35.0
Milk chocolate ............	568	5.8	37.0	47.0	-	-	-	175.0	487.0
Macaroni ...............	336	9.3	0.8	70.9	-	Trace	-	34.0	138.0
Groats, buckwheat..........	329	10.6	2.3	64.4	-	0.50	-	55.0	-
Groats, wheat ............	335	10.1	2.3	66.5	-	0.30	-	30.0	286.0
Semolina ...............	333	9.5	0.7	70.1	-	0.10	-	41.0	166.0
Rice ..................	332	6.4	0.9	72.5	-	-	-	29.0	63.0
Corn.................	340	8.4	4.3	64.9	-	0.15	-	7.0	209.0
Peas..................	310	19.6	2.2	50.8	-	0.70	3.0	63.0	906.0
Beans ................	310	19.6	2.0	51.4	-	0.53	2.9	157.0	1,061.0
Potato, autumn...........	89	1.7	-	20.0	-	0.07	7.5	8.0	426.0
Potato, spring.............	89	1.7	-	20.0	-	-	-	-	-
Butter ................	734	0.4	78.5	0.5	0.60	-	-	-	-
Butter, drawn............	869	-	93.5	-	0.60	-	-	-	-
Vegetable oil............	872	-	93.5	-	-	-	-	-	-
Cabbage, white ..........	27	1.5	-	5.2	Trace	0.05	24.0	38.0	148.0
Carrot, red .............	36	1.3	-	7.6	9.0	0.05	4.0	34.0	129.0
Scallion ...............	21	1.1	-	4.1	6.0	-	48.0	64.0	-
Onion ................	48	2.5	-	9.2	0.03	0.02	8.4	32.0	153.0
Cucumber..............	15	0.7	-	2.9	Trace	0.03	4.7	22.0	141.0
Tomato, red ............	18	0.5	-	4.0	2.0	0.05	34.0	10.0	150.0
Watermelon.............	38	0.4	-	8.8	-	0.02	3.6	3.0	33.0
Apples, Antonovka.........	48	0.3	-	11.5	-	0.02	4.9	16.0	86.0
Pears ................	44	0.3	-	10.5	Trace	0.02	3.6	17.0	193.0
Grapes ...............	70	0.3	-	16.7	-	0.05	2.7	15.0	225.0
Currants, black...........	43	0.7	-	9.8	0.7	-	294.0	35.0	365.0
Currants, red............	44	0.5	-	10.5	-	-	27.0	32.0	247.0
Strawberries, wild .........	43	1.5	-	8.9	Trace	0.02	51.0	19.0	137.0
Lemons ...............	41	0.8	-	9.2	0.4	0.02	20.0	20.0	82.0
Oranges ...............	41	0.8	-	9.2	0.3	0.06	30.0	25.0	148.0
Cherries...............	52	0.7	-	12.0	-	0.04	12.7	32.0	218.0
Plums ................	47	0.7	-	10.7	0.1	0.05	4.5	25.0	193.0
Mushrooms, cèpe .........	32	4.6	0.5	3.0	-	-	-	20.0	-
Mushooms, yellow.........	21	1.7	0.3	3.3	-	-	-	-	-
Mushrooms, honey agaric ............	23	1.7	0.5	3.8	-	-	-	-	-
Walnuts...............	612	15.0	55.4	8.3	0.01	0.22	1.3	27.0	309.0

Table 3. Value and distribution of average daily caloric intake by country
	Average daily caloric intake (kcal/inhabitant/ day)	Protein content (g/day)	Distribution among various foods (percent)
	Average daily caloric intake (kcal/inhabitant/ day)	Protein content (g/day)	Grains	Potato andother root crops	Vegetables, legumes, nuts, fruits	Sugar, sugar products	Meat, eggs	Fish	Milk, milk products
Poland ......	3,350	92.9	43.4	11.4	3.2	9.4	12.0	0.5	19.8
France ......	3,250	103.3	26.5	5.9	7.2	10.4	20.1	1.2	27.1
Australia .......	3,190	91.9	26.9	3.2	6.6	18.2	22.0	0.7	22.7
USA ........	3,160	93.8	20.3	3.5	8.9	16.3	21.0	0.7	29.2
Yugoslavia ....	3,140	91.8	58.6	3.8	6.1	8.1	7.7	0.1	15.7
Arab Republic of Egypt ......	2,940	85.1	72.6	1.0	6.4	9.2	1.9	0.7	8.5
Argentina .....	2,920	110.4	33.7	5.4	5.2	11.9	24.4	0.3	19.1
Brazil .......	2,850	71.0	38.5	12.0	16.9	15.1	7.5	0.3	9.9
Japan ......	2,350	77.6	56.5	5.6	12.6	8.4	4.0	3.5	9.3
Colombia ......	2,220	55.3	31.6	17.0	6.8	21.5	9.8	0.4	12.9
Nigeria .......	2,180	59.3	53.7	29.6	4.5	0.8	1.6	0.5	8.2
Afghanistan ...	1,950	53.3	80.0	–	2.2	7.7	3.0	–	7.3
Bolivia ........	1,860	49.3	51.1	14.5	7.2	10.4	6.7	–	9.9
India .........	1,810	45.4	68.1	2.0	10.6	9.6	0.3	0.2	9.8
Somalia .......	1,780	51.7	62.5	7.7	5.1	7.1	5.3	–	11.8

