Is the selection of foods and preparation of foods, and their ingestion to be assimilated by practicing a healthy diet, many of the known health issues can be avoided. The diet of an organism is what it eats, which is largely determined by the perceived palatability of foods. Dietitians are health professionals who specialize in human nutrition, meal planning, economics, and preparation.
They are trained to provide safe, evidence-based dietary advice and management to individuals (in health and disease), as well as to institutions.Clinical nutritionists are health professionals who focus more specifically on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs. While government regulation of the use of this professional title is less universal than for “dietician”, the field is supported by many high-level academic programs, up to and including the Doctoral level, and has its own voluntary certification board, professional associations, and peer-reviewed journals, e.g. the American Society for Nutrition, Nutrition Society of India, Food Scientists and Nutritionists Association India, Indian Dietetic Association and the American Journal of Clinical Nutrition. A poor diet may have an injurious impact on health, causing deficiency diseases such as scurvy and kwashiorkor; health-threatening conditions like obesity and metabolic syndrome and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis. Nutrients A. CarbohydratesA carbohydrate is a large biological molecule, or macromolecule, consisting of carbon (C), hydrogen (H), and oxygen (O) atoms, usually with a hydrogen: oxygen atom ratio of 2:1 (as in water); in other words, with the empirical formula Cm(H2O)n (where m could be different from n).
 Some exceptions exist; for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4.  Carbohydrates are technically hydrates of carbon; structurally it is more accurate to view them as polyhydroxy aldehydes and ketenes. The term is most common in biochemistry, where it is a synonym of saccharine. The carbohydrates (saccharides) are divided into four chemical groups: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. In general, the monosaccharides and disaccharides, which are smaller (lower molecular weight) carbohydrates, are commonly referred to as sugars.  The word saccharide comes from the Greek word ???????? (sakkharon), meaning “sugar.
” While the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose.For example, grape sugar is the monosaccharide glucose, cane sugar is the disaccharide sucrose, and milk sugar is the disaccharide lactose (see illustration). Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the storage of energy (e. g. , starch and glycogen), and as structural components (e. g.
, cellulose in plants and chitin in arthropods). The 5-carbon monosaccharide ribose is an important component of coenzymes (e. g.
, ATP, FAD, and NAD) and the backbone of the genetic molecule known as RNA. The related deoxyribose is a component of DNA.Saccharides and their derivatives include many other important biomolecules that play key roles in the immune system, fertilization, preventing pathogenesis, blood clotting, and developmenti B. Fats A molecule of dietary fat typically consists of several fatty acids (containing long chains of carbon and hydrogen atoms), bonded to a glycerol. They are typically found as triglycerides (three fatty acids attached to one glycerol backbone). Fats may be classified as saturated or unsaturated depending on the detailed structure of the fatty acids involved.
Saturated fats have all of the carbon atoms in their fatty acid chains bonded to hydrogen atoms, whereas unsaturated fats have some of these carbon atoms double-bonded, so their molecules have relatively fewer hydrogen atoms than a saturated fatty acid of the same length. Unsaturated fats may be further classified as monounsaturated (one double-bond) or polyunsaturated (many double-bonds). Furthermore, depending on the location of the double-bond in the fatty acid chain, unsaturated fatty acids are classified as omega-3 or omega-6 fatty acids.Trans fats are a type of unsaturated fat with trans-isomer bonds; these are rare in nature and in foods from natural sources; they are typically created in an industrial process called (partial) hydrogenation. There are nine kilocalories in each gram of fat. Fatty acids such as conjugated i acid, catalpic acid, eleostearic acid and punicic acid, in addition to providing energy, represent potent immune modulatoryi molecules.
Saturated fats (typically from animal sources) have been a staple in many world cultures for millennia. Unsaturated fats (e. g., vegetable oil) are considered healthier, while i fats are to be avoided. Saturated and some i fats are typically solid at room temperature (such as butter or lard), while unsaturated fats are typically liquids (such as olive oil or flaxseed oil). Trans fats are very rare in nature, and have been shown to be highly detrimental to human health, but have properties useful in the food processing industry, such as rancidity resistance.  C.
