A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to , , fungus and . Nutrients can be incorporated into cells for metabolism or excretion by cells to create non-cellular structures such as hair, scales, , or . Some nutrients can be metabolically converted into smaller molecules in the process of releasing energy such as for , , proteins and fermentation products (ethanol or vinegar) leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the that are combined to create , a subset of , and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. fungus live on dead or living organic matter and meet nutrient needs from their host.
Different types of organisms have different essential nutrients. Ascorbic acid (vitamin C) is essential to humans and some animal species but most other animals and many plants are able to synthesize it. Nutrients may be organic compound or inorganic: organic compounds include most compounds containing carbon, while all other chemicals are inorganic. Inorganic nutrients include nutrients such as iron, selenium, and zinc, while organic nutrients include, protein, fats, sugars and vitamins.
A classification used primarily to describe nutrient needs of animals divides nutrients into macronutrients and . Consumed in relatively large amounts ( or ), macronutrients (carbohydrates, , proteins, water) are primarily used to generate energy or to incorporate into tissues for growth and repair. Micronutrients are needed in smaller amounts ( or ); they have subtle biochemistry and physiology roles in cellular processes, like vascular functions or action potential. 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 the amount required to prevent deficiency and provide macronutrient and micronutrient guides for both lower and upper limits of intake. In many countries, regulations require that food product labels display information about the amount of any macronutrients and micronutrients present in the food in significant quantities. Nutrients in larger quantities than the body needs may have harmful effects. Edible plants also contain thousands of compounds generally called which have unknown effects on disease or health including a diverse class with non-nutrient status called which remain poorly understood as of 2024.
Types
Macronutrients
- The humans consume in the largest quantities are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulphur, summarized as CHNOPS.
- The chemical compounds that humans consume in the largest quantities and provide bulk energy are classified as , , and . Water must be also consumed in large quantities but does not provide caloric value.
- Calcium, sodium, potassium, magnesium, and chloride ions, along with phosphorus and sulfur, are listed with macronutrients because they are required in large quantities compared to , i.e., vitamins and other minerals, the latter often described as trace or ultratrace minerals.
Macronutrients provide energy:
- are compounds made up of types of sugar. Carbohydrates are classified according to their number of sugar units: (such as glucose and fructose), (such as sucrose and lactose), , and (such as starch, glycogen, and cellulose).
- are that consist of joined by . Since the body cannot manufacture some of the amino acids (termed essential amino acids), the diet must supply them. Through digestion, are broken down by back into free amino acids.
- consist of a glycerin molecule with three attached. Fatty acid molecules contain a -COOH group attached to unbranched hydrocarbon chains connected by single bonds alone (Saturated fat) or by both double and single bonds (Unsaturated fat). Fats are needed for construction and maintenance of , to maintain a stable body temperature, and to sustain the health of skin and hair. Because the body does not manufacture certain fatty acids (termed essential fatty acids), they must be obtained through one's diet.
| + !Biomolecule !Kilocalories per 1 gram | |
| Protein | 4 |
| Carbohydrate | 4 |
| Ethanol | 7 |
| Fat | 9 |
Micronutrients
- , such as potassium, sodium, and iron, are elements native to Earth, and cannot be synthesized. They are required in the diet in microgram or milligram amounts. As plants obtain minerals from the soil, dietary minerals derive directly from plants consumed or indirectly from edible animal sources.
- are organic compounds required in microgram or milligram amounts. The importance of each dietary vitamin was first established when it was determined that a disease would develop if that vitamin was absent from the diet.
Essentiality
Essential nutrients
Amino acids
Fatty acids
Vitamins and vitamers
Minerals
The essential nutrient trace elements for humans, listed in order of recommended dietary allowance (expressed as a mass), are potassium, chloride, sodium, calcium, phosphorus, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, and 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.
Choline
/ref> 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
Non-essential
Non-nutrients
According to the U.S. Department of Agriculture, based on NHANES 2013–2014 surveys, women ages 20 and up consume on average 6.8grams 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 , respectively. Alcoholic beverages are considered empty calorie foods because, while providing energy, they contribute no essential nutrients.
By definition, include all nutritional and non-nutritional components of edible plants. Included as nutritional constituents are provitamin A , whereas those without nutrient status are diverse , , resveratrol, and that are present in numerous plant foods. Some 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 provide antioxidant benefits.
An inadequate amount of a nutrient is a deficiency. Deficiencies can be due to several causes, including an inadequacy in nutrient intake, called a dietary deficiency, or any of several conditions that interfere with the utilization of a nutrient within an organism. Some of the conditions that can interfere with nutrient utilization include problems with nutrient absorption, substances that cause a greater-than-normal need for a nutrient, conditions that cause nutrient destruction, and conditions that cause greater nutrient excretion. Nutrient toxicity occurs when excess consumption of a nutrient does harm to an organism.
In the United States and Canada, recommended dietary intake levels of essential nutrients are based on the minimum level that "will maintain a defined level of nutriture in an individual", a definition somewhat different from that used by the World Health Organization and Food and Agriculture Organization of a "basal requirement to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy".
In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. Dietary Reference Intakes for Japanese (2010) National Institute of Health and Nutrition, Japan For example, for vitamin C, recommended intakes range from 40 mg/day in India to 155 mg/day for the European Union. The table below shows U.S. Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins and minerals, PRIs for the European Union (same concept as RDAs), followed by what three government organizations deem to be the safe upper intake. RDAs are set higher than EARs to cover people with higher-than-average needs. Adequate Intakes (AIs) are set when there is insufficient information to establish EARs and RDAs. Countries establish tolerable upper intake levels, also referred to as upper limits (ULs), based on amounts that cause adverse effects. Governments are slow to revise information of this nature. For the U.S. values, except calcium and vitamin D, all data date from 1997 to 2004.
* The daily recommended amounts of niacin and magnesium are higher than the tolerable upper limit because, for both nutrients, the ULs identify the amounts that will not increase the risk of adverse effects when the nutrients are consumed as a serving of a dietary supplement. Magnesium supplementation above the UL may cause diarrhea. Supplementation with niacin above the UL may cause flushing of the face and a sensation of body warmth. Each country or regional regulatory agency decides on a safety margin below when symptoms occur so that the ULs may differ based on the source.
EAR U.S. Estimated Average Requirements.
RDA U.S. Recommended Dietary Allowances; higher for adults than children and may be even higher for pregnant or lactating women.
AI U.S. Adequate Intake; AIs are established when there is insufficient information to set EARs and RDAs.
PRI Population Reference Intake is the European Union equivalent of RDA; it is higher for adults than for children and maybe even higher for pregnant or lactating women. For Thiamin and Niacin, the PRIs are expressed as amounts per megajoule (239 kilocalories) of food energy consumed.
Upper Limit Tolerable upper intake levels.
ND ULs have not been determined.
NE EARs, PRIs, or AIs have not yet been established or will not be (EU does not consider chromium an essential nutrient).
Deficiencies and toxicity
μg mg μg μg mg mg mg mg mg mg μg μg μg mg mg mg μg μg mg μg mg mg mg μg mg mg μg mg mg
Plant
See also
External links
target="_blank" rel="nofollow"> USDA. Dietary Reference Intakes
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