Hart started the cow feeding, single-grain experiment , which took nearly four years to complete. The term "mineral" is archaic, since the intent is to describe simply the less common elements in the diet. Worldwide prevalence of anemia — The main fuel used by the body during exercise is carbohydrates, which is stored in muscle as glycogen — a form of sugar. Views Read Edit View history.
An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins, which is one reason why a balance between omega-3 and omega-6 is believed important for cardiovascular health.
In industrialized societies, people typically consume large amounts of processed vegetable oils, which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids. Moreover, the conversion desaturation of DGLA to AA is controlled by the enzyme deltadesaturase , which in turn is controlled by hormones such as insulin up-regulation and glucagon down-regulation.
The amount and type of carbohydrates consumed, along with some types of amino acid, can influence processes involving insulin, glucagon, and other hormones; therefore, the ratio of omega-3 versus omega-6 has wide effects on general health, and specific effects on immune function and inflammation , and mitosis i.
Proteins are structural materials in much of the animal body e. 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: 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. However, complementary sources of protein do not need to be eaten at the same meal to be used together by the body.
Water is excreted from the body in multiple forms; including urine and feces , sweating , and by water vapour 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 maintain proper hydration. Most of this quantity is contained in prepared foods. For healthful hydration, the current EFSA guidelines recommend total water intakes of 2.
These reference values include water from drinking water, other beverages, and from food. 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 capacity.
Dehydration and over-hydration - too little and too much water, respectively - can have harmful consequences. Drinking too much water is one of the possible causes of hyponatremia , i.
Pure ethanol provides 7 calories per gram. For distilled spirits , a standard serving in the United States is 1. A 5 ounce serving of wine contains to calories. A 12 ounce serving of beer contains 95 to calories. Alcoholic beverages are considered empty calorie foods because other than calories, these contribute no essential nutrients. The micronutrients are minerals , vitamins , and others.
Dietary minerals are inorganic 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. Many elements are essential in relative quantity; they are usually called "bulk minerals".
Some are structural, but many play a role as electrolytes. Many elements are required in trace amounts, usually because they play a catalytic role in enzymes.
Vitamins are essential nutrients,  necessary in the diet for good health. Vitamin D is an exception, as it can be synthesized in the skin in the presence of UVB radiation , and many animal species can synthesize vitamin C.
Vitamin deficiencies may result in disease conditions, including goitre , scurvy , osteoporosis , impaired immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health , among many others. Phytochemicals such as polyphenols are compounds produced naturally in plants phyto means "plant" in Greek. In general, the term is used to refer to compounds which do not appear to be nutritionally essential and yet may have positive impacts on health.
To date, there is no conclusive evidence in humans that polyphenols or other non-nutrient compounds from plants have health benefit effects. While initial studies sought to reveal if nutrient antioxidant supplements might promote health, one meta-analysis concluded that supplementation with vitamins A and E and beta-carotene did not convey any benefits and may in fact increase risk of death.
Vitamin C and selenium supplements did not impact mortality rate. Health effects of non-nutrient phytochemicals such as polyphenols were not assessed in this review. Animal intestines contain a large population of gut flora. In humans, the four dominant phyla are Firmicutes , Bacteroidetes , Actinobacteria , and Proteobacteria.
Bacteria in the large intestine perform many important functions for humans, including breaking down and aiding in the absorption of fermentable fiber, stimulating cell growth, repressing the growth of harmful bacteria, training the immune system to respond only to pathogens, producing vitamin B 12 , and defending against some infectious diseases.
There is not yet a scientific consensus as to health benefits accruing from probiotics or prebiotics. Carnivore and herbivore diets are contrasting, with basic nitrogen and carbon proportions vary for their particular foods. Many herbivores rely on bacterial fermentation to create digestible nutrients from indigestible plant cellulose, while obligate carnivores must eat animal meats to obtain certain vitamins or nutrients their bodies cannot otherwise synthesize. Plant nutrition is the study of the chemical elements that are necessary for plant growth.
Some elements are directly involved in plant metabolism. However, this principle does not account for the so-called beneficial elements, whose presence, while not required, has clear positive effects on plant growth.