Proteins Proteins are structural materials in much of the animal body (e. g. muscles, skin, and hair).
They also form the enzymes that control chemical reactions throughout the body. Each protein molecule is composed of amino acids, which are characterized by inclusion of nitrogen and sometimes sulphur (these components are responsible for the distinctive smell of burning protein, such as the keratin in hair). The body requires amino acids to produce new proteins (protein retention) and to replace damaged proteins (maintenance). As there is no protein or amino acid storage provision, amino acids must be present in the diet. Excess amino acids are discarded, typically in the urine.
For all animals, some amino acids are essential (an animal cannot produce them internally) and some are non-essential (the animal can produce them from other nitrogen-containing compounds). About twenty amino acids are found in the human body, and about ten of these are essential and, therefore, must be included in the diet. A diet that contains adequate amounts of amino acids (especially those that are essential) is particularly important in some situations: during early development and maturation, pregnancy, lactation, or injury (a burn, for instance).
A complete protein source contains all the essential amino acids; an incomplete protein source lacks one or more of the essential amino acids. It is possible with protein combinations of two incomplete protein sources (e. g. , rice and beans) to make a complete protein i and characteristic combinations are the basis of distinct cultural cooking traditions. However, complementary sources of protein do not need to be eaten at the same meal to be used together by the body.  Sources of dietary protein include meats, tofu and other soy-products, eggs, legumes, and dairy products such as milk and cheese.Excess amino acids from protein can be converted into glucose and used for fuel through a process called gluconeogenesis.
The amino acids remaining after such conversion are discarded. D. Minerals Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen that are present in nearly all organic molecules.
The term “mineral” is archaic, since the intent is to describe simply the less common elements in the diet. Some are heavier than the four just mentioned, including several metals, which often occur as ions in the body.Some dietitians recommend that these be supplied from foods in which they occur naturally, or at least as complex compounds, or sometimes even from natural inorganic sources (such as calcium carbonate from ground oyster shells). Some minerals are absorbed much more readily in the ionic forms found in such sources. On the other hand, minerals are often artificially added to the diet as supplements; the most famous is likely iodine in iodized salt which prevents goiter. E. Vitamins As with the minerals discussed above, some vitamins are recognized as essential nutrients, necessary in the diet for good health.(Vitamin D is the exception: it can be synthesized in the skin, in the presence of UVB radiation.
) Certain vitamin-like compounds that are recommended in the diet, such as carnitine, are thought useful for survival and health, but these are not “essential” dietary nutrients because the human body has some capacity to produce them from other compounds. Moreover, thousands of different photochemical have recently been discovered in food (particularly in fresh vegetables), which may have desirable properties including antioxidant activity (see below); however, experimental demonstration has been suggestive but inconclusive.Other essential nutrients that are not classified as vitamins include essential amino acids (see above), choline, essential fatty acids (see above), and the minerals discussed in the preceding section. Vitamin deficiencies may result in disease conditions, including goiter, scurvy, osteoporosis, impaired immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health (including eating disorders), among many others. Excess levels of some vitamins are also dangerous to health (notably vitamin A), and for at least one vitamin, B6, toxicity begins at levels not far above the required amount.
Deficient or excess levels of minerals can also have serious health consequences. F. Water Water is excreted from the body in multiple forms; including urine and feces, sweating, and by water vapor in the exhaled breath. Therefore it is necessary to adequately rehydrate to replace lost fluids.
