Antinutrient

Phytic acid (deprotonated phytate anion in the picture) is an antinutrient that interferes with the absorption of minerals from the diet.

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.

Mechanisms

Preventing mineral uptake

Phytic acid has a strong binding affinity to minerals such as calcium, magnesium, iron, copper, and zinc. This results in precipitation, making the minerals unavailable for absorption in the intestines.[2][3] Phytic acids are common in the hulls of nuts, seeds, and grains and of great importance in agriculture, animal nutrition, and in eutrophication, due to the mineral chelation and bound phosphates released into the environment. Without the need to use milling to reduce phytate (including nutrient),[4] the amount of phytic acid is commonly reduced in animal feeds by adding histidine acid phosphate type of phytases to them.[5]

Oxalic acid and oxalates are present in many plants and in significant amounts particularly in rhubarb, tea, spinach, parsley, and purslane. Oxalates bind to calcium, magnesium and iron, preventing their absorption in the human body.[6]

Glucosinolates prevent the uptake of iodine, affecting the function of the thyroid and thus are considered goitrogens. They are found in plants such as broccoli, Brussels sprouts, cabbage, mustard greens, radishes, and cauliflower.[6]

Enzyme inhibition

Protease inhibitors are substances that inhibit the actions of trypsin, pepsin, and other proteases in the gut, preventing the digestion and subsequent absorption of protein. For example, Bowman–Birk trypsin inhibitor is found in soybeans.[7] Some trypsin inhibitors and lectins are found in legumes and interfere with digestion.[8]

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]

Hypoglycin A, which is contained in lychees and ackee fruit, blocks the fatty acid metabolism, so that the body uses its glycogen deposits for energy, which can cause hypoglycemia, when these fruit are eaten in large quantities or as the sole diet.

Coprine found in some edible mushrooms, for example the common inkcap, inhibits the aldehyde dehydrogenase, which is a part of the alcohol digestive system. This can cause a buildup of the toxic acetaldehyde. Therefore, mushrooms containing coprine should never be consumed together with alcoholic beverages.

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 hDMT1, 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]

Saponins in plants may act like antifeedants[20][21] and can be classified as antinutrients.[22]

Occurrence and removal

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]