A nutrient that is able to limit plant growth according to Liebig's law of the minimum is considered an essential plant nutrient if the plant cannot complete its full life cycle without it. There are 16 essential plant soil nutrients, besides the three major elemental nutrients carbon and oxygen that are obtained by photosynthetic plants from carbon dioxide in air, and hydrogen , which is obtained from water.
Plants uptake essential elements from the soil through their roots and from the air consisting of mainly nitrogen and oxygen through their leaves. Green plants obtain their carbohydrate supply from the carbon dioxide in the air by the process of photosynthesis.
Carbon and oxygen are absorbed from the air, while other nutrients are absorbed from the soil. These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root. In the leaves, stomata open to take in carbon dioxide and expel oxygen. The carbon dioxide molecules are used as the carbon source in photosynthesis. Although nitrogen is plentiful in the Earth's atmosphere, very few plants can use this directly.
Most plants, therefore, require nitrogen compounds to be present in the soil in which they grow. This is made possible by the fact that largely inert atmospheric nitrogen is changed in a nitrogen fixation process to biologically usable forms in the soil by bacteria.
Plant nutrition is a difficult subject to understand completely, partially because of the variation between different plants and even between different species or individuals of a given clone. Elements present at low levels may cause deficiency symptoms, and toxicity is possible at levels that are too high.
Furthermore, deficiency of one element may present as symptoms of toxicity from another element, and vice versa. Canada's Food Guide is an example of a government-run nutrition program.
Produced by Health Canada , the guide advises food quantities, provides education on balanced nutrition, and promotes physical activity in accordance with government-mandated nutrient needs. Like other nutrition programs around the world, Canada's Food Guide divides nutrition into four main food groups: Dietary and physical activity guidelines from the USDA are presented in the concept of MyPlate , which superseded the food pyramid , which replaced the Four Food Groups.
Department of Health and Human Services provides a sample week-long menu that fulfills the nutritional recommendations of the government. Governmental organisations have been working on nutrition literacy interventions in non-primary health care settings to address the nutrition information problem in the U. The FNP has developed a series of tools to help families participating in the Food Stamp Program stretch their food dollar and form healthful eating habits including nutrition education.
It is designed to assist limited-resource audiences in acquiring the knowledge, skills, attitudes, and changed behavior necessary for nutritionally sound diets, and to contribute to their personal development and the improvement of the total family diet and nutritional well-being. Launched in , this program promotes lifelong healthful eating patterns and physically active lifestyles for children and their families.
It is an interactive educational program designed to help prevent childhood obesity through classroom activities that teach children healthful eating habits and physical exercise. Nutrition is taught in schools in many countries. In England and Wales , the Personal and Social Education and Food Technology curricula include nutrition, stressing the importance of a balanced diet and teaching how to read nutrition labels on packaging. In many schools, a Nutrition class will fall within the Family and Consumer Science or Health departments.
In some American schools, students are required to take a certain number of FCS or Health related classes. Nutrition is offered at many schools, and, if it is not a class of its own, nutrition is included in other FCS or Health classes such as: In many Nutrition classes, students learn about the food groups, the food pyramid, Daily Recommended Allowances, calories, vitamins, minerals, malnutrition, physical activity, healthful food choices, portion sizes, and how to live a healthy life.
In the US, Registered dietitian nutritionists RDs or RDNs  are health professionals qualified to provide safe, evidence-based dietary advice which includes a review of what is eaten, a thorough review of nutritional health, and a personalized nutritional treatment plan.
They also provide preventive and therapeutic programs at work places, schools and similar institutions. Certified Clinical Nutritionists or CCNs, are trained health professionals who also offer dietary advice on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs. These Board Certified Nutritionists typically specialize in obesity and chronic disease.
In order to become board certified, potential CNS candidate must pass an examination, much like Registered Dieticians. This exam covers specific domains within the health sphere including; Clinical Intervention and Human Health. The study found that health literacy increases with education and people living below the level of poverty have lower health literacy than those above it.
