Leafy Green Vegetables Prevents Cancer
The Scientific Evidence that Supports the Health Claim
Jul 23, 2009
Chlorophyll - the ubiqutous green coloring in plant - is of considerable interest to researchers because of its potential anticarcinogenic activity and because of its relative abundance in the human diet (green fruits, vegetables, etc.) Chlorophyll and chlorophyllin, the food-grade derivative of chlorophyll, have been used historically in the treatment of several human conditions without evidence of toxicity. Chlorophyll: Bactericide, Vulnerary, Deodorant
Both substances have been shown to exert profound antimutagenic behavior towards a wide range of potential human carcinogens. Chlorophyll and clorophyllin form tight complexes (substances) with some known cancer forming chemicals such as polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines ((HAAs). This "binding" of carcinogens may interfere with gastrointestinal absorption of potential carcinogens, thereby reducing the amount that reaches susceptible tissues.
Not all cancers start out malignant. Some are initiated by chemicals (procarcinogens like those in the cytochrome P450 family) that must first be metabolized to activate carcinogens that are capable of damaging DNA or other critical molecules in vulnerable tissues. Since these initiators are needed to activate some carcinogens, inhibition of cytochrome P450 enzyme may reduce the risk of some chemically induced cancers. Carcinogenesis 1995 by Yun CH et al.
Test tube studies suggests that chlorophyllin reduces the activity of cytochrome P450. A recent study published by Chimploy and colleagues showed that chlorophyll stops the cell cycle of human colon cancer cells. This is due to the inhibition of ribonucleotide reductase acivity (an enzyme that plays a key role in DNA synthesis and repair). Their study was published in the 2009 issue of the International Journal of Cancer.
Researchers also found that chlorophyll and chlorophyllin are effective against aflatoxin-B1 (AFB1) - a liver carcinogen produced by certain species of fungus found in moldy grains and legumes such as corn, peanuts, and soybeans. In hot humid parts of Africa and Asia where there are improper grain storage facilities, high levels of dietary AFB1 are linked with higher risks of liver cancer. Also, the combination of hepatitis B infection and high dietary AFB1 exposure increases the risk of liver cancer even more.
In the liver, AFB1 is metabolized to a carcinogen capable of binding DNA and causing mutation - a change in a gene that may or may not result in an altered gene product. In experimental animals, chlorophyllin treatment signifcantly reduced the DNA damage caused by AFB1- induced liver cancer.
Because liver cancer in humans caused by dietary AFB1 exposure takes time, an intervention trial became necessary in order to determine if chlorophyllin administration will reduce the risk of liver cancer in humans.
A randomized-placebo controlled trial was conducted in China among a population with a high risk of liver cancer and chronic hepatitis B infection. In this study, participants took either a placebo or 100 mg of chlorophyllin 3 times daily. After 16 weeks of treatment, urinary levels of AFB1-guanine (an indicator of high-risk liver cancer) was found 55% lower among those who took the chlorophyllin pills than those who took the placebo, suggesting that chlorophyllin supplementation before meals can markedly reduce AFB1-induced DNA damage.
Researchers are hopeful that chlorophyllin supplementation will offer some protection to a high-risk population with unavoidable dietary AFB1 exposure. The research was published in the 2003 issue of Mutation Research.
References
Waladkhani AR & Clemens MR " Dietary Phytochemicals on Cancer Development" in: Vegetables, Fruits, and Herbs in Health Promotion. Watson RR(ed) CRC Press September 2000, page 5
Tachino N et al. " Mechanisms of the in vitro antimutagenic action of chlorophyllin against benzo-a-pyrene; studies of enzyme inhibition, molecular complex formation, and degradation of the ultimate carcinogen" Mutation Research 1994; 308(2):191-203
Egner PA et al. "Chlorophyllin intervention lowers aflatoxin-DNA adducts in individuals at high risk for liver cancer" Proceedings of the National Academy of Sciences USA, 2001;98(25):14601-14606
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