Nutrition is the biochemistry and physiology process by which an organism uses food to support its life. It includes ingestion, absorption, assimilation, biosynthesis, catabolism and excretion.
Nutritional groups
Organisms primarily provide themselves with carbon in one of two ways:
autotrophy (the self-production of organic food) and
heterotrophy (the consumption of existing organic carbon). Combined with the source of energy, either light (
phototrophy) or chemical (
chemotrophy), there are four primary nutritional groups for organisms.
Nutrients
Nutrients are substances used by an organism to survive, grow, and reproduce. The seven major classes of relevant nutrients for animals (including humans) are
carbohydrates,
dietary fiber,
,
,
dietary minerals,
, and
water. Nutrients can be grouped as either
(carbohydrates, dietary fiber, fats, proteins, and water needed in
gram quantities) or
(vitamins and minerals needed in
milligram or
microgram quantities).
Diet
In nutrition, the
diet of an organism is the sum of foods it eats, which is largely determined by the availability and
palatability of foods.
Human nutrition
Human nutrition deals with the provision of essential nutrients from food that are necessary to support human
life and
health.
In humans, poor nutrition can cause deficiency-related diseases such as
blindness,
anemia,
scurvy,
preterm birth,
stillbirth and
cretinism,
or nutrient excess health-threatening conditions such as
obesity and metabolic syndrome;
[ Metabolic syndrome – PubMed Health. Ncbi.nlm.nih.gov. Retrieved on 2011-10-17.] and such common chronic systemic diseases as cardiovascular disease,
[ Omega-3 fatty acids. Umm.edu (5 October 2011). Retrieved on 2011-10-17.] diabetes,
[ Diabetes Diet and Food Tips: Eating to Prevent and Control Diabetes . Helpguide.org. Retrieved on 2011-10-17.] and
osteoporosis.
[ Dietary Supplement Fact Sheet: Vitamin D. Office of Dietary Supplements, US National Institutes of Health 17 August 2021.] Undernutrition can lead to
wasting in acute cases, and
stunted growth of
marasmus in chronic cases of
malnutrition.
Animal nutrition
Animal nutrition focuses on the dietary nutrient needs of
animals, often in comparison (or contrast) to other organisms like plants.
Carnivore and
herbivore diets are contrasting, with basic
nitrogen and
carbon proportions varying 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. Animals generally have a higher requirement of energy in comparison to plants.
Plant nutrition
Plant nutrition is the study of the
that are necessary for plant growth.
There are several principles that apply to plant nutrition. 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 can 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 the air, and hydrogen, which is obtained from water.
Plants uptake essential elements from the soil through their and from the air (consisting of mainly nitrogen and oxygen) through their Leaf. 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. Nutrient uptake in the soil is achieved by cation exchange, wherein pump (H+) into the soil through . These hydrogen ions displace 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.[Lindemann, W.C. and Glover C.R. (2003) Nitrogen Fixation by Legumes. New Mexico State University/]
See also
Bibliography
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Curley, S., and Mark (1990). The Natural Guide to Good Health, Lafayette, Louisiana, Supreme Publishing
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External links
