Antinutrients are natural or synthetic compounds that interfere with the absorption of
nutrients.[1] Nutrition studies focus on antinutrients commonly found in food sources and beverages. Antinutrients may take the form of drugs, chemicals that naturally occur in food sources,
proteins, or overconsumption of nutrients themselves. Antinutrients may act by binding to vitamins and minerals, preventing their uptake, or inhibiting enzymes.
Throughout history, humans have bred crops to reduce antinutrients, and cooking processes have developed to remove them from raw food materials and increase nutrient
bioavailability, notably in staple foods such as
cassava.
Lipase inhibitors interfere with enzymes, such as
human pancreatic lipase, that catalyze the hydrolysis of some
lipids, including fats. For example, the anti-obesity drug
orlistat causes a percentage of fat to pass through the digestive tract undigested.[9]
Amylase inhibitors prevent the action of enzymes that break the
glycosidic bonds of
starches and other complex
carbohydrates, preventing the release of simple sugars and absorption by the body. Like lipase inhibitors, they have been used as a diet aid and obesity treatment. They are present in many types of beans; commercially available amylase inhibitors are extracted from white
kidney beans.[10]
Other
Excessive intake of required nutrients can also result in them having an anti-nutrient action. Excessive intake of
dietary fiber can reduce the transit time through the intestines to such a degree that other nutrients cannot be absorbed. However, this effect is often not seen in practice and reduction of absorbed minerals can be attributed mainly to the phytic acids in fibrous food.[11][12] Foods high in
calcium eaten simultaneously with foods containing
iron can decrease the absorption of iron via an unclear mechanism involving iron
transport protein h
DMT1, which calcium can inhibit.[13]
Avidin is an antinutrient found in active form in raw
egg whites. It binds very tightly to
biotin (
vitamin B7)[14] and can cause deficiency of B7 in animals[15] and, in extreme cases, in humans.[16]
A widespread form of antinutrients, the
flavonoids, are a group of
polyphenolic compounds that include
tannins.[17] These compounds
chelate metals such as iron and zinc and reduce the absorption of these nutrients,[18] and they also inhibit digestive enzymes and may also precipitate proteins.[19]
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.[23] 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.[24]
Many traditional methods of food preparation such as
germination,
cooking,
fermentation, and
malting increase the nutritive quality of plant foods through reducing certain antinutrients such as phytic acid, polyphenols, and oxalic acid.[25] Such processing methods are widely used in societies where cereals and legumes form a major part of the diet.[26][27] 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.[28]
^Ekholm P, Virkki L, Ylinen M, Johansson L (Feb 2003). "The effect of phytic acid and some natural chelating agents on the solubility of mineral elements in oat bran". Food Chemistry. 80 (2): 165–70.
doi:
10.1016/S0308-8146(02)00249-2.
^Cheryan M (1980). "Phytic acid interactions in food systems". Critical Reviews in Food Science and Nutrition. 13 (4): 297–335.
doi:
10.1080/10408398009527293.
PMID7002470.
^Preuss HG (June 2009). "Bean amylase inhibitor and other carbohydrate absorption blockers: effects on diabesity and general health". Journal of the American College of Nutrition. 28 (3): 266–76.
doi:
10.1080/07315724.2009.10719781.
PMID20150600.
S2CID20066629.
^"Fiber". Linus Pauling Institute. 2014-04-28.
Archived from the original on 2018-04-14. Retrieved 2018-04-15.
^Baugh CM, Malone JH, Butterworth CE (February 1968). "Human biotin deficiency. A case history of biotin deficiency induced by raw egg consumption in a cirrhotic patient". The American Journal of Clinical Nutrition. 21 (2): 173–82.
doi:
10.1093/ajcn/21.2.173.
PMID5642891.
^Sparg SG, Light ME, van Staden J (October 2004). "Biological activities and distribution of plant saponins". Journal of Ethnopharmacology. 94 (2–3): 219–43.
doi:
10.1016/j.jep.2004.05.016.
PMID15325725.
^Chavan JK, Kadam SS (1989). "Nutritional improvement of cereals by fermentation". Critical Reviews in Food Science and Nutrition. 28 (5): 349–400.
doi:
10.1080/10408398909527507.
PMID2692608.
^Phillips RD (November 1993). "Starchy legumes in human nutrition, health and culture". Plant Foods for Human Nutrition. 44 (3): 195–211.
doi:
10.1007/BF01088314.
PMID8295859.
S2CID24735125.
^Oboh G, Oladunmoye MK (2007). "Biochemical changes in micro-fungi fermented cassava flour produced from low- and medium-cyanide variety of cassava tubers". Nutrition and Health. 18 (4): 355–67.
doi:
10.1177/026010600701800405.
PMID18087867.
S2CID25650282.
Further reading
Shahidi, Fereidoon (1997). Antinutrients and phytochemicals in food. Columbus, OH: American Chemical Society.
ISBN0-8412-3498-1.