Nutrient: Difference between revisions

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{{Short description|Substance that an organism uses to live}}

A classification used primarily to describe nutrient needs of animals divides nutrients into [[list of macronutrients|macronutrients]] and [[micronutrient]]s. Consumed in relatively large amounts ([[gram]]s or [[ounce]]s), macronutrients (carbohydrates, [[fat]]s, proteins, water) are primarily used to generate energy or to incorporate into tissues for growth and repair. Micronutrients are needed in smaller amounts ([[milligram]]s or [[microgram]]s); they have subtle [[biochemistry|biochemical]] and [[physiology|physiological]] roles in cellular processes, like [[vascular smooth muscle|vascular functions]] or [[action potential|nerve conduction]]. Inadequate amounts of essential nutrients, or diseases that interfere with absorption, result in a deficiency state that compromises growth, survival and reproduction. Consumer advisories for dietary nutrient intakes, such as the United States [[Dietary Reference Intake]], are based on deficiency outcomes and provide macronutrient and micronutrient guides for both lower and [[Tolerable upper intake levels|upper limits]] of intake. In many countries, macronutrients and micronutrients in significant content are required by regulations to be displayed on food product labels. Nutrients in larger quantities than the body needs may have harmful effects. Edible plants also contain thousands of compounds generally called [[phytochemical]]s which have unknown effects on disease or health, including a diverse class with non-nutrient status called [[polyphenol]]s, which remain poorly understood as of 2017.

{{Main|Nutrition}}

Macronutrients are defined in several ways.

* The [[chemical element]]s humans consume in the largest quantities are [[carbon]], [[hydrogen]], [[nitrogen]], [[oxygen]], [[phosphorus]], and [[sulphur]], summarized as [[CHNOPS]].

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Micronutrients support metabolism.

* [[Dietary mineral]]s are generally trace elements, salts, or ions such as copper and iron. Some of these minerals are essential to human metabolism.

== Essentiality == <!--T:9-->

{{anchor|Essential nutrients}}

An '''essential nutrient''' is a nutrient required for normal physiological function that cannot be synthesized in the body&nbsp;– either at all or in sufficient quantities&nbsp;– and thus must be obtained from a [[Diet (nutrition)|dietary]] source. Apart from [[water]], which is universally required for the maintenance of [[homeostasis]] in mammals, essential nutrients are indispensable for various cellular [[metabolic process]]es and for the maintenance and function of tissues and organs. The nutrients considered essential for humans comprise nine amino acids, two fatty acids, thirteen [[vitamin]]s, fifteen [[Mineral (nutrient)|minerals]] and [[choline]]. In addition, there are several molecules that are considered conditionally essential nutrients since they are indispensable in certain developmental and pathological states.

{{Main|Essential amino acid}}

An essential amino acid is an amino acid that is required by an organism but cannot be synthesized ''[[de novo synthesis|de novo]]'' by it, and therefore must be supplied in its diet. Out of the twenty standard protein-producing amino acids, nine cannot be [[endogenous]]ly synthesized by humans: [[phenylalanine]], [[valine]], [[threonine]], [[tryptophan]], [[methionine]], [[leucine]], [[isoleucine]], [[lysine]], and [[histidine]].

{{Main|Essential fatty acid}}

Essential fatty acids (EFAs) are [[fatty acid]]s that humans and other animals must ingest because the body requires them for good health but cannot [[Biosynthesis|synthesize]] them. Only two fatty acids are known to be essential for humans: [[alpha-linolenic acid]] (an [[omega-3 fatty acid]]) and [[linoleic acid]] (an [[omega-6 fatty acid]]).

{{Main|Vitamin}}

Vitamins are organic molecules essential for an organism that are not classified as amino acids or fatty acids. They commonly function as [[enzymatic cofactor]]s, metabolic regulators or [[antioxidant]]s. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules (e.g. [[vitamin E]] includes [[tocopherol]]s and [[tocotrienol]]s): vitamins A, C, D, E, K, [[thiamine]] (B₁), [[riboflavin]] (B₂), [[Niacin (nutrient)|niacin]] (B₃), [[pantothenic acid]] (B₅), [[pyridoxine]] (B₆), [[biotin]] (B₇), [[folate]] (B₉), and [[cobalamin]] (B₁₂). The requirement for vitamin D is conditional, as people who get sufficient exposure to ultraviolet light, either from the sun or an artificial source, synthesize vitamin D in the skin.

{{Main|Mineral (nutrient)}}

Minerals are the [[exogenous]] [[chemical element]]s indispensable for life. Although the four elements: [[carbon]], [[hydrogen]], [[oxygen]], and [[nitrogen]], are essential for life, they are so plentiful in food and drink that these are not considered nutrients and there are no recommended intakes for these as minerals. The need for nitrogen is addressed by requirements set for protein, which is composed of nitrogen-containing amino acids. [[Sulfur]] is essential, but again does not have a recommended intake. Instead, recommended intakes are identified for the sulfur-containing amino acids methionine and cysteine.

