Ellagic acid is a naturally occurring antioxidant found in blueberries and many other fruits and nuts. You may have heard ellagic acid mentioned in relation to its anti-cancer properties, which is partially why blueberries are often touted as being so healthy and beneficial. Animal studies seem to support the anti-cancer properties of ellagic acid, although the American Cancer Society cautions that there’s currently no reliable evidence that it can prevent or treat cancer in people. But in any case, there are many other nutrients in blueberries that make them an excellent addition to your diet.
Ellagic acid is classified as a polyphenolic compound, which is an especially strong type of antioxidant found in a variety of plant-based foods. Antioxidants are beneficial for your body because they eliminate or neutralize free radicals that have a tendency to damage tissues such as blood vessels and internal organs. Blueberries are not the richest source of ellagic acid, but they are a very good source. Red pigmented fruits, such as raspberries, strawberries, red grapes and pomegranates, often contain a little more ellagic acid than blueberries. Ellagic acid is also found in nuts such as walnuts and pecans.
Potential Anti-Cancer Properties
In animal studies, it’s been noted that ellagic acid not only acts as a strong antioxidant and mild antibacterial, but it also prohibits genetic mutations within cells, which seems to deter cancer cells from forming and spreading. Ellagic acid seems to be most effective for providing protective benefits against breast and prostate cancers because it reduces the effect of estrogen on the growth of estrogen-dependent cancer cells. Keep in mind, though, that these studies are usually done on rats and mice, so it doesn't necessarily mean ellagic acid will affect humans in the same way. In addition, the U.S. Food and Drug Administration does not currently recognize ellagic acid as an effective treatment for cancer or any other disease.
The ellagic acid content in blueberries and other fruit is dependent on many factors, such as soil content, growing conditions and ripeness. Organically grown blueberries have significantly higher concentrations of ellagic acid and other antioxidants compared to non-organically grown varieties. Therefore, if you want to maximize the health impact of berries, and perhaps other fruit, buy organic. Furthermore, freeze-dried blueberries may be even more concentrated in ellagic acid. Unlike some antioxidants and other nutrients, such as vitamin C, ellagic acid is a fairly hardy compound and is able to withstand various types of processing and storage conditions.
Other Nutrients in Blueberries
In addition to ellagic acid, blueberries contain many other antioxidants such as anthocyanins, which are primarily responsible for their dark blue color. Anthocyanins also act as mild antibacterials and anti-inflammatories. Blueberries are also good sources of vitamins C and K, manganese, soluble fiber and pectin. Clean conventionally grown blueberries carefully before you eat them, because they may be coated in pesticide residues.
- PDR for Nutritional Supplements; Sheldon Hendler and David Rorvik
- Natural Standard Herb & Supplement Reference: Evidence-based Clinical Reviews; Catherine E. Ulbricht and Ethan M. Basch
- Contemporary Nutrition: Functional Approach; Gordon M. Wardlaw et al.
- American Cancer Society Complete Guide to Complementary and Alternative Cancer Therapies; American Cancer Society
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.