It must contain optimal ratios of the components of food, for example, essential and nonessential amino acids, polyunsaturated fatty acids, phosphatides, and sterols, as well as fats, sugars, vitamins, minerals, and organic acids. More than 60 nutritional substances must be present in the correct ratios. A sound diet provides an organism with the structural, energy, and regulatory substances that are necessary for normal functioning. Structural substances are used to build new cells and tissues and to replace old ones; they include proteins, some fats, and some minerals, for example, calcium and phosphorus. The energy food substances are carbohydrates, fats, and, to some extent, proteins. Regulatory substances, including trace elements and vitamins, participate in metabolism and perform catalytic and other regulatory functions.

A diet that excludes certain groups of foods over a long period of time disturbs the balance of food components and adversely affects the processes of assimilation and synthesis. The ideal human diet should include proteins, fats, and carbohydrates in a ratio of 1:1:4. Fifteen percent of the daily caloric intake should be accounted for by proteins, 30 percent by fats, and 55 percent by carbohydrates. At least half the amount of proteins should be of animal origin, while the fats should be 75–80 percent animal fat and 20–25 percent vegetable oil. A healthy diet must include as the principal sources of proteins and fats meat, fish, and milk products. Vegetables and fruits should also be included as the sources of carbohydrates, minerals, and vitamins (see Table 2).

Well-balanced diets are typical of the more developed countries. This applies first of all to the developed socialist countries of Europe, where the attainment of a high standard of living is one of the major goals of a planned economic policy. The general degree of food distribution is fairly high in the developed countries of Western Europe and in the USA, Canada, and Australia.

In many Asian and African countries the average daily caloric intake is less than 2,500 kcal; often, it is even less than 2,000 kcal. At the same time, the food is low in protein and fats (see Table 3). According to UN estimates, about one-half of the world’s population is underfed—in many cases, starving—and that half is concentrated in the developing countries.

Milk is the most widely consumed component of the human diet. The carbohydrates, proteins, and fats that it contains are in almost optimal proportions and are easily assimilated. However, some very populated nations, such as China, where the raising of milk-producing animals is underdeveloped, use practically no milk or milk products. The consumption of milk is also very low in India.

Daily food requirements differ in composition, depending on the climatic region (see Table 4). For example, in the European USSR the daily fat intake should be lower for inhabitants of southern regions than for inhabitants of northern regions; the proportion of protein in the diet is constant for all climatic regions. Recommended norms with respect to carbohydrates vary, being generally higher for southerners than for northerners.

Special norms that take into account the needs of a growing body have been established for children (see). Nutrition for middle-aged and older persons is recommended with the requirements of the aging body in mind. Aging is characterized by progressive atrophy and by decrease in the intensity of oxidative processes, in cellular activity, in metabolic rate, and in the functions of all systems, including the digestive system. With aging, some degree of limitation of food intake is recomended (see Table 5).

Table 4. Value and distribution of daily caloric requirement by climatic region
	Caloric requirement (kcal/day)	Distribution
		Proteins		Fats		Carbohydrates
		grams	percent	grams	percent	grams	percent
Northern ......	3,450	120	14	130	35	425	51
Central ......	3,000	105	14	95	30	410	56
Southern ......	2,850	100	15	75	25	425	61

It is important that meals be eaten at a fixed hour each day. For an adult human, four meals per day at intervals of four to five hours is optimal. Under these conditions, the strain on the digestive tract is uniform and the most complete processing of food by completely active digestive juices is ensured. Distribution of caloric intake over four meals depends on the individual’s schedule. It is recommended that breakfast provide 25 percent of the daily caloric intake; lunch 15 percent; dinner 35 percent; and supper 25 percent. For older persons or persons whose work is mental, caloric intake may be more evenly distributed, omitting large differences between the caloric value of breakfast and dinner. At present, the food service industry is an important nutritional concern.

