Nutrition - How Nutrients Interact To Support Life.

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Nutrition in it's totality is an extremely broad subject. This is due to the fact that, all the many life forms that exist, have different metabolic processes and nutritional needs. The focus in this article therefore, is not nutrition in regards to the entirety of life, but rather nutrition in regards to human beings.


Nutrition is life.

Nutrition differs depending on species.

Nutrition is the interaction of nutrients and other substances in food (like fiber) in relation to maintenance, growth, reproduction, and health of an organism. It includes nutrient intake, absorption, assimilation, biosynthesis, catabolism and excretion. In other words, nutrition is the process by which a living organism sources for, absorbs, assimilates, and utilizes nutrients in order to maintain its life and health.

It should be noted however, that life as a whole is divided into various forms which include; plants, animals, fungi, protists, archaea, and bacteria. These different forms of life are each divided up further into various other different life forms e.g. animals are divided broadly into vertebrates and invertebrates.

Invertebrates are divided up further into other life forms like; arthropods, molluscs, roundworms, ringed worms, flatworms, and other phyla in Ecdysozoa and Spiralia. Vertebrates on the other hand are divided up further into fishes, amphibians, reptiles, birds, and mammals.

Each of these life forms is also further divided up into other life forms e.g. mammals which fall under vertebrates are divided up further into 21 different other life forms including; Rodentia, Chiroptera, Soricomorpha, Primates, Carnivora, Artiodactyla, Diprotodontia, etc.

Each of these life forms is further divided up into other different life forms e.g. primates are divided up further into various other life forms including; hominidae, hylobatidae, cebidae, aotidae, etc. Each of these life forms is divided up further into other life forms e.g. hominidae are divided into different other life forms of which humans are one of them.

Given the above explanation, it is suffice to note that nutrition as a whole is an extremely broad subject due to the fact that all the many life forms that exist, have different metabolic processes and nutritional needs. The focus in this writing therefore, is not nutrition in regards to the entirety of life, but rather nutrition in regards to human beings.

Human nutrition is the provision of nutrients essential to human life.

Human nutrition is the key to human health and vitality.

Human Nutrition

Human nutrition is about the provision of essential nutrients necessary to support human life and health. The nutrients required by the human body to function are; carbohydrates, fats, minerals, proteins, vitamins, and water. These nutrient classes are categorized as either macronutrients (needed in large amounts) or micronutrients (needed in smaller quantities). The macronutrients are carbohydrates, fats, proteins, and water. The micronutrients are minerals and vitamins.

Human nutrition is studied for research on diet and health, metabolism ageing and disease and global food security. As molecular biology, biochemistry and genetics advance, nutrition has become more focused on the steps of biochemical sequences through which substances inside us and other living organisms are transformed from one form to another - metabolism and metabolic pathways.

Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet. In addition, nutrition involves identifying how certain diseases, conditions or health problems such as poor diet (malnutrition), food allergies, metabolic diseases, etc. may be caused by dietary factors.

The way we eat is almost as important as what we eat. Good nutrition can include consuming high quality foods like fruits, vegetables, starchy foods, foods high in fiber, foods rich in protein, and essential fatty acids (EFA). It can also include methods of storage and preparation of food that preserve nutrients from oxidation, heat or leaching, and that reduce risk of foodborne illness. It can also include spacing out meals throughout the day, having small portions more regularly, say, five times in a day.


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Humans are omnivorous creatures, they consume foods from both plant and animal origins as a source of nutrients but also from supplements.


Food is any substance consumed to provide nutritional support. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. Some foods not from animal or plant sources include various edible fungi, especially mushrooms. Fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina. Inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient.


A dietary supplement is either intended to provide nutrients in order to increase the quantity of their consumption, or to provide non-nutrient chemicals which are claimed to have a biologically beneficial effect. Supplements as generally understood include vitamins, minerals, fiber, fatty acids, or amino acids, among other substances. There are more than 50,000 dietary supplements available. For those who fail to consume a balanced diet, certain supplements "may have value." An exception is vitamin D, which is recommended in Nordic countries due to weak sunlight and also in people of dark skin.


