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Phytochemical 1

Phytochemical

Phytochemicals, chemical compounds that occur naturally in plants (phyto means "plant" in Greek), are responsible

for color and organoleptic properties, such as the deep purple of blueberries and smell of garlic. The term is

generally used to refer to those chemicals that may have biological significance, for example antioxidants, but are

not established as essential nutrients.[1] Scientists estimate[citation needed] that there may be as many as 10,000

different phytochemicals having the potential to affect diseases such as cancer, stroke or metabolic syndrome.

Phytochemicals as candidate nutrients

Without specific knowledge of their cellular actions or mechanisms, phytochemicals have been considered as drugs

for millennia. For example, Hippocrates may have prescribed willow tree leaves to abate fever. Salicin, having

anti-inflammatory and pain-relieving properties, was originally extracted from the bark of the white willow tree and

later synthetically produced became the staple over-the-counter drug aspirin.

There is evidence from laboratory studies that phytochemicals in fruits and vegetables may reduce the risk of cancer,

possibly due to dietary fibers, polyphenol antioxidants and anti-inflammatory effects. Specific phytochemicals, such

as fermentable dietary fibers, are allowed limited health claims by the US Food and Drug Administration (FDA).[1]

An important cancer drug, Taxol (paclitaxel), is a phytochemical initially extracted and purified from the Pacific yew

tree.

Some phytochemicals with physiological properties may be elements rather than complex organic

molecules.Sometimes they can be harmful and sometimes they can be very helpful, as far as concerned they are

responsible for the color in vegetables or fruits. Abundant in many fruits and vegetables, selenium, for example, is

involved with major metabolic pathways, including thyroid hormone metabolism and immune function.[2]

Particularly, it is an essential nutrient and cofactor for the enzymatic synthesis of glutathione, an endogenous

antioxidant.[3]

Clinical trials and health claim status

There are currently many phytochemicals in clinical trials for a variety of diseases. Lycopene from tomatoes, for

example, has been tested in human studies for cardiovascular diseases and prostate cancer. These studies, however,

did not attain sufficient scientific agreement to conclude an effect on any disease.[4]

The FDA position reads:

"Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato

sauce a week may reduce the risk of prostate cancer. The United States Food and Drug Administration concludes

that there is little scientific evidence supporting this claim."

Likewise, although lutein and zeaxanthin are suspected to inhibit macular degeneration and cataracts, there was

insufficient scientific evidence from clinical trials for such specific effects or health claims.[5][]

http://en.wikipedia.org/w/index.php?title=Macular_degenerationhttp://en.wikipedia.org/w/index.php?title=Zeaxanthinhttp://en.wikipedia.org/w/index.php?title=Luteinhttp://en.wikipedia.org/w/index.php?title=Food_and_Drug_Administration_%28United_States%29http://en.wikipedia.org/w/index.php?title=Prostate_cancerhttp://en.wikipedia.org/w/index.php?title=Lycopenehttp://en.wikipedia.org/w/index.php?title=Clinical_trialhttp://en.wikipedia.org/w/index.php?title=Antioxidanthttp://en.wikipedia.org/w/index.php?title=Endogenoushttp://en.wikipedia.org/w/index.php?title=Glutathionehttp://en.wikipedia.org/w/index.php?title=Cofactor_%28biochemistry%29http://en.wikipedia.org/w/index.php?title=Essential_nutrienthttp://en.wikipedia.org/w/index.php?title=Immunehttp://en.wikipedia.org/w/index.php?title=Thyroid_hormonehttp://en.wikipedia.org/w/index.php?title=Seleniumhttp://en.wikipedia.org/w/index.php?title=Physiologicalhttp://en.wikipedia.org/w/index.php?title=Taxus_brevifoliahttp://en.wikipedia.org/w/index.php?title=Taxus_brevifoliahttp://en.wikipedia.org/w/index.php?title=Paclitaxelhttp://en.wikipedia.org/w/index.php?title=Taxolhttp://en.wikipedia.org/w/index.php?title=Dietary_fiberhttp://en.wikipedia.org/w/index.php?title=Fermentation_%28biochemistry%29http://en.wikipedia.org/w/index.php?title=Inflammationhttp://en.wikipedia.org/w/index.php?title=Polyphenol_antioxidanthttp://en.wikipedia.org/w/index.php?title=Dietary_fiberhttp://en.wikipedia.org/w/index.php?title=Cancerhttp://en.wikipedia.org/w/index.php?title=Aspirinhttp://en.wikipedia.org/w/index.php?title=Anti-inflammatoryhttp://en.wikipedia.org/w/index.php?title=Salicinhttp://en.wikipedia.org/w/index.php?title=Willow_treehttp://en.wikipedia.org/w/index.php?title=Hippocrateshttp://en.wikipedia.org/w/index.php?title=Metabolic_syndromehttp://en.wikipedia.org/w/index.php?title=Strokehttp://en.wikipedia.org/w/index.php?title=Cancerhttp://en.wikipedia.org/wiki/Citation_neededhttp://en.wikipedia.org/w/index.php?title=Antioxidantshttp://en.wikipedia.org/w/index.php?title=Organoleptic