REFERENCES

Pokrovskii, A. A. Besedy o pitanii, 2nd ed. Moscow, 1968.
Gigiena pitaniia, vols. 1–2. Edited by K. S. Petrovskii. Moscow, 1971.
Lechebnoe pitanie. Edited by I. S. Savoshchenko. Moscow, 1971.

V. A. KUDASHEVA and K. S. PETROVSKII

Nutrition

in botany, the process by which plants absorb and assimilate from the environment the chemical elements necessary for their existence. It involves the movement of matter from the environment to the cytoplasm of the plant cells and the chemical transformation of the matter into compounds characterstic

Table 5. Value and distribution of daily caloric requirement for the elderly in the USSR¹
	Age range (years)	Caloric requirement (kcal/day)	Distribution (grams)
			Proteins		Fats		Carbohydrates
			Animal	Vegetable	Animal	Vegetable	Carbohydrates
Men ....		2,350 2,200	48 45	32 30	49 46	27 25	320 300
Women ..		2,100 2,000	42 49	28 26	43 40	23 21	288 277

¹The caloric requirement increases 100–150 kcal for persons who reside in populated areas with underdeveloped community services and for persons who engage in active forms of recreation.

of the given plant species. The absorption and assimilation of nutrient matter (anabolism) together with the decomposition and excretion of the matter (catabolism) are the two components of metabolism—the basis of the life processes of an organism.

Almost all chemical elements have been found in plants. However, only the following elements are essential for plant nutrition: carbon (C), oxygen (O), hydrogen (H), nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), and iron (Fe). Essential trace elements include boron (B), manganese (Mn), zinc (Zn), copper (Cu), and molybdenum (Mo). The nutritional elements are absorbed from the air as carbon dioxide gas (CO₂) and from the soil as water (H₂o) and ions of mineral salts. In higher terrestrial plants a distinction is made between atmospheric, or leaf, nutrition (see PHOTOSYNTHESIS) and soil, or root, nutrition (seeMINERAL NUTRITION OF PLANTS). The entire surface of lower plants (bacteria, fungi, algae) absorbs CO₂, H₂O, and salts.

A plant requires different amounts of each element. Most essential in large amounts are oxygen and hydrogen, since a plant consists of 80–90 percent water. Hence, in plants the weight ratio of oxygen to hydrogen is similar to that of water, that is, 8:1. Moreover, a plant expends in transpiration hundreds of times more than its own weight in water during its lifetime (for the conversion of excess heat). The dry matter of a plant consists principally of carbon (45 percent) in combination with oxygen (42 percent), and hydrogen (6–7 percent). Mineral elements, among which nitrogen and potassium predominate, constitute only 5–7 percent of the dry matter of the plant.

No one element can be replaced by another (the principle of irreplaceability of nutritional elements). The absence or severe deficiency of any element leads to the cessation of growth and the death of the plant. Each element performs a particular function in the plant tissues, which is indissolubly related to all other functions of the organism. Thus, all organic molecules generally consist of carbon in combination with hydrogen and oxygen (see BIOGENIC ELEMENTS). Substances consisting only of these three elements (carbohydrates) are the main foods used in respiration. The membranes of plant cells also consist of polymeric carbohydrates. Each plant species or variety predominantly absorbs those elements that are essential in the largest quantities for its characteristic metabolism. For example, the potassium content in plants is usually dozens of times greater than the sodium content, although the ratio of these elements is reversed in the soil. Some plant species accumulate rare elements in their tissues. Such an element is lanthanum, and this phenomenon is used in geological exploration (see INDICATOR PLANTS).

There are several types of plant nutrition, each having a different source of carbon. Some lower plants—all fungi and most bacteria—can use carbon only from organic compounds in which it is contained in reduced form. After the plants oxidize the compounds during respiration, the chemical energy stored in the compounds is released and expended on such endergonic processes as the synthesis of more complex compounds and the movement of substances in the plant. Nutrition of this type and plants requiring.an organic source of carbon are said to be heterotrophic (see HETEROTROPHIC ORGANISMS).

Nutrition from dead organic remains is called saprophytic, and plants that feed on such remains are called saprophytes. Saprophytic nutrition characterizes all putrefactive fungi and bacteria.

Heterotrophic plants that metabolize the organic compounds of other living organisms are parasites. They include all fungi and bacteria that are causative agents of animal and plant diseases, as well as such higher plants as broom rape that feed on the juices of other plants by means of special suckers. Parasitic plant nutrition differs from symbiosis, which is characterized by a constant, mutually beneficial association between two organisms. Symbiotic plant nutrition is observed in nitrogen-fixing bacteria that settle in nodules on the roots of leguminous plants (seeNITROGEN FIXATION); in hymenomycetous fungi, whose hyphae penetrate the root tissues of woody plants (seeMYCORRHIZA); and in lichens, which consist of a group of fungi that are in permanent cohabitation with algae.