Another study examining the health and nutrition literacy status of residents of the lower Mississippi Delta found that 52 percent of participants had a high likelihood of limited literacy skills. For example, only 12 percent of study participants identified the My Pyramid graphic two years after it had been launched by the USDA. The study also found significant relationships between nutrition literacy and income level and nutrition literacy and educational attainment  further delineating priorities for the region.
Among these problems are the lack of information about food choices, a lack of understanding of nutritional information and its application to individual circumstances, limited or difficult access to healthful foods, and a range of cultural influences and socioeconomic constraints such as low levels of education and high levels of poverty that decrease opportunities for healthful eating and living.
The links between low health literacy and poor health outcomes has been widely documented  and there is evidence that some interventions to improve health literacy have produced successful results in the primary care setting. More must be done to further our understanding of nutrition literacy specific interventions in non-primary care settings  in order to achieve better health outcomes.
Malnutrition refers to insufficient, excessive, or imbalanced consumption of nutrients by an organism. In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption.
In developing countries, malnutrition is more likely to be caused by poor access to a range of nutritious foods or inadequate knowledge. The aim was to boost nutrition and livelihoods by producing a product that women could make and sell, and which would be accepted by the local community because of its local heritage.
Although under- and over-nutrition are often viewed as human problems, pet animals can be under- or overfed by their owners, domesticated animals can be undernourished for macro- and micro-nutrients, affecting growth and health, and wild animals can be undernourished to the point of starvation and death.
Nutritionism is the view that excessive reliance on food science and the study of nutrition can lead to poor nutrition and to ill health. It was originally credited to Gyorgy Scrinis ,  and was popularized by Michael Pollan. Since nutrients are invisible, policy makers rely on nutrition experts to advise on food choices.
Because science has an incomplete understanding of how food affects the human body, Pollan argues, nutritionism can be blamed for many of the health problems relating to diet in the Western World today.
ULs are set a safe fraction below amounts shown to cause health problems. ULs are part of Dietary Reference Intakes. When too much of one or more nutrients is present in the diet to the exclusion of the proper amount of other nutrients, the diet is said to be unbalanced.
High calorie food ingredients such as vegetable oils, sugar and alcohol are referred to as "empty calories" because they displace from the diet foods that also contain protein, vitamins, minerals and fiber. Research indicates that improving the awareness of nutritious meal choices and establishing long-term habits of healthy eating have a positive effect on cognitive and spatial memory capacity, with potential to increase a student's ability to process and retain academic information.
Some organizations have begun working with teachers, policymakers, and managed foodservice contractors to mandate improved nutritional content and increased nutritional resources in school cafeterias from primary to university level institutions.
Health and nutrition have been proven to have close links with overall educational success. There is limited research available that directly links a student's Grade Point Average G. Additional substantive data is needed to prove that overall intellectual health is closely linked to a person's diet, rather than just another correlation fallacy.
Nutritional supplement treatment may be appropriate for major depression , bipolar disorder , schizophrenia , and obsessive compulsive disorder , the four most common mental disorders in developed countries. Cancer is now common in developing countries. According to a study by the International Agency for Research on Cancer , "In the developing world, cancers of the liver, stomach and esophagus were more common, often linked to consumption of carcinogenic preserved foods, such as smoked or salted food, and parasitic infections that attack organs.
Several lines of evidence indicate lifestyle-induced hyperinsulinemia and reduced insulin function i.
For example, hyperinsulinemia and insulin resistance are strongly linked to chronic inflammation, which in turn is strongly linked to a variety of adverse developments such as arterial microtrauma and clot formation i. Hyperinsulinemia and insulin resistance the so-called metabolic syndrome are characterized by a combination of abdominal obesity , elevated blood sugar , elevated blood pressure , elevated blood triglycerides , and reduced HDL cholesterol. The state of obesity clearly contributes to insulin resistance, which in turn can cause type 2 diabetes.
Virtually all obese and most type 2 diabetic individuals have marked insulin resistance. Although the association between overweight and insulin resistance is clear, the exact likely multifarious causes of insulin resistance remain less clear.
