Nutrition
Animals require complex nutrients such as carbohydrates, lipids, and proteins, obtaining them by consuming other organisms.
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.
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.
[4] Nutrients are substances that provide energy and physical components to the organism, allowing it to survive, grow, and reproduce.
Carbohydrates, protein and fat play major roles in ensuring the quality of life, health and longevity of the organism.
[12] Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyclic.
[14] Without proper nutrient cycling, there would be risk of change in oxygen levels, climate, and ecosystem function.
When this occurs, an organism will adapt by reducing energy consumption and expenditure to prolong the use of stored nutrients.
[22] Food labels also use DRVs as a reference to create safe nutritional guidelines for the average healthy person.
[28] Carbohydrates are broken down to produce glucose and short-chain fatty acids, and they are the most abundant nutrients for herbivorous land animals.
Major advances in economics and technology during the 20th century allowed mass production and food fortification to better meet the nutritional needs of humans.
Nutrition in humans is balanced with eating for pleasure, and optimal diet may vary depending on the demographics and health concerns of each person.
Cultivation of cereals and production of bread has made up a key component of human nutrition since the beginning of agriculture.
These include drying, freezing, heating, milling, pressing, packaging, refrigeration, and irradiation.
[39] Humans can also obtain energy from ethanol, which is both a food and a drug, but it provides relatively few essential nutrients and is associated with nutritional deficiencies and other health risks.
[40] In humans, poor nutrition can cause deficiency-related diseases, such as blindness, anemia, scurvy, preterm birth, stillbirth and cretinism,[41] or nutrient-excess conditions, such as obesity[42] and metabolic syndrome.
[43] Other conditions possibly affected by nutrition disorders include cardiovascular diseases,[44] diabetes,[45][46] and osteoporosis.
Large-breed puppies are susceptible to overnutrition, as small-breed dog food is more energy dense than they can absorb.
Carbon, hydrogen, oxygen, nitrogen, and sulfur are essential nutrients that make up organic material in a plant and allow enzymic processes.
Other nutrients used by plants are potassium, sodium, calcium, magnesium, manganese, chlorine, iron, copper, zinc, and molybdenum.
[49] Plants uptake essential elements from the soil through their roots and from the air (consisting of mainly nitrogen and oxygen) through their leaves.
Most fungi absorb matter through the root-like mycelium, which grows through the organism's source of nutrients and can extend indefinitely.
The fungus excretes extracellular enzymes to break down surrounding matter and then absorbs the nutrients through the cell wall.
[53] Protists include all eukaryotes that are not animals, plants, or fungi, resulting in great diversity between them.
[55] Prokaryotes, including bacteria and archaea, vary greatly in how they obtain nutrients across nutritional groups.
Prokaryotes can only transport soluble compounds across their cell envelopes, but they can break down chemical components around them.
Some lithotrophic prokaryotes are extremophiles that can survive in nutrient-deprived environments by breaking down inorganic matter.
[56] Phototrophic prokaryotes, such as cyanobacteria and Chloroflexia, can engage in photosynthesis to obtain energy from sunlight.
Groups of predatory prokaryotes may forgo attachment by collectively producing hydrolytic enzymes.