The digestive system is responsible for the break down of food before it's absorbed by the body.

Metabolism is the set of chemical reactions within the body cells, that produce the energy and compounds the body needs to function.



Once food has been ingested, it has to be broken down before it is absorbed by the body. This break down of the ingested food into its respective components occurs in the digested system. The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). In this system, the process of digestion has many stages, the first of which starts in the mouth. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.

Chewing, in which food is mixed with saliva begins the process of digestion. This produces a bolus which can be swallowed down the esophagus and into the stomach. Here it is mixed with gastric juice until it passes into the duodenum where it is mixed with a number of enzymes produced by the pancreas. Saliva also contains a catalytic enzyme called amylase which starts to act on food in the mouth. Another digestive enzyme called lingual lipase is secreted by some of the lingual papillae on the tongue and also from serous glands in the main salivary glands. Digestion is helped by the mastication of food by the teeth and also by the muscular actions of peristalsis and segmentation contractions. Gastric juice in the stomach is essential for the continuation of digestion as is the production of mucus in the stomach.

Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of the gastrointestinal tract. This initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system. Most of the digestion of food takes place in the small intestine. Water and some minerals are reabsorbed back into the blood in the colon of the large intestine. The waste products of digestion are passed out via the rectum.


Once the food has been broken down by the digestive system to its respective components and these components absorbed by the body, the process of metabolism kicks in. Metabolism is the set of life-sustaining chemical transformations within the cells of organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism.

Metabolism is usually divided into two categories: catabolism, the breaking down of organic matter for example, the breaking down of glucose to pyruvate, by cellular respiration, and anabolism, the building up of components of cells such as proteins and nucleic acids. Usually, breaking down releases energy and building up consumes energy.

The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts that allow the reactions to proceed more rapidly. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or to signals from other cells.




Poor nutrition is a chronic problem often linked to poverty, poor nutrition understanding and practices, and deficient sanitation and food security. Malnutrition and its consequences are immense contributors to deaths and disabilities worldwide. Promoting good nutrition helps children grow, promotes human development and eradication of poverty.


Malnutrition is a condition that results from eating a diet in which nutrients are either not enough or are too much such that the diet causes health problems. It may involve calories, protein, carbohydrates, vitamins or minerals. Not enough nutrients is called undernutrition or under-nourishment while too much is over-nutrition. Malnutrition is often used to specifically refer to undernutrition where an individual is not getting enough calories, protein, or micronutrients. If undernutrition occurs during pregnancy, or before two years of age, it may result in permanent problems with physical and mental development.

There are two main types of undernutrition: protein-energy malnutrition and dietary deficiencies. Protein-energy malnutrition has two severe forms: marasmus (a lack of protein and calories) and kwashiorkor (a lack of just protein). Common micronutrient deficiencies include: a lack of iron, iodine, and vitamin A. During pregnancy, due to the body's increased need, deficiencies may become more common.

While you need to consume a certain amount of nutrients for good health, consuming too much can cause health problems. It is recommended to get most of your nutrients through food and only to use supplements if necessary to archive a balanced diet without going over your recommended calories for the day. If you do take supplements, avoid taking large doses of any single nutrient unless instructed to do so by your doctor.


Over consumption of carbohydrates and fats, can lead to obesity

Over consumption of simple sugars can lead to diabetes

Over consumption of fats can lead to cardiovascular diseases

One of the various other symptoms from over consumption of vitamins or minerals is diarrhea



Nutrient amounts include those from both food and supplement sources




In nutrition, the amount of nutrient intake considered to be healthy in a diet is referred to as a recommended dietary allowance (RDA). Recommended Dietary Allowances (RDAs) were a set of nutrition recommendations that evolved into both the Dietary Reference Intake (DRI) system of nutrition recommendations (which still defines RDA values) and the RDIs used for food labelling.