It has been demonstrated that appropriate exercise, more regular food intake, and reducing glycemic load see below all can reverse insulin resistance in overweight individuals and thereby lower their blood sugar level , in those with type 2 diabetes. In addition, reduced leptin signaling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
In any case, analogous to the way modern man-made pollution may possess the potential to overwhelm the environment's ability to maintain homeostasis , the recent explosive introduction of high glycemic index and processed foods into the human diet may possess the potential to overwhelm the body's ability to maintain homeostasis and health as evidenced by the metabolic syndrome epidemic.
Some of the key mental health issues seen in teens are: There are many ways to prevent these health issues from occurring such as communicating well with a teen suffering from mental health issues. Mental health can be treated and be attentive to teens' behavior.
Achieving and maintaining health is an ongoing process, shaped by both the evolution of health care knowledge and practices as well as personal strategies and organized interventions for staying healthy. An important way to maintain your personal health is to have a healthy diet.
A healthy diet includes a variety of plant-based and animal-based foods that provide nutrients to your body. Such nutrients give you energy and keep your body running. Nutrients help build and strengthen bones, muscles, and tendons and also regulate body processes i. The food guide pyramid is a pyramid-shaped guide of healthy foods divided into sections. Each section shows the recommended intake for each food group i. Protein, Fat, Carbohydrates, and Sugars. Making healthy food choices is important because it can lower your risk of heart disease, developing some types of cancer , and it will contribute to maintaining a healthy weight.
The Mediterranean diet is commonly associated with health-promoting effects due to the fact that it contains some bioactive compounds like phenolic compounds , isoprenoids and alkaloids. Physical exercise enhances or maintains physical fitness and overall health and wellness. It strengthens muscles and improves the cardiovascular system. According to the National Institutes of Health , there are four types of exercise: Sleep is an essential component to maintaining health.
In children, sleep is also vital for growth and development. Ongoing sleep deprivation has been linked to an increased risk for some chronic health problems. In addition, sleep deprivation has been shown to correlate with both increased susceptibility to illness and slower recovery times from illness. Health science is the branch of science focused on health. There are two main approaches to health science: The science builds on many sub-fields, including biology , biochemistry , physics , epidemiology , pharmacology , medical sociology.
Applied health sciences endeavor to better understand and improve human health through applications in areas such as health education , biomedical engineering , biotechnology and public health. Organized interventions to improve health based on the principles and procedures developed through the health sciences are provided by practitioners trained in medicine , nursing , nutrition , pharmacy , social work , psychology , occupational therapy , physical therapy and other health care professions.
Clinical practitioners focus mainly on the health of individuals, while public health practitioners consider the overall health of communities and populations. Workplace wellness programs are increasingly adopted by companies for their value in improving the health and well-being of their employees, as are school health services in order to improve the health and well-being of children.
Public health has been described as "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals. The population in question can be as small as a handful of people or as large as all the inhabitants of several continents for instance, in the case of a pandemic.
Public health has many sub-fields, but typically includes the interdisciplinary categories of epidemiology , biostatistics and health services. Environmental health , community health , behavioral health , and occupational health are also important areas of public health.
The focus of public health interventions is to prevent and manage diseases, injuries and other health conditions through surveillance of cases and the promotion of healthy behavior , communities , and in aspects relevant to human health environments.
Its aim is to prevent health problems from happening or re-occurring by implementing educational programs , developing policies , administering services and conducting research. Vaccination programs and distribution of condoms to prevent the spread of communicable diseases are examples of common preventive public health measures, as are educational campaigns to promote vaccination and the use of condoms including overcoming resistance to such.
Public health also takes various actions to limit the health disparities between different areas of the country and, in some cases, the continent or world. One issue is the access of individuals and communities to health care in terms of financial, geographical or socio-cultural constraints to accessing and using services.
The great positive impact of public health programs is widely acknowledged. Due in part to the policies and actions developed through public health, the 20th century registered a decrease in the mortality rates for infants and children and a continual increase in life expectancy in most parts of the world.
For example, it is estimated that life expectancy has increased for Americans by thirty years since ,  and worldwide by six years since Personal health depends partially on the active, passive, and assisted cues people observe and adopt about their own health. These include personal actions for preventing or minimizing the effects of a disease, usually a chronic condition, through integrative care.