A large number of plants can assimilate carbon from carbon dioxide, reducing the gas to organic compounds. This type of nutrition, known as autotrophic nutrition (seeAUTOTROPHIC ORGANISMS), is characteristic of all higher green plants, all algae, and some bacteria. The reduction of CO₂ to organic compounds requires an expenditure of energy by means of photosynthesis or chemosynthesis.

Plant nutrition is essential to the biogeochemical cycle of matter in nature. Autotrophic plants—mainly photosynthetic autotrophs—give rise to the cycle, removing CO₂ from the atmosphere and creating organic substances that are rich in energy. Heterotrophic plants, mainly saprophytes, close the cycle by breaking down dead organic remains into the original mineral substances.

During photosynthesis, plants not only absorb matter but accumulate energy. One of the primary products of photosynthesis is sugar. When 6 gram molecules of CO₂ unite with the same quantity of H₂O, 1 gram molecule of glucose (180 g) is formed. This process occurs with the absorption of 674 kilocalories (1 kcal = 4.19 kJ) of radiant energy, which is stored in the chemical bonds of the sugar. Together with the molecules of sugar, the stored chemical energy may then be moved to other, nonphotosynthesizing plant organs, such as the root. The energy may then be released during respiration to synthesize more complex compounds and to make possible other cellular processes. Although only CO₂ and H₂o participate directly in photosynthesis, all other elements of plant nutrition, however small their quantity, are essential for the process and, especially, for the subsequent conversion of the process’s primary products.

The conversions of nutritional substances occur in various organs and tissues and are associated with one another in a continuous cycle of matter within the plant. During photosynthesis, the primary organic products (assimilates) are formed in the leaves from the CO₂ of the air and the H₂O entering from the roots. One of these assimilates—sucrose—is the universal form of carbohydrate transport. From the photosynthesizing cells of the leaves, sucrose enters a special transport system, the sieve tubes of the phloem, which ensure the descending movement of matter first through the leaf veins and then through the conducting bundles of the stem into the root. Here the assimilates leave the sieve tubes and are distributed throughout the root tissues. Water and ions of mineral salts, which first are bound by the surfaces of root cells and then permeate the cells through the cell membranes, meet the assimilates flowing in from the leaves. At the same time, some elements (potassium, sodium, calcium, magnesium) enter the sap and reach aboveground organs in an immutable state. Other elements, such as nitrogen, upon meeting the centrifugal flow of assimilates, interact with them. They become part of the composition of organic componds (amino acids and amides) and enter the sap in this changed form. A third group of elements, which includes phosphorus, upon passing through the root tissues, is also included in organic compounds (nucleotides and phosphoric esters of sugars), but the elements break off again and enter the sap mainly in the form of free ions.

One way or another, the elements of root nutrition, together with water, enter the vessels of the xylem—the second transport system of the plant. The xylem provides for the ascending movement of matter to aboveground organs. The movement of water and the dissolved elements in the vessels is due to root pressure and transpiration. In the leaf, the substances from the vessels enter the photosynthesizing cells, where the subtances’ secondary interaction with assimilates occurs. At this time, the most diverse organic and organomineral compounds are formed. After a series of complex reactions, new organs of the plant are formed from the compounds.

Plant nutrition furnishes substances and energy for the following processes: maintenance of vital activity (replacement of nutrient loss during respiration and excretion to the environment), growth of organs, deposit of matter for storage, and reproduction (formation of fruits and seeds).

When plants receive inadequate amounts of nutrient substances, the processes of vital activity and reproduction are the first to receive nutrients. If the deficiency is moderate, the growth of young parts of the plant (upper leaves, root tips) still continues by means of reutilization, that is, the repeated use of nutritive elements by means of their effluence from older leaves. With severe nutrient deficiency, growth ceases and all nutrient resources are directed to the principal function of a plant organism —reproduction. Nutrient-deficient barley, for example, grows only to a height of 4–5 cm but forms two or three normal caryopses. An excess of any one nutritive element is as harmful as a deficiency.

The most effective means of maintaining the yield of agricultural plants is the creation of the best conditions of soil nutrition through the use of irrigation and fertilization. In hotbeds and hothouses, the atmospheric nutrition of plants may be regulated by changing the CO₂ content of the air and by using supplementary lighting. The creation of the optimal set of conditions for plant nutrition is one of the principal goals of horticulture. Also important is the implementation of measures for reclaiming saline soils (removal of excess salts, which are harmful to plant nutrition) and agrotechnical measures of improving the soil (compacting and aeration). Weeds, which compete with crops for nutrients, must be controlled.