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Phytochemical 2

Food processing and phytochemicals

Phytochemicals in freshly harvested plant foods may be destroyed or removed by modern processing techniques,

including cooking.[6]

For this reason, industrially processed foods likely contain fewer phytochemicals and may thus

be less beneficial than unprocessed foods. Absence or deficiency of phytochemicals in processed foods may

contribute to increased risk of preventable diseases.[7][8]

A converse example may exist in which lycopene, a phytochemical present in tomatoes, is either unchanged in

content[9]

or made more concentrated[10]

by processing to juice or paste, maintaining good levels for bioavailability.

References

[1] US FDA, Guidance for Industry: Evidence-Based Review System for the Scientific Evaluation of Health Claims (http://www.fda.gov/

Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/ucm073332. htm)

[4] Qualified Health Claims Subject to Enforcement Discretion, Docket No. 2004Q-0201 (http://www.fda.gov/Food/LabelingNutrition/

LabelClaims/QualifiedHealthClaims/ucm073992. htm), US Food and Drug Administration

[5] US FDA, Qualified Health Claims: Letter of Denial - Xangold Lutein Esters, Lutein, or Zeaxanthin and Reduced Risk of Age-related Macular

Degeneration or Cataract Formation (Docket No. 2004Q-0180) (http://www.cfsan.fda. gov/~dms/qhclutei.html)

[6] Cooking and nutrient loss (http://whfoods. org/genpage. php?tname=george& dbid=61), World's Healthiest Foods

Further reading

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. / Gonzlez-Aguilar, G.A. (eds.)Fruit and Vegetable Phytochemicals:

Chemistry, Nutritional Value and Stability. 2010. Wiley-Blackwell. ISBN 978-0-8138-0320-3

External links

Phytochemical Database (http://www.pl. barc.usda.gov/home.cfm) - United States Department of Agriculture

Phytochemicals at LPI (http://lpi.oregonstate. edu/infocenter/phytochemicals.html) - Linus Pauling Institute at

Oregon State University

http://lpi.oregonstate.edu/infocenter/phytochemicals.htmlhttp://www.pl.barc.usda.gov/home.cfmhttp://whfoods.org/genpage.php?tname=george&dbid=61http://www.cfsan.fda.gov/~dms/qhclutei.htmlhttp://en.wikipedia.org/w/index.php?title=Food_and_Drug_Administrationhttp://www.fda.gov/Food/LabelingNutrition/LabelClaims/QualifiedHealthClaims/ucm073992.htmhttp://www.fda.gov/Food/LabelingNutrition/LabelClaims/QualifiedHealthClaims/ucm073992.htmhttp://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/ucm073332.htmhttp://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodLabelingNutrition/ucm073332.htmhttp://en.wikipedia.org/w/index.php?title=Bioavailabilityhttp://en.wikipedia.org/w/index.php?title=Tomato_pastehttp://en.wikipedia.org/w/index.php?title=Tomato_juicehttp://en.wikipedia.org/w/index.php?title=Concentrationhttp://en.wikipedia.org/w/index.php?title=Tomatohttp://en.wikipedia.org/w/index.php?title=Lycopene

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