They also include personal hygiene practices to prevent infection and illness, such as bathing and washing hands with soap; brushing and flossing teeth ; storing, preparing and handling food safely ; and many others. Personal health also depends partially on the social structure of a person's life. The maintenance of strong social relationships , volunteering , and other social activities have been linked to positive mental health and also increased longevity.
One American study among seniors over age 70, found that frequent volunteering was associated with reduced risk of dying compared with older persons who did not volunteer, regardless of physical health status. Prolonged psychological stress may negatively impact health, and has been cited as a factor in cognitive impairment with aging, depressive illness, and expression of disease.
Relaxation techniques are physical methods used to relieve stress. Psychological methods include cognitive therapy , meditation , and positive thinking , which work by reducing response to stress. Improving relevant skills, such as problem solving and time management skills, reduces uncertainty and builds confidence, which also reduces the reaction to stress-causing situations where those skills are applicable.
In addition to safety risks, many jobs also present risks of disease, illness and other long-term health problems. Among the most common occupational diseases are various forms of pneumoconiosis , including silicosis and coal worker's pneumoconiosis black lung disease.
Asthma is another respiratory illness that many workers are vulnerable to. Workers may also be vulnerable to skin diseases, including eczema , dermatitis , urticaria , sunburn , and skin cancer.
As the number of service sector jobs has risen in developed countries, more and more jobs have become sedentary , presenting a different array of health problems than those associated with manufacturing and the primary sector. Contemporary problems, such as the growing rate of obesity and issues relating to stress and overwork in many countries, have further complicated the interaction between work and health. Many governments view occupational health as a social challenge and have formed public organizations to ensure the health and safety of workers.
Examples of these include the British Health and Safety Executive and in the United States , the National Institute for Occupational Safety and Health , which conducts research on occupational health and safety, and the Occupational Safety and Health Administration , which handles regulation and policy relating to worker safety and health.
From Wikipedia, the free encyclopedia. This article is about the human condition. For other uses, see Health disambiguation. Social determinants of health and Risk factor. This section has an unclear citation style. Carbohydrates range from simple monosaccharides glucose, fructose, galactose to complex polysaccharides starch. Fats are triglycerides , made of assorted fatty acid monomers bound to a glycerol backbone. Some fatty acids, but not all, are essential in the diet: Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen.
Some of the amino acids are convertible with the expenditure of energy to glucose and can be used for energy production just as ordinary glucose. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs naturally when atrophy takes place, or during periods of starvation.
Carbohydrates may be classified as monosaccharides , disaccharides or polysaccharides depending on the number of monomer sugar units they contain. They are a diverse group of substances, with a range of chemical, physical and physiological properties.
Monosaccharides contain one sugar unit, disaccharides two, and polysaccharides three or more. Monosaccharides include glucose , fructose and galactose.
The difference is that complex carbohydrates take longer to digest and absorb since their sugar units must be separated from the chain before absorption. The spike in blood glucose levels after ingestion of simple sugars is thought to be related to some of the heart and vascular diseases, which have become more common in recent times. Simple sugars form a greater part of modern diets than in the past, perhaps leading to more cardiovascular disease. The degree of causation is still not clear.
Simple carbohydrates are absorbed quickly, and therefore raise blood-sugar levels more rapidly than other nutrients. However, the most important plant carbohydrate nutrient, starch, varies in its absorption.
Gelatinized starch starch heated for a few minutes in the presence of water is far more digestible than plain starch, and starch which has been divided into fine particles is also more absorbable during digestion. The increased effort and decreased availability reduces the available energy from starchy foods substantially and can be seen experimentally in rats and anecdotally in humans. Additionally, up to a third of dietary starch may be unavailable due to mechanical or chemical difficulty.
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.
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.