See also

References

  1. ^ Cammack, Richard; Atwood, Teresa; Campbell, Peter; Parish, Howard; Smith, Anthony; Vella, Frank; Stirling, John, eds. (2006). "Aa". Oxford dictionary of biochemistry and molecular biology. Cammack, Richard (Rev. ed.). Oxford: Oxford University Press. p. 47. doi:10.1093/acref/9780198529170.001.0001. ISBN 9780198529170. OCLC 65467611.
  2. ^ 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.
  3. ^ Cheryan M (1980). "Phytic acid interactions in food systems". Critical Reviews in Food Science and Nutrition. 13 (4): 297–335. doi:10.1080/10408398009527293. PMID 7002470.
  4. ^ Bohn L, Meyer AS, Rasmussen SK (March 2008). "Phytate: impact on environment and human nutrition. A challenge for molecular breeding". Journal of Zhejiang University Science B. 9 (3): 165–91. doi:10.1631/jzus.B0710640. PMC 2266880. PMID 18357620.
  5. ^ Kumar V, Singh G, Verma AK, Agrawal S (2012). "In silico characterization of histidine Acid phytase sequences". Enzyme Research. 2012: 845465. doi:10.1155/2012/845465. PMC 3523131. PMID 23304454.
  6. ^ a b Dolan LC, Matulka RA, Burdock GA (September 2010). "Naturally occurring food toxins". Toxins. 2 (9): 2289–332. doi:10.3390/toxins2092289. PMC 3153292. PMID 22069686.
  7. ^ Tan-Wilson AL, Chen JC, Duggan MC, Chapman C, Obach RS, Wilson KA (1987). "Soybean Bowman-Birk trypsin isoinhibitors: classification and report of a glycine-rich trypsin inhibitor class". J. Agric. Food Chem. 35 (6): 974. doi:10.1021/jf00078a028.
  8. ^ Gilani GS, Cockell KA, Sepehr E (May 2005). "Effects of antinutritional factors on protein digestibility and amino acid availability in foods". Journal of AOAC International. 88 (3): 967–87. doi:10.1093/jaoac/88.3.967. PMID 16001874.
  9. ^ Heck AM, Yanovski JA, Calis KA (March 2000). "Orlistat, a new lipase inhibitor for the management of obesity". Pharmacotherapy. 20 (3): 270–9. doi:10.1592/phco.20.4.270.34882. PMC 6145169. PMID 10730683.
  10. ^ 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. PMID 20150600. S2CID 20066629.
  11. ^ "Fiber". Linus Pauling Institute. 2014-04-28. Archived from the original on 2018-04-14. Retrieved 2018-04-15.
  12. ^ Coudray C, Demigné C, Rayssiguier Y (January 2003). "Effects of dietary fibers on magnesium absorption in animals and humans". The Journal of Nutrition. 133 (1): 1–4. doi:10.1093/jn/133.1.1. PMID 12514257.
  13. ^ Scheers N (March 2013). "Regulatory effects of Cu, Zn, and Ca on Fe absorption: the intricate play between nutrient transporters". Nutrients. 5 (3): 957–70. doi:10.3390/nu5030957. PMC 3705329. PMID 23519291.
  14. ^ Miranda JM, Anton X, Redondo-Valbuena C, Roca-Saavedra P, Rodriguez JA, Lamas A, Franco CM, Cepeda A (January 2015). "Egg and egg-derived foods: effects on human health and use as functional foods". Nutrients. 7 (1): 706–29. doi:10.3390/nu7010706. PMC 4303863. PMID 25608941.
  15. ^ Poissonnier LA, Simpson SJ, Dussutour A (2014-11-13). "Observations of the "egg white injury" in ants". PLOS ONE. 9 (11): e112801. Bibcode:2014PLoSO...9k2801P. doi:10.1371/journal.pone.0112801. PMC 4231089. PMID 25392989.
  16. ^ 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. PMID 5642891.
  17. ^ Beecher GR (October 2003). "Overview of dietary flavonoids: nomenclature, occurrence and intake". The Journal of Nutrition. 133 (10): 3248S – 3254S. doi:10.1093/jn/133.10.3248S. PMID 14519822.
  18. ^ Karamać M (December 2009). "Chelation of Cu(II), Zn(II), and Fe(II) by tannin constituents of selected edible nuts". International Journal of Molecular Sciences. 10 (12): 5485–97. doi:10.3390/ijms10125485. PMC 2802006. PMID 20054482.
  19. ^ Adamczyk B, Simon J, Kitunen V, Adamczyk S, Smolander A (October 2017). "Tannins and Their Complex Interaction with Different Organic Nitrogen Compounds and Enzymes: Old Paradigms versus Recent Advances". ChemistryOpen. 6 (5): 610–614. doi:10.1002/open.201700113. PMC 5641916. PMID 29046854.
  20. ^ Moses T, Papadopoulou KK, Osbourn A (2014). "Metabolic and functional diversity of saponins, biosynthetic intermediates and semi-synthetic derivatives". Critical Reviews in Biochemistry and Molecular Biology. 49 (6): 439–62. doi:10.3109/10409238.2014.953628. PMC 4266039. PMID 25286183.
  21. ^ 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. PMID 15325725.
  22. ^ Difo VH, Onyike E, Ameh DA, Njoku GC, Ndidi US (September 2015). "Changes in nutrient and antinutrient composition of Vigna racemosa flour in open and controlled fermentation". Journal of Food Science and Technology. 52 (9): 6043–8. doi:10.1007/s13197-014-1637-7. PMC 4554638. PMID 26345026.
  23. ^ GEO-PIE Project. "Plant Toxins and Antinutrients". Cornell University. Archived from the original on June 12, 2008.
  24. ^ Welch RM, Graham RD (February 2004). "Breeding for micronutrients in staple food crops from a human nutrition perspective". Journal of Experimental Botany. 55 (396): 353–64. doi:10.1093/jxb/erh064. PMID 14739261.
  25. ^ Hotz C, Gibson RS (April 2007). "Traditional food-processing and preparation practices to enhance the bioavailability of micronutrients in plant-based diets". The Journal of Nutrition. 137 (4): 1097–100. doi:10.1093/jn/137.4.1097. PMID 17374686.
  26. ^ 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. PMID 2692608.
  27. ^ 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. PMID 8295859. S2CID 24735125.
  28. ^ 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. PMID 18087867. S2CID 25650282.

Further reading

  • Shahidi, Fereidoon (1997). Antinutrients and phytochemicals in food. Columbus, OH: American Chemical Society. ISBN 0-8412-3498-1.