Tuesday, September 11, 2007

Avocados Help Prevent Oral Cancer, New Study Shows

Excerpts from a 9/10/07 article in The Produce News by Rand Green

Nearly three years ago, a study conducted at the University of California at Los Angeles found that "nutrients in avocados can work together to inhibit the growth of prostate cancer cells."

UCLA researchers "discovered that avocados are the richest source of lutein among commonly eaten fruits," according to a UCLA press release. Lutein is a carotenoid that acts as an antioxidant and that has been linked to reduced risk of prostate cancer in previous studies, but the UCLA study suggested that the combination of lutein and other nutrients in avocados "might have additive or synergistic effects against prostate cancer compared with pure lutein alone."

Now a new group of studies conducted at Ohio State University has shown that extracts from avocados inhibit the growth of pre-cancerous cells that lead to oral cancer, preventing them from developing into actual cancers.

The studies "suggest that individual and combinations of phytochemicals from the avocado fruit may offer an advantageous dietary strategy in cancer prevention," according to Haiming Ding of OSU's College of Medicine, who collaborated in the study along with Steven M. D'Ambrosio and A. Doublas Kinghorn of the OSU Comprehensive Cancer Center and Young-Won Chin of the OSU College of Pharmacy.

Mr. D'Ambrosio said, "We think these phytochemicals either stop the growth of precancerous cells in the body or they kill the precancerous cells without affecting normal cells. Our study focuses on oral cancer, but the finding might have implications for other types of cancer."

"In most cases, dietary phytochemicals act as antioxidants to prevent the initial events in cancer," the report states. "Avocado...contains numerous antioxidant phytochemicals." Various effects of extracts of these phytochemicals, both individually and in combination, on in-vitro precancerous cells were observed. "Taken together, this data suggest that phytochemicals isolated form the avocado" induce apoptosis of the cells, a "tightly regulated form of cell death."

The article concludes that "in-vitro and in-vivo studies are indicating that avocados should be added to the list of fruits as a part of a cancer-prevention diet. Avocados are a rich source of nutrients as well as cancer-preventing phytochemicals. While some of the individual phytyochemicals found in avocados have been well characterized, many new uncharacterized phytochemicals are being discovered with potential cancer-preventing activity.

"Studies described here and elsewhere are indicating that a combination of phytochemicals as would be found in the whole fruit and extracts from the fruit may be more efficient."

Julie Upton, an independent registered dietitian in San Francisco who is a consultant to the California Avocado Commission said, "what is interesting is this isn't the first study like this to find a link between avocados and anti-cancer properties. It is a relatively new science and we haven't even identified all of the phytonutrients in the fruit."

"Some studies have found little or no anti-cancer benefits realized from some individual anti-oxidants," Ms. Upton noted. "But in combination, as they are found in their natural state in fruits and vegetables, them seem to act synergistically" to produce "a much bigger benefit. I think that is really the key for the anti-cancer properties."