A Michigan State University study presented recently at the American Institute for Cancer Research annual conference revealed that orange juice slashed the incidence of colon cancer in animals by 22 percent.
This report by Maurice Bennink, professor of food science and human nutrition at Michigan State and study co-author, is the first to document that drinking regular strength, not-from-concentrate orange juice significantly inhibits the development of colon cancer in animals.
Previous studies have shown that double strength orange juice or carotenoid-rich extracts from citrus inhibit the development of different types of cancers.
"This study confirms that some foods are going to help reduce the risk of some cancers," Bennink said. "While people are looking at supplements and pills to live longer, there is some synergy in a number of different chemicals present, as they are with whole foods. It's probably better to stay with whole foods, and orange juice is one of these."
Bennink and his MSU team - Y. Miyagi, A.S. Om, and K.M. Chee - fed rats a diet for 28 weeks that included orange juice that was not from concentrate -- identical to juice available in grocery stores -- and gave another group of rats distilled water to drink.
The scientists induced colon cancer in the rats and later examined them for tumor development. The rats that drank orange juice had 22 percent fewer incidence of early tumor development.
"The results from this study provide further evidence that certain substances in orange juice slow down the cancer process in the colon," Bennink said. "We have identified at least three classes of compounds in orange juice that may be responsible for reducing colon cancer."
Rates for digestive tract and hormone cancers vary widely among countries. Diet is considered one of the major factors accounting for such differences. Bennink and his associates knew that other research had shown that the compounds inhibited tumors in doses stronger than typically consumed by people.
Other research has shown that compounds found in orange juice and other citrus fruits -- called flavanones, limonoids and cumarins -- inhibited the development of some cancerous tumors. Bennink said it appears that the compounds change the characteristics of the lining of the colon, making it a less friendly place for cancer cells to develop.
The specific chemopreventive agents discussed in the report are hesperidin and limonin glucoside, which are phytochemicals that are found in citrus fruits and juices. Phytochemicals are chemical components of foods that do not belong to the traditional nutrient classes of fats, proteins, carbohydrates, vitamins or minerals.
Phytochemicals found in fruits, vegetables and legumes, such as flavonoids found in orange and grapefruit juices, have been receiving increasing attention for their anti-cancer roperties.
Cancer is the second leading cause of death in the U.S., exceeded only by heart disease. More than 1,500 people a day die from cancer, totaling approximately 563,100 Americans each year.
The study was funded by Tropicana Products Inc. and the MSU Agricultural Experiment Station.