Nutrition is the biochemical and physiological process by which an organism uses food and water to support its life. The intake of these substances provides organisms with nutrients (divided into macro- and micro-) which can be metabolized to create energy and chemical structures; too much or too little of an essential nutrient can cause malnutrition. Nutritional science, the study of nutrition as a hard science, typically emphasizes human nutrition.
The type of organism determines what nutrients it needs and how it obtains them. Organisms obtain nutrients by consuming organic matter, consuming inorganic matter, absorbing light, or some combination of these. Some can produce nutrients internally by consuming basic elements, while others must consume other organisms to obtain pre-existing nutrients. All forms of life require carbon, energy, and water as well as various other molecules. Animals require complex nutrients such as carbohydrates, lipids, and proteins, obtaining them by consuming other organisms. Humans have developed agriculture and cooking to replace foraging and advance human nutrition. Plants acquire nutrients through the soil and the atmosphere. Fungi absorb nutrients around them by breaking them down and absorbing them through the mycelium.
History
Scientific analysis of food and nutrients began during the chemical revolution in the late 18th century. Chemists in the 18th and 19th centuries experimented with different elements and food sources to develop theories of nutrition. Modern nutrition science began in the 1910s as individual micronutrients began to be identified. The first vitamin to be chemically identified was thiamine in 1926, and vitamin C was identified as a protection against scurvy in 1932. The role of vitamins in nutrition was studied in the following decades. The first recommended dietary allowances for humans were developed to address fears of disease caused by food deficiencies during the Great Depression and the Second World War. Due to its importance in human health, the study of nutrition has heavily emphasized human nutrition and agriculture, while ecology is a secondary concern.
Nutrients
Nutrients are substances that provide energy and physical components to the organism, allowing it to survive, grow, and reproduce. Nutrients can be basic elements or complex macromolecules. Approximately 30 elements are found in organic matter, with nitrogen, carbon, and phosphorus being the most important. Macronutrients are the primary substances required by an organism, and micronutrients are substances required by an organism in trace amounts. Organic micronutrients are classified as vitamins, and inorganic micronutrients are classified as minerals. Over-nutrition of macronutrients is a major cause of obesity and increases the risk of developing various non-communicable diseases (NCDs), including type 2 diabetes, stroke, hypertension, coronary heart disease, osteoporosis, and some forms of cancer. Nutrients can also be classified as essential or nonessential, with essential meaning the body cannot synthesize the nutrient on its own.
Nutrients are absorbed by the cells and used in metabolic biochemical reactions. These include fueling reactions that create precursor metabolites and energy, biosynthetic reactions that convert precursor metabolites into building block molecules, polymerizations that combine these molecules into macromolecule polymers, and assembly reactions that use these polymers to construct cellular structures.
Nutrient deficiency
Nutrient deficiencies, known as malnutrition, occur when an organism does not have the nutrients that it needs. A deficiency is not the same as a nutrient inadequacy which occurs when the intake of nutrients is above the level of deficiency, but below the recommended dietary level. This may lead to hidden symptoms of nutrient deficiency that are difficult to identify. Nutrient deficiency may be caused by a sudden decrease in nutrient intake or by an inability to absorb essential nutrients. Not only is malnutrition the result of a lack of necessary nutrients, but it can also be a result of other illnesses and health conditions. When this occurs, an organism will adapt by reducing energy consumption and expenditure to prolong the use of stored nutrients. It will use stored energy reserves until they are depleted.
A balanced diet includes appropriate amounts of all essential and non-essential nutrients. These can vary by age, weight, sex, physical activity levels, and more. A lack of just one essential nutrient can cause bodily harm, just as an overabundance can cause toxicity. The Daily Reference Values keep the majority of people from nutrient deficiencies. DRVs are not recommendations but a combination of nutrient references to educate professionals and policymakers on what the maximum and minimum nutrient intakes are for the average person.
Data Source: Wikipedia | Generated for EasyPro.sbs
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