Reference intakes are a means of communicating maximum recommended nutrient intake to the public. Reference intakes (RIs) are not intended as targets, as energy and nutrient requirements are different for all people. But they give a useful indication of how much energy the average person needs and how a particular nutrient fits into your daily diet.

Unless otherwise, RI values are based on an average-sized woman doing an average amount of physical activity. This is to reduce the risk of people with lower energy requirements eating too much, as well as to provide clear and consistent information on food labels.

The following list is for RIs (Recommended Intakes) based on a caloric intake of 2000 kcal (8400 kJ), for adults and children four or more years of age.


For vitamins and minerals, the RDIs (adult 100% Daily Values) are given in the following list of the Dietary Reference Intakes (maximized over sex and age groups, excluding women who are pregnant or lactating):






Identifying the nutrients in food is one thing, the other essential is keeping nutritious food nutritious by preserving and protecting its nutrients. This is done through food processing which is a word that some people look at as nutritionally dirty. Without food processing techniques however, we would need to gather and eat our food immediately before it spoils. Thanks to the effective food processing techniques, we don’t have to.

Food processing typically involves activities such as mincing and macerating, liquefaction, emulsification, cooking (such as boiling, broiling, frying, or grilling); pickling, pasteurization, and many other kinds of preservation; and canning or other packaging. (Primary-processing such as dicing, slicing, freezing or drying when leading to secondary products are also included).

Benefits of food processing include toxin removal, preservation, easing marketing and distribution tasks, and increasing food consistency. In addition, it increases yearly availability of many foods, enables transportation of delicate perishable foods across long distances and makes many kinds of foods safe to eat by de-activating spoilage and pathogenic micro-organisms. Modern supermarkets would not exist without modern food processing techniques, and long voyages would not be possible.

Processed foods are usually less susceptible to early spoilage than fresh foods and are better suited for long distance transportation from the source to the consumer. When they were first introduced, some processed foods helped to alleviate food shortages and improved the overall nutrition of populations as it made many new foods available to the masses.

Processing can also reduce the incidence of food borne disease. Fresh materials, such as fresh produce and raw meats, are more likely to harbor pathogenic micro-organisms (e.g. Salmonella) capable of causing serious illnesses.

The extremely varied modern diet is only truly possible on a wide scale because of food processing. Transportation of more exotic foods, as well as the elimination of much hard labor gives the modern eater easy access to a wide variety of food unimaginable to their ancestors.


Any processing of food can decrease its nutritional density. The amount of nutrients lost depends on the food and processing method. For example, heat destroys vitamin C. Therefore, canned fruits possess less vitamin C than their fresh alternatives.

Using food additives represents another safety concern. The health risks of any given additive vary greatly from person to person; for example using sugar as an additive endangers diabetics. In the European Union, only European Food Safety Authority (EFSA) approved food additives (e.g., sweeteners, preservatives, stabilizers) are permitted at specified levels for use in food products. Approved additives receive an E number (E for Europe), simplifying communication about food additives included in the ingredients' list for all the different languages spoken in the EU. As effects of chemical additives are learnt, changes to laws and regulatory practices are made to make such processed foods safer.

Food processing is typically a mechanical process that utilizes large mixing, grinding, chopping and emulsifying equipment in the production process. These processes introduce a number of contamination risks. As a mixing bowl or grinder is used over time, metal parts in contact with food will tend to fail and fracture. This type of failure will introduce into the product stream small to large metal contaminants. Further processing of these metal fragments will result in downstream equipment failure and the risk of ingestion by the consumer. Food manufacturers utilize industrial metal detectors to detect and reject automatically any metal fragment. Large food processors will utilize many metal detectors within the processing stream to reduce both damage to processing machinery as well as risk to consumer health.


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