is an antinutrient that interferes with the absorption of minerals from the diet.]]
are natural or synthetic compounds that interfere with the absorption of nutrient
s. Oxford Dictionary of Biochemistry and Molecular Biology
. Oxford University Press, 2006. . Nutrition studies focus on those antinutrients commonly found in food sources and beverages.
are substances that inhibit the actions of trypsin
and other proteases in the gut, preventing the digestion and subsequent absorption of protein. For example, Bowman–Birk trypsin inhibitor
is found in soybeans.
inhibitors interfere with enzymes, such as human pancreatic lipase
, that catalyze the hydrolysis of some lipid
s, including fats. For example, the anti-obesity drug orlistat
causes a percentage of fat to pass through the digestive tract undigested.
inhibitors prevent the action of enzymes that break the glycosidic bond
s of starch
es and other complex carbohydrate
s, preventing the release of simple sugars and absorption by the body. Amylase inhibitors, like lipase inhibitors, have been used as a diet aid and obesity treatment. Amylase inhibitors are present in many types of beans; commercially available amylase inhibitors are extracted from white kidney beans.
has a strong binding affinity to minerals such as calcium
, and zinc
. This results in precipitation, making the minerals unavailable for absorption in the intestines. Phytic acids are common in the hulls of nuts, seeds and grains.
s are present in many plants, particularly in members of the spinach
family. Oxalates bind to calcium
and prevent its absorption in the human body.
s prevent the uptake of iodine
, affecting the function of the thyroid and thus are considered goitrogen
s. They are found in broccoli, brussel sprouts, cabbage and cauliflower.
Excessive intake of required nutrients can also result in them having an anti-nutrient action. Excessive intake of fiber
can reduce the transit time through the intestines to such a degree that other nutrients cannot be absorbed. Because calcium, iron, zinc and magnesium share the same transporter within the intestine, excessive consumption of one of these minerals can lead to saturation of the transport system and reduced absorption of the other minerals.
can also be antinutrients, such as the trypsin inhibitor
s and lectin
s found in legume
s. These enzyme inhibitor
s interfere with digestion.
Another particularly widespread form of antinutrients are the flavonoid
s, which are a group of polyphenol
ic compounds that include tannin
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.
s in plants may serve as anti-feedant
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
. The possibility now exists to eliminate antinutrients entirely using genetic engineering
; but, since these compounds may also have beneficial effects, such genetic modifications could make the foods more nutritious but not improve people's health.
Many traditional methods of food preparation such as fermentation
, and malting
increase the nutritive quality of plant foods through reducing certain antinutrients such as phytic acid, polyphenols, and oxalic acid. 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
to produce cassava flour: this fermentation reduces the levels of both toxins and antinutrients in the tuber.