REFERENCES

Timiriazev, K. A. Zhizn’ rastenii (collection of articles), vol. 3. Moscow, 1949.
Sabinin, D. A. Fiziologicheskie osnovy pitaniia rastenii. Moscow, 1965.
Maksimov, N. A. Kak zhivet rastenie, 4th ed. [Moscow, 1966.]

D. B. VAKHMISTROV

nutrition

[nü′trish·ən] (biology) The science of nourishment, including the study of nutrients that each organism must obtain from its environment in order to maintain life and reproduce.

nutrition

1. a process in animals and plants involving the intake of nutrient materials and their subsequent assimilation into the tissues 2. the study of nutrition, esp in humans
www.crnusa.org

nutrition

Nutrition

Definition

Good nutrition can help prevent disease and promote health. There are six categories of nutrients that the body needs to acquire from food: protein, carbohydrates, fat, fibers, vitamins and minerals, and water.

Proteins

Protein supplies amino acids to build and maintain healthy body tissue. There are 20 amino acids considered essential because the body must have all of them in the right amounts to function properly. Twelve of these are manufactured in the body but the other eight amino acids must be provided by the diet. Foods from animal sources such as milk or eggs often contain all these essential amino acids while a variety of plant products must be taken together to provide all these necessary protein components.

Fat

Fat supplies energy and transports nutrients. There are two families of fatty acids considered essential for the body: the omega-3 and omega-6 fatty acids. Essential fatty acids are required by the body to function normally. They can be obtained from canola oil, flaxseed oil, cold-water fish, or fish oil, all of which contain omega-3 fatty acids, and primrose or black currant seed oil, which contains omega-6 fatty acids. The American diet often contains an excess of omega-6 fatty acids and insufficient amounts of omega-3 fats. Increased consumption of omega-3 oils is recommended to help reduce risk of cardiovascular diseases and cancer and alleviate symptoms of rheumatoid arthritis, premenstrual syndrome, dermatitis, and inflammatory bowel disease.

Carbohydrates

Carbohydrates are the body's main source of energy and should be the major part of total daily intake. There are two types of carbohydrates: simple carbohydrates (such as sugar or honey) or complex carbohydrates (such as grains, beans, peas, or potatoes). Complex carbohydrates are preferred because these foods are more nutritious yet have fewer calories per gram compared to fat and cause fewer problems with overeating than fat or sugar. Complex carbohydrates also are preferred over simple carbohydrates by diabetics because they allow better blood glucose control.

Fiber

Fiber is the material that gives plants texture and support. Although it is primarily made up of carbohydrates, it does not have a lot of calories and is usually not broken down by the body for energy. Dietary fiber is found in plant foods such as fruits, vegetables, legumes, nuts, and whole grains.There are two types of fiber: soluble and insoluble. Insoluble fiber, as the name implies, does not dissolve in water because it contains high amount of cellulose. Insoluble fiber can be found in the bran of grains, the pulp of fruit and the skin of vegetables. Soluble fiber is the type of fiber that dissolves in water. It can be found in a variety of fruits and vegetables such as apples, oatmeal and oat bran, rye flour, and dried beans.Although they share some common characteristics such as being partially digested in the stomach and intestines and have few calories, each type of fiber has its own specific health benefits. Insoluble fiber speeds up the transit of foods through the digestive system and adds bulk to the stools, therefore, it is the type of fiber that helps treat constipation or diarrhea and prevents colon cancer. On the other hand, only soluble fiber can lower blood cholesterol levels. This type of fiber works by attaching itself to the cholesterol so that it can be eliminated from the body. This prevents cholesterol from recirculating and being reabsorbed into the bloodstream. In 2003, the World Health Organization released a new report specifically outlining the link of a healthy diet rich in high-fiber plant foods to preventing cancer.

