Ellagic acids falls into the category of a phytochemical, or a chemical produced by plants that may transmit certain health benefits but that are not essential elements such as vitamins or minerals. Flavenoids, carotenoids, phytoestrogens and lignans are all classified as phytochemicals. Ellagic acids show promise of slowing tumor growth in laboratory animals and in cells grown in the lab, but they have not been proven to have the same benefit in human bodies. While most types of nuts contain ellagic acid, certain ones have more than others.
Nut Types and Amounts
Nuts highest in ellagic acid are walnuts and pecans. Researchers from the National Cancer Institute tested the amount of ellagic acid in various food types. Their results, reported in the December 1989 issue of the "Journal of Food Composition and Analysis" found that walnuts contained 590 micrograms of ellagic acid, compared to 330 mcg in pecans. Both contained less ellagic acid than raspberries and blackberries, which had 1,500 mcg of ellagic acid.
Ellagic Acid Possible Benefits
Proponents of ellagic acid claim it acts as an antioxidant and can prevent growth of cancer cells. It may also reduce the effects of estrogen on stimulating cancer cell growth in breast cancer. Other claims include the potential to help the liver remove cancer-causing agents from the blood, and antibacterial and antiviral properties.
Study Results
Studies in humans have not proven that ellagic acid has benefits in treating cancer, although laboratory studies have shown that ellagic acid may slow the growth of new blood vessels that feed tumors; and it may also prevent cell growth in a number of different cancers, including liver, lung, esophagus, skin and colorectal cancers. A human study in men with prostate cancer conducted by Italian researchers, published in the April 2005 issue of "European Urology," found that ellagic acid lessened chemotherapy side effects such as low white blood cell count but did not change the course of the disease or improve survival rates. Another study, reported in the July 2006 issue of "Clinical Cancer Research," found that pomegranate juice, which contains high levels of ellagic acid, slowed the increase of prostate-specific antigen, a marker for cancer growth in men with prostate cancer.
Considerations
Ellagic acids may have benefits in treating certain types of cancer, although this has not been proven in humans. But nuts have a number of other benefits beyond ellagic acid that make them a worthwhile snack. The United States Food and Drug Administration allows almonds, peanuts, pecans, pistachios and walnut manufacturers to include a statement that says evidence suggests but doesn't prove that 1.5 oz of nuts per day may reduce the risk of heart disease, while the American Heart Association suggests substituting nuts for meat as part of a heart-healthy diet.
References
- American Cancer Society; Ellagic Acid; November 2008
- Memorial Sloan-Kettering Cancer Center; Ellagic Acid; March 2011
- "Journal of Food Composition and Analysis"; Extraction, stability, and quantitation of Ellagic Acid in Various Fruits and Nuts; Elaine Daniel, et al.; December 1989
- "European Urology"; Support Ellagic AcidTherapy in Patients with Hormone Refractory Prostate Cancer (HRPC) on Standard Chemotherapy Using Vinorelbine and Estramustine Phosphate ; Mario Falsaperla, et al.; April 2005
- Linus Pauling Institute: Phytochemicals
- "Clinical Cancer Research"; Phase II Study of Pomegranate Juice for Men with Rising Prostate-Specific Antigen following Surgery or Radiation for Prostate Cancer; Allan Pantuck, et al.; July 2006
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