Grapefruit juice boosts cancer fighting liver enzymes
All news for March 2005
All news for February 2005
03/10/2005 - Soft drink beverage makers will welcome further evidence supporting the health promoting compounds in grapefruits, with a recent study from Israel underlining the potential cancer-fighting properties of this popular fruit, writes Lindsey Partos.
Scientists at Hebrew University of Jerusalem found that oroblanco and grapefruit juice upped the activity of hepatic detoxification enzymes in rats, thought to cut the risk of chemically induced carcinogenesis.
Investigating the impact of oroblanco (a pummelo-grapefruit hybrid) and grapefruit juice, Michal Hahn-Obwercyger and colleagues observed that both juices “significantly increased activity and expression of the hepatic phase I enzyme, cytochrome P450 CYP1A1”.
The human body has developed complex enzymatic mechanisms to detoxify xenobiotics, a chemical found in an organism but which is not normally produced or expected to be present in it.
The detoxification systems are highly complex and can vary greatly between individuals, linked to a person’s environment and genetic make-up, as well as lifestyle.
In addition to promoting the activity of the hepatic phase I enzyme, cytochrome P450 CYP1A1, scientists witnessed a marked trend toward enhanced NAD(P)H:quinone reductase (QR) activity through grapefruit juice consumption.
“These results suggest that these citrus fruits are bifunctional inducers, modulating both phase I and phase II drug-metabolising enzymes to enhance hepatic detoxification,” report the scientists in a recent issue of the Journal of Agricultural and Food Chemistry, 53 (5), 1828 -1832, 2005. 10.1021/jf048547a S0021-8561(04)08547-4.
These latest findings that hint at the potential chemoprotective function of these two fruits builds on existing research into the health value – notably cancer-fighting properties - of grapefruits, and citrus fruits in general.
Researchers at Texas A&M University reported last year that freeze-dried grapefruit pulp, similar to whole grapefruit, reduced the incidence of early colon cancer lesions in an animal model of the disease.
Meanwhile a researcher at Kanazawa Medical University in Japan showed that nobiletin, a compound found in tangerines, has also demonstrated possible action against colon cancer.
In another trial, presented at the symposium on health benefits of citrus fruits, taking place during the American Chemical Society’s national meeting in 2004, a team from the University of Hawaii reported that drinking grapefruit juice may help reduce the risk of cancer in smokers.
In a controlled study involving 49 smokers, the researchers found that those drinking three 6-ounce glasses of grapefruit juice a day reduced the activity of the liver enzyme CYP1A2 that is thought to activate cancer-causing chemicals found in tobacco smoke.
Roughly two-thirds of the world's grapefruit and grapefruit juice hail from Florida. Hurricanes that swept through the US last year caused great devastation to many crops; and causing a huge spike in grapefruit prices. Singlefold grapefruit oil that had retailed for around $10-$11 a kilo for the past five years, soared to $75-$80 a kilo.
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Chef2Chef News Desk