Vitamins and minerals

Vitamins are organic substances present in food and required by the body in a small amount for regulation of metabolism and maintenance of normal growth and functioning. The most commonly known vitamins are A, B₁ (thiamine), B₂ (riboflavin), B₃ (niacin), B₅ (pantothenic acid), B₆ (pyridoxine), B₇ (biotin), B₉ (folic acid), B₁₂ (cobalamin), C (ascorbic acid), D, E, and K. The B and C vitamins are watersoluble, excess amounts of which are excreted in the urine. The A, D, E, and K vitamins are fat-soluble and will be stored in the body fat.Minerals are vital to our existence because they are the building blocks that make up muscles, tissues, and bones. They also are important components of many life-supporting systems, such as hormones, oxygen transport, and enzyme systems.There are two kinds of minerals: the major (or macro) minerals and the trace minerals. Major minerals are the minerals that the body needs in large amounts. The following minerals are classified as major: calcium, phosphorus, magnesium, sodium, potassium, sulfur, and chloride. They are needed to build muscles, blood, nerve cells, teeth, and bones. They also are essential electrolytes that the body requires to regulate blood volume and acid-base balance.Unlike the major minerals, trace minerals are needed only in tiny amounts. Even though they can be found in the body in exceedingly small amounts, they are also very important to the human body. These minerals participate in most chemical reactions in the body. They also are needed to manufacture important hormones. The following are classified as trace minerals: iron, zinc, iodine, copper, manganese, fluoride, chromium, selenium, molybdenum, and boron.Many vitamins (such as vitamins A, C, and E) and minerals (such as zinc, copper, selenium, or manganese) act as antioxidants. They protect the body against the damaging effects of free radicals. They scavenge or mop up these highly reactive radicals and change them into inactive, less harmful compounds. In so doing, these essential nutrients help prevent cancer and many other degenerative diseases, such as premature aging, heart disease, autoimmune diseases, arthritis, cataracts, Alzheimer's disease, and diabetes mellitus.

Water

Water helps to regulate body temperature, transports nutrients to cells, and rids the body of waste materials.

Origins

Unlike plants, human beings cannot manufacture most of the nutrients that they need to function. They must eat plants and/or other animals. Although nutritional therapy came to the forefront of the public's awareness in the late twentieth century, the notion that food affects health is not new. John Harvey Kellogg was an early health-food pioneer and an advocate of a high-fiber diet. An avowed vegetarian, he believed that meat products were particularly detrimental to the colon. In the 1870s, Kellogg founded the Battle Creek Sanitarium, where he developed a diet based on nut and vegetable products.

Purpose

Good nutrition helps individuals achieve general health and well-being. In addition, dietary modifications might be prescribed for a variety of complaints including allergies, anemia, arthritis, colds, depressions, fatigue, gastrointestinal disorders, high or low blood pressure, insomnia, headaches, obesity, pregnancy, premenstrual syndrome (PMS), respiratory conditions, and stress.Nutritional therapy may also be involved as a complement to the allopathic treatments of cancer, diabetes, and Parkinson's disease. Other specific dietary measures include the elimination of food additives for attention deficit hyperactivity disorder (ADHD), gluten-free diets for schizophrenia, and dairy-free for chronic respiratory diseases.A high-fiber diet helps prevent or treat the following health conditions:

High cholesterol levels. Fiber effectively lowers blood cholesterol levels. It appears that soluble fiber binds to cholesterol and moves it down the digestive tract so that it can be excreted from the body. This prevents the cholesterol from being reabsorbed into the bloodstream.
Constipation. A high-fiber diet is the preferred nondrug treatment for constipation. Fiber in the diet adds more bulk to the stools, making them softer and shortening the time foods stay in the digestive tract.
Hemorrhoids. Fiber in the diet adds more bulk and softens the stool, thus, reducing painful hemorrhoidal symptoms.
Diabetes. Soluble fiber in the diet slows down the rise of blood sugar levels following a meal and helps control diabetes.
Obesity. Dietary fiber makes a person feel full faster.
Cancer. Insoluble fiber in the diet speeds up the movement of the stools through the gastrointestinal tract. The faster food travels through the digestive tract, the less time there is for potential cancer-causing substances to work. Therefore, diets high in insoluble fiber help prevent the accumulation of toxic substances that cause cancer of the colon. Because fiber reduces fat absorption in the digestive tract, it also may prevent breast cancer.

A diet low in fat also promotes good health and prevents many diseases. Low-fat diets can help treat or control the following conditions:

Obesity. High fat consumption often leads to excess caloric and fat intake, which increases body fat.
Coronary artery disease. High consumption of saturated fats is associated with coronary artery disease.
Diabetes. People who are overweight tend to develop or worsen existing diabetic conditions due to decreased insulin sensitivity.
Breast cancer. A high dietary consumption of fat is associated with an increased risk of breast cancer.

Description

The four basic food groups, as outlined by the United States Department of Agriculture (USDA) are:

dairy products (such as milk and cheese)
meat and eggs (such as fish, poultry, pork, beef, and eggs)
grains (such as bread cereals, rice, and pasta)
fruits and vegetables

The USDA recommendation for adults is that consumption of meat, eggs, and dairy products should not exceed 20% of total daily caloric intake. The rest (80%) should be devoted to vegetables, fruits, and grains. For children age two or older, 55% of their caloric intake should be in the form of carbohydrates, 30% from fat, and 15% from proteins. In addition, saturated fat intake should not exceed 10% of total caloric intake. This low-fat, high-fiber diet is believed to promote health and help prevent many diseases, including heart disease, obesity, and cancer.Allergenic and highly processed foods should be avoided. Highly processed foods do not contain significant amounts of essential trace minerals. Furthermore, they contain lots of fat and sugar as well as preservatives, artificial sweeteners and other additives. High consumption of these foods causes build up of unwanted chemicals in the body and should be avoided. Food allergies causes a variety of symptoms including food cravings, weight gain, bloating, and water retention. They also may worsen chronic inflammatory conditions such as arthritis.

