Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrient

Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

s. Nutrition studies focus on those antinutrients commonly found in food sources and beverages.

One common example is phytic acid

Phytic acid

Phytic acid is the principal storage form of phosphorus in many plant tissues, especially bran and seeds. Phytate is not digestible to humans or nonruminant animals, however, so it is not a source of either inositol or phosphate if eaten directly...

, which forms insoluble complexes with calcium, zinc, iron and copper. Proteins can also be antinutrients, such as the trypsin inhibitor

Trypsin inhibitor

Trypsin inhibitors are chemicals that reduce the availability of trypsin, an enzyme essential to nutrition of many animals, including humans.There are four commercial sources of trypsin inhibitors....

s and lectin

Lectin

Lectins are sugar-binding proteins that are highly specific for their sugar moieties. They play a role in biological recognition phenomena involving cells and proteins. For example, some viruses use lectins to attach themselves to the cells of the host organism during infection...

s found in legumes. These enzyme inhibitor

Enzyme inhibitor

An enzyme inhibitor is a molecule that binds to enzymes and decreases their activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used as herbicides and pesticides...

s interfere with digestion. Another particularly widespread form of antinutrients are the flavonoid

Flavonoid

Flavonoids , are a class of plant secondary metabolites....

s, which are a group of polyphenol

Polyphenol

Polyphenols are a structural class of natural, synthetic, and semisynthetic organic chemicals characterized by the presence of large multiples of phenol structural units...

ic compounds that include tannin

Tannin

A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...

s. These compounds chelate metals such as iron and zinc and reduce the absorption of these nutrients, but they also inhibit digestive enzymes and may also precipitate proteins. However, polyphenols such as tannins have anticancer properties, so drinks such as green tea

Green tea

Green tea is made solely from the leaves of Camellia sinensis that have undergone minimal oxidation during processing. Green tea originates from China and has become associated with many cultures throughout Asia. It has recently become more widespread in the West, where black tea is traditionally...

 that contain large amounts of these compounds might be good for the health of some people despite their antinutrient properties.

Antinutrients are found at some level in almost all foods for a variety of reasons. However, their levels are reduced in modern crops, probably as an outcome of the process of domestication

Domestication

Domestication or taming is the process whereby a population of animals or plants, through a process of selection, becomes accustomed to human provision and control. In the Convention on Biological Diversity a domesticated species is defined as a 'species in which the evolutionary process has been...

. Nevertheless, the large fraction of modern diets that come from a few crops, particularly cereals, has raised concerns about the effects of the antinutrients in these crops on human health. The possibility now exists to eliminate antinutrients entirely using genetic engineering

Genetic engineering

Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...

; but, since these compounds may also have beneficial effects (such polyphenols reduce the risk of cancer

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, heart disease

Heart disease

Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

 or diabetes), such genetic modifications could make the foods more nutritious but not improve people's health.

Many traditional methods of food preparation such as fermentation

Fermentation (food)

Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. Fermentation in simple terms is the chemical conversion of sugars into ethanol...

, cooking

Cooking

Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...

, and malting increase the nutritive quality of plant foods through reducing certain antinutrients such as phytic acid, polyphenols, and oxalic acid

Oxalic acid

Oxalic acid is an organic compound with the formula H2C2O4. This colourless solid is a dicarboxylic acid. In terms of acid strength, it is about 3,000 times stronger than acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate , is a chelating agent for metal cations...

. Such processing methods are widely-used in societies where cereals and legumes form a major part of the diet. An important example of such processing is the fermentation of cassava

Cassava

Cassava , also called yuca or manioc, a woody shrub of the Euphorbiaceae native to South America, is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates...

to produce cassava flour: this fermentation reduces the levels of both toxins and antinutrients in the tuber.