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Additional recommended knowledge
Ellagic acid is a primary constituent of several tannin bearing plants which produce the category of tannins known as Gallotannins. These, when hydrolised by water give rise to ellagic acid and gallic acid.
Many such plants include Terminalia chebula, Terminalia belerica, two related species which are ingredients of the celebrated Ayurvedic health promoting medicine known as Triphala.
Triphala has three ingredients the third being Emblica officinalis These tannin bearing galls and fruits have more ellagic acid content than the other celebrated sources such as raspberries etc. The "wellness" claim for thriphala may well be based on this fact.
Ellagic Acid and cancer
Research in cell cultures and lab animals has found that ellagic acid may slow the growth of some tumors caused by certain carcinogens. While this is promising, at this time there is no reliable evidence from human studies showing that ellagic acid in any form can prevent or treat cancer. Further research is needed to determine what benefits it may have, although Professor Gary Stoner from Ohio State University, referring specially to dark (black and blue) raspberries (in combination with anthocyanins) registered a patent on June 23, 2005 relating to fighting cancers and their metastases with ellagic acid.
There are also reports that ellagic acid may help the liver to break down or remove some cancer-causing substances from the blood.
Some supporters have claimed these results mean that ellagic acid can prevent or treat cancer in humans. This has not been proven. Unfortunately, many substances showing promise against cancer in lab and animal studies have not been found to be useful in people.
Ellagic acid has also been said to reduce heart disease, birth defects, liver problems, and to promote wound healing. One 2004 study published in the journal Clinical Nutrition (see reference below) showed clearing of plaque from the carotid artery after three years of supplementation with pomegranate juice, which contains ellagic acid. There are few results from human studies regarding other claims at this time.
The highest levels of ellagic acid are found in raspberries, strawberries, and pomegranates.
Extracts from red raspberry leaves or seeds, pomegranates, or other sources are said to contain high levels of ellagic acid, and are available as dietary supplements in capsule, powder, or liquid forms. The best dose of these preparations is not known. Because they are sold as dietary supplements (as opposed to drugs) and are derived from foods, they are generally recognized as safe (GRAS) by the Food and Drug Administration. Companies that sell them are not required to prove effectiveness or additional safety, as long as they don't claim they can prevent, treat, or cure a specific disease.
In recent years, researchers have begun focusing on phytochemicals, which are compounds produced by plants. There is a huge amount of folklore that surrounds phytochemicals, but scientific investigation into their effects is still in the early stages.
Ellagic acid was studied in the 1960s mainly for its effects on blood clotting. Early published research on ellagic acid and cancer first appeared in the 1970s and 1980s. With the publication of several small lab studies in the mid 1990s, ellagic acid began to be promoted on the Internet and elsewhere as a means of preventing and treating cancer.
Almost all studies conducted on ellagic acid to date have been done in cell cultures or lab animals.
Several studies in lab animals have found that ellagic acid can inhibit the growth of skin, esophagus, lung, and other tumors caused by carcinogens. Other studies have also found positive effects. A recent study in cell cultures found that ellagic acid may act against substances that allow tumors to form new blood vessels. Further studies are needed to determine if these results apply to humans.
In the only study reported thus far in humans, Italian researchers found that ellagic acid seemed to reduce the side effects of chemotherapy in men with advanced prostate cancer, although it did not help slow disease progression or improve survival. The researchers cautioned that more research would be needed to confirm these results.
The interaction between certain phytochemicals like ellagic acid and the other compounds in foods is not well understood, but it is unlikely that any single compound offers the best protection against cancer. A balanced diet that includes five or more servings a day of fruits and vegetables along with foods from a variety of other plant sources such as nuts, seeds, whole grain cereals, and beans is likely to be more effective in reducing cancer risk than eating one particular food, such as raspberries, in large amounts.
Problems and complications
Eating berries or other natural sources of ellagic acid is generally considered safe, but should be part of a balanced diet including several sources of fruits and vegetables each day.
Ellagic acid is available in supplement form, but it has not been tested for safety. Some reports indicate it may affect certain enzymes in the liver, which could alter levels of some drugs in the body. For this reason, people taking medicines or other dietary supplements should speak with their doctor before taking ellagic acid.
Relying on this type of treatment alone, and avoiding conventional medical care, may have serious health consequences.
The Hollings Cancer Institute at the University of South Carolina has conducted a double blind study on a group of 500 cervical cancer patients that gained a lot of attention. Nine years of study have shown that a natural product called ellagic acid is causing G-arrest within 48 hours (inhibiting and stopping mitosis - cancer cell division), and apoptosis (normal cell death) within 72 hours, for breast, pancreas, esophageal, skin, colon and prostate cancer cells.
Clinical tests on cultured human cells also show that ellagic acid prevents the destruction of the p53 gene by cancer cells. Additional studies suggest that one of the mechanisms by which ellagic acid inhibits mutagenesis and carcinogenesis is by forming adducts with DNA, thus masking binding sites to be occupied by the mutagen or carcinogen. Ellagic acid can be found in different foods.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Ellagic_acid". A list of authors is available in Wikipedia.|