Early recommendations for the quantity of water required for maintenance of good health suggested that 6–8 glasses of water daily is the minimum to maintainproper hydration.  However the notion that a person should consume eight glasses of water per day cannot be traced to a credible scientific source.  The original water intake recommendation in 1945 by the Food and Nutrition Board of the National Research Council read: “An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods. “ More recent comparisons of well-known recommendations on fluid intake have revealed large discrepancies in the volumes of water we need to consume for good health. Therefore, to help standardize guidelines, recommendations for water consumption are included in two recent European Food Safety Authority (EFSA) documents (2010): (i) Food-based dietary guidelines and (ii) Dietary reference values for water or adequate daily intakes (ADI).  These specifications were provided by calculating adequate intakes from measured intakes in populations of individuals with “desirable osmolarity values of urine and desirable water volumes per energy unit consumed. ” For healthful hydration, the current EFSA guidelines recommend total water intakes of 2.
0 L/day for adult females and 2. 5 L/day for adult males. These reference values include water from drinking water, other beverages, and from food. About 80% of our daily water requirement comes from the beverages we drink, with the remaining 20% coming from food.  Water content varies depending on the type of food consumed, with fruit and vegetables containing more than cereals, for example.
 These values are estimated using country-specific food balance sheets published by the Food and Agriculture Organisation of the United Nations. Other guidelines for nutrition also have implications for the beverages we consume for healthy hydration- for example, the World Health Organization (WHO) recommend that added sugars should represent no more than 10% of total energy intake.  The EFSA panel also determined intakes for different populations. Recommended intake volumes in the elderly are the same as for adults as despite lower energy consumption, the water requirement of this group is increased due to a reduction in renal concentrating capacityi63] Pregnant and breastfeeding women require additional fluids to stay hydrated.
The EFSA panel proposes that pregnant women should consume the same volume of water as non-pregnant women, plus an increase in proportion to the higher energy requirement, equal to 300 mL/day.  To compensate for additional fluid output, breastfeeding women require an additional 700 mL/day above the recommended intake values for non-lactating women.  For those who have healthy kidneys, it is somewhat difficult to drink too much water, but (especially in warm humid weather and while exercising) it is dangerous to drink too little.While overhydration is much less common than dehydration, it is also possible to drink far more water than necessary, which can result in water intoxication, a serious and potentially fatal condition.  In particular, large amounts of de-ionized water are dangerous.
 Basic Food Groups From 1956 until 1992 the United States Department of Agriculture recommended its “Basic Four” food groups.  These food groups were: Vegetables and fruits: Recommended as excellent sources of vitamins C and A, and a good source of fiber.A dark-green or deep-yellow vegetable or fruit was recommended every other day. Milk: Recommended as a good source of calcium, phosphorus, protein, riboflavin, and sometimes vitamins A and D. Cheese, ice cream, and ice milk could sometimes replace milk.
Meat: Recommended for protein, iron and certain B vitamins. Includes meat, poultry, fish, eggs, dry beans, dry peas, and peanut butter. Cereals and breads: Whole grain and enriched breads were especially recommended as good sources of iron, B vitamins and carbohydrates, as well as sources of protein and fiber.
Includes cereals, breads, cornmeal, macaroni, noodles, rice and spaghetti. “Other foods” were said to round out meals and satisfy appetites. These included additional servings from the Basic Four, or foods such as butter, margarine, salad dressing and cooking oil, sauces, jellies and syrups.  The Basic Four guide was omnipresent in nutrition education in the United States.  A notable example is the 1972 series Mulligan Stew, providing nutrition education for schoolchildren in reruns until 1981. Results of Malnutritionis the condition that results from eating a diet in which certain nutrients are lacking, in excess (too high in intake), or in the wrong proportions.  The verb form is “malnourish”; “malnourishment” is sometimes used instead of “malnutrition”. A number of different nutrition disorders may arise, depending on which nutrients are under- or over-abundant in the diet.
In most of the world, malnutrition is present in the form of under-nutrition, which is caused by a diet lacking adequate calories and protein—not enough food, and of poor quality.Extreme undernourishment is starvation, and its symptoms and effects are inanition. While malnutrition is more common in less-developed countries, it is also present in industrialized countries. In wealthier nations it is more likely to be caused by unhealthy diets with excess energy, fats, and refined carbohydrates. A growing trend of obesity is now a major public health concern in lower socio-economic levels and in developing countries as well.
