Phytochemical

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Phytochemicals are naturally occurring chemical compounds in plants.[1] Phyto means "plant" in Greek. They are responsible for a plant's organoleptic properties, such as the deep purple of blueberries, or the smell of garlic. Some phytochemicals have been considered as possible drugs for millennia, while others, like carotenoids, are significant as provitamin compounds. However, with the exception of dietary fiber, phytochemicals are not established as essential nutrients. There may be as many as 4,000 different compounds in plants that are regarded as phytochemicals with potential for biological activity.[2]

Phytochemicals as medicines and nutrients[edit]

Without specific knowledge of their cellular actions or mechanisms, phytochemicals have been considered possible drugs for millennia. For example, salicin, having anti-inflammatory and pain-relieving properties, was originally extracted from the bark of the white willow tree and later synthetically produced to become the common, over-the-counter drug, aspirin.[3][4]

The biological or nutritional effects of most phytochemicals are unknown.[1] The carotenoids, beta-carotene, alpha-carotene, and beta-cryptoxanthin, however, are well-established as provitamin A compounds essential for normal growth and development, immune system function, and vision.[5] Other carotenoid phytochemicals, such as lycopene, lutein and zeaxanthin, are not yet fully understood for their possible nutritional or biological effects.[5]

Considerable research has been conducted on the possible properties of phytochemicals like polyphenols, but there is insufficient evidence to date that they have any effect from dietary intake or use as dietary supplements.[1][6]

Health guidance[edit]

There is only limited scientific evidence that phytochemicals have biological activity or nutritional value.[1] Nondigestible dietary fibers from plant foods, often considered as a phytochemical,[1] are now generally regarded as a nutrient group having approved health claims for reducing the risk of some types of cancer[7] and coronary heart disease.[8]

According to the American Cancer Society, "no evidence has shown that phytochemicals taken as supplements are as good for your long-term health as the vegetables, fruits, beans, and grains from which they are extracted."[6]

Effects of food processing[edit]

Phytochemicals in freshly harvested plant foods may be degraded by processing techniques, including cooking.[9][10][11] The main cause of phytochemical loss from cooking is thermal decomposition.[11]

A converse exists in the case of carotenoids, such as lycopene present in tomatoes, which may remain stable or increase in content from cooking due to liberation from cellular membranes in the cooked food.[12] Food processing techniques like mechanical processing can also free carotenoids and other phytochemicals from the food matrix, increasing dietary intake.[11][13]

See also[edit]

References[edit]

  1. ^ a b c d e "Phytochemicals". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon. 2014. Retrieved 18 June 2014. 
  2. ^ "Fruits and Veggies, More Matters. What are phytochemicals?". Produce for Better Health Foundation. 2014. Retrieved 18 June 2014. 
  3. ^ Sneader, W. (2000). "The discovery of aspirin: A reappraisal". BMJ (Clinical research ed.). 321 (7276): 1591–1594. doi:10.1136/bmj.321.7276.1591. PMC 1119266Freely accessible. PMID 11124191. 
  4. ^ Landau E (22 Dec 2010). "From a tree, a 'miracle' called aspirin". CNN. Retrieved 18 June 2014. 
  5. ^ a b "Carotenoids". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, Oregon. 2017. Retrieved 8 January 2017. 
  6. ^ a b "Common questions about diet and cancer". American Cancer Society. 5 February 2016. Retrieved 8 January 2017. 
  7. ^ "Health claims: fiber-containing grain products, fruits, and vegetables and cancer; Title 21: Food and Drugs, Subpart E, 101.76". U.S. Food and Drug Administration. 5 January 2017. Retrieved 8 January 2017. 
  8. ^ "Health claims: Soluble fiber from certain foods and risk of coronary heart disease (CHD); Title 21: Food and Drugs, Subpart E, 101.81". U.S. Food and Drug Administration. 5 January 2017. Retrieved 8 January 2017. 
  9. ^ Bongoni, R; Steenbekkers, L.P.A; Verkerk, R; van Boekel, M.A.J.S; Dekker, M (2013). "Studying consumer behaviour related to the quality of food: A case on vegetable preparation affecting sensory and health attributes". Trends in Food Science & Technology. 33 (2): 139–145. doi:10.1016/j.tifs.2013.08.004. 
  10. ^ Bongoni, R; Verkerk, R; Steenbekkers, B; Dekker, M; Stieger (2014). "Evaluation of Different Cooking Conditions on Broccoli (Brassica oleracea var. italica) to Improve the Nutritional Value and Consumer Acceptance.". Plant foods for human nutrition. 69: 228–234. doi:10.1007/s11130-014-0420-2. PMID 24853375. 
  11. ^ a b c Palermo, M; Pellegrini, N; Fogliano, V (2014). "The effect of cooking on the phytochemical content of vegetables". Journal of the Science of Food and Agriculture. 94 (6): 1057–70. doi:10.1002/jsfa.6478. PMID 24227349. 
  12. ^ Dewanto, V; Wu, X; Adom, KK; Liu, RH (2002). "Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity". Journal of Agricultural and Food Chemistry. 50 (10): 3010–4. doi:10.1021/jf0115589. PMID 11982434. 
  13. ^ Hotz, C; Gibson, R. S. (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. PMID 17374686. 

Further reading[edit]

  • Higdon, J. An Evidence – Based Approach to Dietary Phytochemicals. 2007. Thieme. ISBN 978-1-58890-408-9.
  • Rosa, L.A. de la / Alvarez-Parrilla, E. / González-Aguilar, G.A. (eds.) Fruit and Vegetable Phytochemicals: Chemistry, Nutritional Value and Stability. 2010. Wiley-Blackwell. ISBN 978-0-8138-0320-3.

External links[edit]