The essential nutrient elements for humans, listed in order of [[Reference Daily Intake|Recommended Dietary Allowance]] (expressed as a mass), are [[potassium]], [[chloride]], [[sodium]], [[calcium]], [[phosphorus]], [[magnesium]], [[iron]], [[zinc]], [[manganese]], [[copper]], [[iodine]], [[chromium]], [[molybdenum]], [[selenium]]. Additionally, [[cobalt]] is a component of Vitamin B₁₂ which is essential. There are other minerals which are essential for some plants and animals, but may or may not be essential for humans, such as [[boron]] and [[silicon]].

{{Main|Choline}}

Choline is an essential nutrient. The cholines are a family of water-soluble [[quaternary ammonium compound]]s. Choline is the parent compound of the cholines class, consisting of ethanolamine having three methyl substituents attached to the amino function. Healthy humans fed artificially composed diets that are deficient in choline develop fatty liver, liver damage, and muscle damage. Choline was not initially classified as essential because the human body can produce choline in small amounts through phosphatidylcholine metabolism.

Conditionally essential nutrients are certain organic molecules that can normally be synthesized by an organism, but under certain conditions in insufficient quantities. In humans, such conditions include [[Preterm birth|premature birth]], limited nutrient intake, rapid growth, and certain disease states. [[Inositol]], [[taurine]], [[arginine]], [[glutamine]] and [[nucleotides]] are classified as conditionally essential and are particularly important in neonatal diet and metabolism.

Non-essential nutrients are substances within foods that can have a significant impact on health. Insoluble [[dietary fiber]] is not absorbed in the human digestive tract, but is important in maintaining the bulk of a [[bowel movement]] to avoid [[constipation]]. [[Soluble fiber]] can be metabolized by bacteria residing in the large intestine. Soluble fiber is marketed as serving a [[Prebiotic (nutrition)|prebiotic]] function with claims for promoting "healthy" intestinal bacteria. Bacterial metabolism of soluble fiber also produces [[short-chain fatty acid]]s like [[butyric acid]], which may be absorbed into intestinal cells as a source of [[food energy]].

[[Ethanol]] (C₂H₅OH) is not an essential nutrient, but it does supply approximately {{convert|7|kcal|kJ|order=flip|abbr=off}} of food energy per gram. For spirits (vodka, gin, rum, etc.) a standard serving in the United States is {{convert|1+1/2|USfloz|ml|order=flip|abbr=off}}, which at 40%{{nbsp}}ethanol (80{{nbsp}}proof) would be 14 grams and {{convert|98|kcal|kJ|order=flip|abbr=on}}. At 50%{{nbsp}}alcohol, 17.5&nbsp;g and {{convert|122.5|kcal|kJ|order=flip|abbr=on}}. Wine and beer contain a similar amount of ethanol in servings of {{convert|5|and|12|USfloz|mL|order=flip|abbr=on}}, respectively, but these beverages also contribute to food energy intake from components other than ethanol. A {{convert|5|USfloz|mL|order=flip|abbr=on}} serving of wine contains {{convert|100|to|130|kcal|kJ|order=flip|abbr=on}}. A {{convert|12|USfloz|mL|order=flip|abbr=on}} serving of beer contains {{convert|95|to|200|kcal|kJ|order=flip|abbr=on}}. According to the U.S. Department of Agriculture, based on [[NHANES]] 2013–2014 surveys, women ages 20 and up consume on average 6.8{{nbsp}}grams of alcohol per day and men consume on average 15.5 grams per day. Ignoring the non-alcohol contribution of those beverages, the average ethanol contributions to daily food energy intake are {{convert|48|and|108|kcal|kJ|order=flip|abbr=on}}, respectively. Alcoholic beverages are considered [[empty calorie]] foods because, while providing energy, they contribute no essential nutrients.

By definition, [[phytochemical]]s include all nutritional and non-nutritional components of edible plants. Included as nutritional constituents are [[provitamin]] A [[carotenoid]]s, whereas those without nutrient status are diverse [[polyphenol]]s, [[flavonoid]]s, [[resveratrol]], and [[lignan]]s – often claimed to have [[antioxidant]] effects – that are present in numerous plant foods. A number of phytochemical compounds are under preliminary research for their potential effects on human diseases and health. However, the qualification for nutrient status of compounds with poorly defined properties ''[[in vivo]]'' is that they must first be defined with a [[Dietary Reference Intake]] level to enable accurate food labeling, a condition not established for most phytochemicals that are claimed to be antioxidant nutrients.

''See [[Vitamin]], [[Mineral (nutrient)]], [[Protein (nutrient)]]''

'''NE'''  EARs, PRIs or AIs have not yet been established or will not be (EU does not consider chromium an essential nutrient).

{{Main|Plant nutrition|Fertilizer}}

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{{Commons category|Nutrients}}

* [https://web.archive.org/web/20161008111338/https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/recommended_intakes_individuals.pdf USDA. Dietary Reference Intakes]

[[Category:Nutrition]]

[[Category:Essential nutrients]]