Preparations

An enormous body of research exists in the field of nutrition. Mainstream Western medical practitioners point to studies that show that a balanced diet, based on the USDA Food Guide Pyramid, provides all of the necessary nutrients.In 2004, the USDA was working on a revision of the Food Guide Pyramid to reflect changes in American lifestyle habits. The new eating guide was due for release in January 2005. The World Health Organization (WHO) also was weighing in on the obesity and nutrition issue, even struggling with objections from member nations that supply goods such as sugar, to endorse a global strategy in spring 2004 on diet, physical activity and health.The Food Guide Pyramid recommends the following daily servings in six categories:

grains: six or more servings
vegetables: five servings
fruits: two to four servings
meat: two to three servings
dairy: two to three servings
fats and oils: use sparingly

Precautions

Individuals should not change their diets without the advice of nutritional experts or health care professionals. Certain individuals, especially children, pregnant and lactating women, and chronically ill patients, only should change their diets under professional supervision.

Side effects

It is best to obtain vitamins and minerals through food sources. Excessive intake of vitamins and mineral supplements can cause serious health problems. Likewise, eating too much of one type of food, as can happen with fad diets, can be harmful. The key to nutrition is moderation. If a person feels they are short on iron, for example, he or she should not go too far to the extreme in getting more iron through diet and supplements. A 2003 report said that too much stored iron in the body has possibly been linked with heart disease, cancer and diabetes.The following is a list of possible side effects resulting from excessive doses of vitamins and minerals:

vitamin A: birth defects, irreversible bone and liver damage
vitamin B₁: deficiencies in B₂ and B₆
vitamin B₆: damage to the nervous system
vitamin C: affects the absorption of copper; diarrhea
vitamin D: hypercalcemia (abnormally high concentration of calcium in the blood)
phosphorus: affects the absorption of calcium
zinc: affects absorption of copper and iron; suppresses the immune system

Research and general acceptance

Due to a large volume of scientific evidence demonstrating the benefits of the low-fat, high-fiber diet in disease prevention and treatment, these recommendations have been accepted and advocated by both complementary and allopathic practitioners.

Resources

Books

U.S. Preventive Services Task Force Guidelines. "Counseling to Promote a Healthy Diet." Guide to Clinical Preventive Services. 2nd ed. 〈http://cpmcnet.-columbia.edu/texts/gcps/gcps0066.html〉.

Periodicals

Clapp, Stephen. "World Health Assembly Adopts Global Anti-obesity Strategy." Food Chemical News May 31, 2004: 26.Halbert, Steven C. "Diet and Nutrtion in Primary Care: From Antioxidants to Zinc." Primary Care: Clinics in Office Practice December 1997: 825-843.Mangels, Reed. "How Can You Avoid Having Too Much Iron?" Vegetarian Journal March-April 2003: 17.Turner, Lisa. "Good 'n Plenty." Vegetarian Times February 1999: 48."U.N. Report Supports Key Role for Diet, Activity in Cancer Prevention." Cancer Weekly March 25, 2003: 154.Vickers, Andrew, and Catherine Zollman. "Unconventional approaches to nutritional medicine." British Medical Journal November 27, 1999: 1419.

Organizations

American Association of Nutritional Consultants. 810 S. Buffalo Street, Warsaw, IN 46580. (888) 828-2262.American Dietetic Association. 216 W. Jackson boulevard, Suite 800, Chicago, IL 60606-6995. (800) 366-1655. http://www.eatright.org.

nu·trit·ion

(nū-trish'ŭn), 1. A function of living plants and animals, consisting of the ingestion and metabolism of food material whereby tissue is built up and energy liberated. Synonym(s): trophism (2) 2. The study of the food and liquid requirements of human beings or animals for normal physiologic function, including energy, need, maintenance, growth, activity, reproduction, and lactation. [L. nutritio, fr. nutrio, to nourish]

nutrition

(no͞o-trĭsh′ən, nyo͞o-)n.1. The process of nourishing or being nourished, especially the process by which a living organism assimilates food and uses it for growth and for replacement of tissues.2. The science or study that deals with food and nourishment, especially in humans.3. A source of nourishment; food.