 The World Health Organization has reported hunger and related malnutrition as the greatest single threat to the world’s public health. Improving nutrition is widely regarded as the most effective form of aid.  Nutrition-specific interventions, which address the immediate causes of undernutrition, have been proven to deliver among the best value for money of all development interventions.  Emergency measures include providing deficient micronutrients through fortified sachet powders or directly through supplements.  WHO, UNICEF, and the UN World Food Programmed recommend community management of severe acute malnutrition with ready-to-use therapeutic foods, which have been shown to cause weight gain in emergency settings. The famine relief model increasingly used by aid groups calls for giving cash or cash vouchers to the hungry to pay local farmers instead of buying food from donor countries, often required by law, to prevent dumping from hurting local farmers.
 Long term measures include fostering nutritionally dense agriculture by increasing yields, while making sure negative consequences affecting yields in the future are minimized.  Recent efforts include aid to farmers. However, World Bank strictures restrict government subsidies for farmers, while the spread of fertilizer use may adversely affect ecosystems and human health and is hampered by various civil society groups.  The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), a member of the CGIAR consortium, partners with farmers, governments, researchers and NGOs to help farmers grow nutritious crops, such as chickpea, groundnut, pigeon pea, millet and sorghum. This helps their communities have more balanceddiets and become more resilient to pests and drought. The Harnessing Opportunities for Productivity Enhancement of Sorghum and Millets in Sub-Saharan Africa and South Asia (HOPE) project, for example, is increasing yields of finger millet in Tanzania by encouraging farmers to grow improved varieties. Finger millet is very high in calcium, rich in iron and fibre, and has a better energy content than other cereals.
These characteristics make it ideal for feeding to infants and the elderly.  Malnutrition has shown to be an important concern in women, children, and the elderly.Because of pregnancies and breastfeeding, women have additional nutrient requirements.
 Children can be at risk for malnutrition even before birth, as their nutrition levels are directly tied to the nutrition of their mothers.  Breastfeeding can reduce rates of malnutrition and mortality in children, and educational programs for mothers could have a large impact on these rates.  The elderly have a large risk of malnutrition because of unique complications such as changes in appetite and energy level, and chewing and swallowing problems.Adequate elderly care is essential for preventing malnutrition, especially when the elderly cannot care for themselves.
A. Vitamin and Mineral deficiency A deficiency in iron levels can lead to anemia, which is a condition classified by decreased hemoglobin levels in the blood.  21.
4% of pre-school children have Anemia in South Africa.  Anemia is also a major cause of maternal mortality.  Approximately 50% of pregnant women in South Africa have anemia.  Anemia causes tiredness and weakness. If left untreated for long periods of time, it can damage the heart, brain, and other vital organs. Another common nutritional problem among South Africans is hypocalcemia, a deficiency in calcium. In a study of a randomly chosen rural South African community, 13.
2% of children were found to have abnormally low levels of calcium in their blood.  Additional studies done on South African children show that this deficiency can lead to Rickets.  Rickets causes weakness and pain in bones and dental structures, impaired growth, muscle cramps, and skeletal deformities.  Many South Africans also have a Thiamine (Vitamin B1) deficiency.  A serious deficiency inthis vital nutrient can cause beriberi, which has the immediate symptom of severe lethargy. If left untreated, Beriberi can cause inflammation of the nervous system and even heart failure.
Heart failure associated with beriberi is especially prominent in Johannesburg, the capital of South Africa.  Another disease common to South Africa is pellagra. Dr. D Blumhson, a physician, notes a high rate of pellagra among the patients of a hospital in Soweto, South Africa.  Pellagra seems to be especially common in patients with corn-based diets. The disease itself is caused by a Niacin deficiency. Pellagra’s symptomatology is described by the “4 D’s:”dermatitis, diarrhea, dementia, and death Pellagra causes gastrointestinal discomforts like diarrhea, nausea, vomiting, abdominal pain, and poor appetite.