Many studies have shown that consumption of unsaturated fats, particularly monounsaturated fats, is associated with better health in humans. Saturated fats, typically from animal sources, are next in order of preference, while trans fats are associated with a variety of disease and should be avoided. Saturated and some trans 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, but have properties useful in the food processing industry, such as rancidity resistance. Most fatty acids are not essential, meaning the body can produce them as needed, generally from other fatty acids and always by expending energy to do so. However, in humans, at least two fatty acids are essential and must be included in the diet.
An appropriate balance of essential fatty acids — omega-3 and omega-6 fatty acids — seems also important for health, though definitive experimental demonstration has been elusive.
Both of these "omega" long-chain polyunsaturated fatty acids are substrates for a class of eicosanoids known as prostaglandins , which have roles throughout the human body. They are hormones , in some respects. The omega-3 eicosapentaenoic acid EPA , which can be made in the human body from the omega-3 essential fatty acid alpha-linolenic acid LNA , or taken in through marine food sources, serves as a building block for series 3 prostaglandins e.
The omega-6 dihomo-gamma-linolenic acid DGLA serves as a building block for series 1 prostaglandins e.
An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins: In industrialized societies, people typically consume large amounts of processed vegetable oils, which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids.
Dietary fiber is a carbohydrate , specifically a polysaccharide, which is incompletely absorbed in humans and in some animals. Like all carbohydrates, when it is metabolized, it can produce four Calories kilocalories of energy per gram, but in most circumstances, it accounts for less than that because of its limited absorption and digestibility.
The two subcategories are insoluble and soluble fiber. Insoluble dietary fiber consists mainly of cellulose , a large carbohydrate polymer that is indigestible by humans, because humans do not have the required enzymes to break it down, and the human digestive system does not harbor enough of the types of microbes that can do so.
Soluble dietary fiber comprises a variety of oligosaccharides , waxes , esters , resistant starches, and other carbohydrates that dissolve or gelatinize in water. Many of these soluble fibers can be fermented or partially fermented by microbes in the human digestive system to produce short-chain fatty acids which are absorbed and therefore introduce some caloric content. Whole grains, beans and other legumes , fruits especially plums , prunes , and figs , and vegetables are good sources of dietary fiber.
Fiber is important to digestive health and is thought to reduce the risk of colon cancer. Fiber provides bulk to the intestinal contents, and insoluble fiber especially stimulates peristalsis — the rhythmic muscular contractions of the intestines which move digesta along the digestive tract. Some soluble fibers produce a solution of high viscosity ; this is essentially a gel, which slows the movement of food through the intestines.
Additionally, fiber, perhaps especially that from whole grains, may help lessen insulin spikes and reduce the risk of type 2 diabetes. Proteins are the basis of many animal body structures e. Each protein molecule is composed of amino acids which contain 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. Amino acids are soluble in the digestive juices within the small intestine, where they are absorbed into the blood. Once absorbed, they cannot be stored in the body, so they are either metabolized as required or excreted in the urine.
Proteins consist of amino acids in different proportions. The most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition. The synthesis of some amino acids can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress, and those are called conditionally essential. A vegetarian diet can adequately supply protein, support pregnancy, childhood and athletic endeavors,  and lower the risk of cardiovascular disease and cancer.
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 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 well-known is likely iodine in iodized salt which prevents goiter.
Many elements are required in smaller amounts microgram quantities , usually because they play a catalytic role in enzymes. 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: 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 phytochemicals have recently been discovered in food particularly in fresh vegetables , which may have desirable properties including antioxidant activity see below ; experimental demonstration has been suggestive but inconclusive. Other essential nutrients not classed as vitamins include essential amino acids see above , essential fatty acids see above , and the minerals discussed in the preceding section.
Vitamin deficiencies may result in disease conditions: Malnutrition refers to insufficient, excessive, or imbalanced consumption of nutrients. In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption. Although there are more people in the world who are malnourished due to excessive consumption, according to the United Nations World Health Organization , the greatest challenge in developing nations today is not starvation, but insufficient nutrition — the lack of nutrients necessary for the growth and maintenance of vital functions.
Research indicates that improving the awareness of nutritious meal choices and establishing long-term habits of healthy eating has a positive effect on a cognitive and spatial memory capacity, potentially increasing a student's potential to process and retain academic information.
