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Mom Always Said to Eat Your Veggies; Now Scientists Are Finding Out Why.

Phytochemicals in vegetables can prevent anywhere from 20% to 60% of cancers, and broccoli sprouts seem to be the best -- working even better than mature plants.

Since the mid-1970s, dietary advice on preventing cancer has stressed fruit and vegetable consumption. But recent research makes them look even better as cancer fighters, Donald Schlimme of the University of Maryland told the Scientific Advisory Council of the World Food Logistics Organization (WFLO) during its annual meeting in May, held in Boca Raton, Florida.

"Researchers have recently estimated that plant-based diets prevent 20% to 60% of all cases of cancer," Schlimme said. "The scientific literature since 1990 abounds with the results of ever more sophisticated research exploring the biochemical basis for the health benefits of dietary fruit, grain and vegetable materials."

Indeed, humanity seems to be at the dawn of a second golden age of nutrition, he said -- the age of phytochemicals for disease prevention. Phytochemicals are biologically active chemicals found in a wide array of food plants in rather small quantities (typically less than 0.1%) which are not metabolized as "nutrients" per se, and contribute no caloric, mineral or vitamin benefit in the diet of humans.

Cruciferous vegetables of genus Brassica -- broccoli, cabbage, cauliflower, and brussels sprouts, among others -- have been recommended for cancer prevention for nearly 20 years. Why? It has long been known that they contain little fat, are low in calories, and are sources of vitamins, minerals, and fiber -- all aspects associated with healthy eating. But now it has been shown that they also contain a significant number of phytochemicals, some of which have been shown to protect against cancer.

"Several enzymes oxidize, reduce, or hydrolyze metabolites, carcinogens and other chemicals -- these are known as `phase 1' enzymes," Schlimme explained. "Other enzymes conjugate or otherwise affect these metabolites, carcinogens, and other chemicals, thereby increasing their polarity and excretability -- these are known as `phase 2' enzymes. Phase 1 enzymes can activate or inactivate carcinogens, depending on experimental conditions. Phase 2 enzymes are more likely to detoxify them."

A series of studies at Johns Hopkins University demonstrate that Brassica vegetables are rich sources of phase 2 inducers and identify isothiocyanate sulforaphane as the principal phase 2 inducer in broccoli extracts. They also show that sulforaphane is a dose-related inhibitor of carcinogen-induced breast tumors in rats. Further studies show that broccoli sprouts contain ten to 100 times as much phase 2 inducer activity of mature broccoli plants and are more efficient inhibitors of rat tumorigenesis.

Researchers have concluded that small amounts of cruciferous vegetable sprouts may be just as good against cancer as larger amounts of mature plants of the same variety. Sulforaphane is derived from a glucosinolate precursor, glucoraphanin, by the activity of myrosinase. These studies leave no doubt that sulforaphane (derived from biogenesis of glucoraphanin in broccoli) does indeed induce phase 2 enzymes which inhibit carcinogenesis.

There is general agreement that phytochemicals, in addition to essential vitamins and minerals in fruits, grains and vegetables play a role in retarding, and perhaps even preventing the onset of chronic disease. But there is still much research to be done to determine how these effects are achieved and the nature of interactions and synergies among phytochemicals, vitamins and minerals, remain incomplete.

"As our knowledge of phytochemicals increases, mankind will increasingly be knowledgeable and aware of the substantial health benefits that accrue to consumption of plant foods," Schlimme declared.

In 1994 the National Cancer Institute in the United States launched the "Five a Day Program" to promote consumption of five or more servings of fruits and vegetables daily. A study in 1995 revealed that only 23% of the US population regularly consumed that much. Recent data suggest that the average American eats slightly more than two half-cup servings of vegetables (other than potatoes) daily, and that at least 10% consume less than one daily serving of any vegetable whatever.

"Educational campaigns to encourage fruit and vegetable consumption have, to date, achieved rather limited success," Schlimme lamented "But a greater range of policies and programs targeted to food producers as well as to consumers could prove more effective in raising consumption levels."

RELATED ARTICLE: US Consumers Nix GM Foods, And Nearly All Want Labeling

Some 52% of US consumers think that genetically modified (GM) foods are unsafe, according to a poll by ABC TV News. A little more than a third think GM foods are okay, and 13% are uncertain. Support was nearly unanimous -- 93% -- for mandatory labeling of GM foods, and 57% said they'd be less likely to buy products so labeled.
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Title Annotation:vegetable found to prevent cancer
Comment:Mom Always Said to Eat Your Veggies; Now Scientists Are Finding Out Why.(vegetable found to prevent cancer)
Publication:Quick Frozen Foods International
Article Type:Brief Article
Geographic Code:1USA
Date:Jul 1, 2001
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