 Unfortunately, this downward spiral often causes further malnutrition, which in turn further amplifies the magnitude of pellagra. An additional malnutrition problem is a deficiency in Vitamin A. It is especially prominent in the Northern Province, the KwaZulu/Natal, the Mpumalanga, the North West Province, and the Eastern Cape of South Africa. The South African Vitamin A Consultancy Group (SAVACG) conducted a national survey for the South African Department of Health that showed that one out of three children under the age of six have a Vitamin A deficiency.  Vitamin A is necessary for good vision, and a shortage of this substance can lead to visual impairments and potentially even blindness.  The World Health Organization showed that half of Vitamin A-deficient blind children die within the year, due to the detrimental effects of Vitamin A on the immune system.  Vitamin C deficiency also has detrimental effects on the South African population.Scurvy, a disease that develops from an extended shortage of Vitamin C, has previously been found prevalent in certain South African mining populations.
 This disease causes weakness, anemia, skin hemorrhages, and gum disease (gingivitis).  Because Vitamin C plays a vital role in the formation of connective tissues, a deficiency in it may also cause complications with the immune system, iron absorption, cholesterol metabolism.  B.
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health, leading to reduced lifeexpectancy and/or increased health problems.  People are considered obese when their body mass index (BMI), a measurement obtained by dividing a person’s weight by the square of the person’s height, exceeds 30 kg/m2. Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.  Obesity is most commonly caused by a combination of excessive food energy intake, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes, endocrine disorders, medications or psychiatric illness.Evidence to support the view that some obese people eat little yet gain weight due to a slow metabolism is limited.
On average obese people have a greater energy expenditure than their thin counterparts due to the energy required to maintain an increased body mass.  Dieting and physical exercise are the mainstays of treatment for obesity. Diet quality can be improved by reducing the consumption of energy-dense foods such as those high in fat and sugars, and by increasing the intake of dietary fiber.Anti-obesity drugs may be taken to reduce appetite or decrease fat absorption when used together with a suitable diet. If diet, exercise and medication are not effective, a gastric balloon may assist with weight loss, or surgery may be performed to reduce stomach volume and/or bowel length, leading to feeling full earlier and a reduced ability to absorb nutrients from food.
 Obesity is a leading preventable cause of death worldwide, with increasing rates in adults and children. Authorities view it as one of the most serious public health problems of the 21st century. Obesity is stigmatized in much of the modern world (particularly in the Western world), though it was widely seen as a symbol of wealth and fertility at other times in history, and still is in some parts of the world.  In 2013, the American Medical Association classified obesity as a disease.  History According to Walter Gratzer, the study of nutrition probably began during the 6th century BC. In China, the concept of Qi developed, a spirit or “wind” similar to what Western Europeans later called i.  Food was classified into “hot” (for example, meats, blood, ginger, and hot spices)and “cold” (green vegetables) in China, India, Malaya, and Persia.  i developed perhaps first in China alongside i.
 Ho the Physician concluded that diseases are caused by deficiencies of elements (Wu Xing: fire, water, earth, wood, and metal), and he classified diseases as well as prescribed diets.  About the same time in Italy, i of Croton (a Greek) wrote of the importance of equilibrium between what goes in and what goes out, and warned that imbalance would result disease marked by obesity or emaciation. Around 475 BC, Anaxagoras stated that food is absorbed by the human body and, therefore, contains “i” (generative components), suggesting the existence of nutrients.  Around 400 BC, Hippocrates, who recognized and was concerned with obesity, which may have been common in southern Europe at the time,  said, “Let food be your medicine and medicine be your food. “ The book that is still attributed to him, Corpus Hippocratic, called for moderation and emphasized exercise.
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