Some organizations have begun working with teachers, policymakers, and managed foodservice contractors to mandate improved nutritional content and increased nutritional resources in school cafeterias from primary to university level institutions. Health and nutrition have been proven to have close links with overall educational success. Nutritional supplement treatment may be appropriate for major depression , bipolar disorder , schizophrenia , and obsessive compulsive disorder , the four most common mental disorders in developed countries.
Supplements that have been studied most for mood elevation and stabilization include eicosapentaenoic acid and docosahexaenoic acid each of which are an omega-3 fatty acid contained in fish oil , but not in flaxseed oil , vitamin B 12 , folic acid , and inositol. Cancer has become common in developing countries. According to a study by the International Agency for Research on Cancer , "In the developing world, cancers of the liver, stomach and esophagus were more common, often linked to consumption of carcinogenic preserved foods, such as smoked or salted food, and parasitic infections that attack organs.
Developed countries "tended to have cancers linked to affluence or a 'Western lifestyle' — cancers of the colon, rectum, breast and prostate — that can be caused by obesity, lack of exercise, diet and age. The same report recommends eating mostly foods of plant origin and aiming to meet nutritional needs through diet alone, while limiting consumption of energy -dense foods, red meat , alcoholic drinks and salt and avoiding sugary drinks , processed meat and moldy cereals grains or pulses legumes.
Protein consumption leads to an increase in IGF-1 , which plays a role in cancer development. Several lines of evidence indicate lifestyle-induced hyperinsulinemia and reduced insulin function i. For example, hyperinsulinemia and insulin resistance are strongly linked to chronic inflammation, which in turn is strongly linked to a variety of adverse developments such as arterial microinjuries and clot formation i.
Evidence indicates that diets possibly protective against metabolic syndrome include low saturated and trans fat intake and foods rich in dietary fiber , such as high consumption of fruits and vegetables and moderate intake of low-fat dairy products. The challenges facing global nutrition are disease, child malnutrition, obesity, and vitamin deficiency.
The most common non-infectious diseases worldwide, that contribute most to the global mortality rate, are cardiovascular diseases, various cancers, diabetes, and chronic respiratory problems, all of which are linked to poor nutrition. Nutrition and diet are closely associated with the leading causes of death, including cardiovascular disease and cancer.
Obesity and high sodium intake can contribute to ischemic heart disease, while consumption of fruits and vegetables can decrease the risk of developing cancer. Foodborne and infectious diseases can result in malnutrition, and malnutrition exacerbates infectious disease. Poor nutrition leaves children and adults more susceptible to contracting life-threatening diseases such as diarrheal infections and respiratory infections.
According to UNICEF, in , million children across the globe were underweight and one in four children, million, were stunted in growth. Childhood malnutrition is common and contributes to the global burden of disease. When humans are undernourished, they no longer maintain normal bodily functions, such as growth, resistance to infection, or have satisfactory performance in school or work.
Many children are born with the inherent disadvantage of low birth weight, often caused by intrauterine growth restriction and poor maternal nutrition, which results in worse growth, development, and health throughout the course of their lifetime. Data on global and regional food supply shows that consumption rose from in all regions. Diets became more diverse, with a decrease in consumption of cereals and roots and an increase in fruits, vegetables, and meat products.
Undernourishment, or hunger, according to the FAO, is dietary intake below the minimum daily energy requirement. The spike in food prices prevented many people from escaping poverty, because the poor spend a larger proportion of their income on food and farmers are net consumers of food. Malnutrition in industrialized nations is primarily due to excess calories and non-nutritious carbohydrates, which has contributed to the obesity epidemic affecting both developed and some developing nations.
Obesity is more prevalent amongst high income and higher middle income groups than lower divisions of income. Vitamins and minerals are essential to the proper functioning and maintenance of the human body. There are 20 trace elements and minerals that are essential in small quantities to body function and overall human health. Iron deficiency is the most common inadequate nutrient worldwide, affecting approximately 2 billion people.
Vitamin A plays an essential role in developing the immune system in children, therefore, it is considered an essential micronutrient that can greatly affect health.