nu·tri′tion·al adj.nu·tri′tion·al·ly adv.

nutrition

The study of the metabolic utilisation of foods.

nutrition

The study of the metabolic utilization of foods. See Applied nutrition, Malnutrition, Parenteral nutrition, Total parenteral nutrition.

nu·tri·tion

(nū-trish'ŭn) 1. A function of living plants and animals, consisting in the taking in and metabolism of food material whereby tissue is built up and energy liberated. 2. The study of the food and liquid requirements of human beings or animals for normal physiologic function, including energy, maintenance, growth, activity, reproduction, and lactation. [L. nutritio, fr. nutrio, to nourish]

nutrition

1. The process by which substances external to the body are assimilated and restructured to form part of the body or are consumed as a source or energy. 2. The study of the dietary requirements of the body and of the amounts of water, carbohydrates, fats, proteins, vitamins, minerals and fibre needed for the maintenance of health.

nutrition

the process of promoting the continued existence and growth of living organisms by taking in materials from the environment. Different organisms have different nutritional requirements. For example, the bacterium E. coli is capable of synthesizing all the necessary AMINO ACIDS, COENZYMES, PORPHYRIN structures (e.g. in HAEMOGLOBIN) and NUCLEIC ACIDS, whereas humans need to take in amino acids, VITAMINS, CARBOHYDRATES and FATTY ACIDS, in addition to water and many ESSENTIAL ELEMENTS.

nu·tri·tion

(nū-trish'ŭn) 1. Function of living plants and animals, consisting of ingestion and metabolism of food material whereby tissue is built up and energy liberated. 2. Study of dietary requirements of human beings or animals for normal physiologic function. [L. nutritio, fr. nutrio, to nourish]

Patient discussion about nutrition

Q. How do I now if my nutrition is correct? I guess it's not... and Id like to fix it but dont really know what should I change...A. Read more about the recommended nutrition, and learn how to analyze yours here (www.nlm.nih.gov/medlineplus/nutrition.html), and if you have further concerns, you may want to consult a professional (e.g. dietitian). In general, nutrition should include about 30-35 calories per kg per day.
Eat a healthy diet with a lot of vegetables, fruits, and whole grains and a limited amount of red meat. Get at least five servings of fruits and vegetables every day. More is even better. Tips for achieving this goal include: Make fruits and vegetables part of every meal. Frozen or canned can be used when fresh isn't convenient. Put fruit on your cereal. Eat vegetables as snacks. Have a bowl of fruit out all the time for kids to take snacks from.
Cut down on bad fats (trans fatty acids and saturated fats) and consume good fats (polyunsaturated and monounsaturated fat like olive oil and canola oil). Tips for achieving this goal include: Choose chicken, fish, or beans instead of red meat and ch

Q. Will it be good and what is its nutritional value? I wish to take oats as my breakfast with milk or juice. Will it be good and what is its nutritional value?A. It is undoubtedly a good idea to have oats as your breakfast with milk or juice. It is well known for its high fiber content which is the best remedy for constipation and also plays a vital role in the cholesterol management and smoothens the digestive process. It also helps you in loosing body weight. It is even good for nervous system and in turn treats depression as well. Around 150gm of oat gives 600kcal energy. Apart from protein, lipid, carbohydrate and fiber content, it is a very good source of minerals such as calcium, iron sodium, zinc, and vitamins like vitamin C, B, A.

Q. What is the nutritional value of oats? I am having oats for my morning breakfast from last week, as I know it is good to have them. But what is the nutritional value of oats?A. oats are rich with vitamins, energy and protein. makes a wonderful breakfast! (at least when my wife makes it!!).
here's a link to a nutritional value list of oats:
http://www.healthrecipes.com/oats.htm
and here's a link to some recipes!:
bread - http://momsrecipesandmore.blogspot.com/2008/12/toasted-oatmeal-bread.html
Biscuits - http://www.vegan-food.net/recipe/927/Oatmeal-Raisin-Cookies/
oatmeal- http://www.fatfree.com/recipes/breakfast/oatmeal
bon apetite!

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Proteins

Carbohydrates

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Specialized Diets

Bibliography

Nutrition

REFERENCES

Nutrition

REFERENCES

nutrition

nutrition

nutrition

Nutrition

Definition

Proteins

Fat

Carbohydrates

Fiber

Vitamins and minerals

Water

Origins

Purpose

Description

Preparations

Precautions

Side effects

Research and general acceptance

Resources

Books

Periodicals

Organizations

nu·trit·ion

nutrition

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Patient discussion about nutrition

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noun food

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noun something fit to be eaten

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noun (physiology) the organic process of nourishing or being nourished

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noun the scientific study of food and drink (especially in humans)

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