Nutrients in Oranges Help Protect Against Several Cancers for Up to 24 Hours After Eating
April 04, 2005
SHERMAN OAKS, CA (APRIL 4, 2005) – Juicy, delicious oranges are an excellent source of vitamin C and fiber, but the fruit also offers a healthful nutritional bonus in the form of limonoids, which may help fight cancers of the mouth, skin, lung, breast, stomach and colon, according to research with animal and human cellsup>1.
Scientists at the USDA Agricultural Research Service have demonstrated that each time we bite into a citrus slice our bodies readily access a type of limonoid called limonin. A study recently published in the Journal of Agricultural and Food Chemistry showed that limonin remains in the bloodstream for up to 24 hours after consumptionup>2. By comparison, the healthy phenols in green tea last 4 to 6 hours. Scientists theorize that this significant length of absorption may help explain the limonin’s ability to fight cancer cells, which may proliferate if they are not continuously suppressed.
Sixteen healthy men and women participated in the USDA research study. The volunteers consumed a dose of pure limonin glucoside, which is the parent compound present in citrus in about the same amount as vitamin C. Once consumed, the body converts limonin glucoside into limonin. The participants gave blood samples before they consumed the limonin glucoside and 3, 6, 12 and 24 hours afterwards. To avoid skewing the results, they didn’t eat or drink any citrus products for 3 days before and 3 days after taking part in the study. For most volunteers, the concentration was highest within 6 hours after they consumed the limonin glucoside and five volunteers still had some limonin after 24 hours.
Oranges and grapefruit* are excellent sources of fiber and vitamin C. They also offer potassium, folate and disease-fighting antioxidants. Citrus fruits are included in dietary programs from the world’s leading nutrition organizations including USDA’s Dietary Guidelines for Americans, Produce for Better Health (PBH) Foundation’s 5 A Day Program, American Heart Association, American Cancer Society and the National Cancer Institute.
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As one of the world's oldest and largest citrus marketing cooperatives, Sunkist Growers is owned by more than 6,000 citrus growers in California and Arizona. For more citrus information and healthy recipes, visit www.sunkist.com.
up>1 Report to Horticulture Australia Ltd, Project No. CT01037. Consumer Science Program, Commonwealth Scientific and Industrial Research Organization (CSIRO) Health Sciences & Nutrition. June 2003
up>2 Manners GD, Jacob, RA, Breksa III, AP, et al, “Bioavailability of Citrus Limonoids in Humans,” Journal of Agricultural and Food Chemistry, Vol. 51, No. 14, 2003.
*Some prescription drugs may interact with many foods including grapefruit. Anyone with questions about how their medication might interact with their diet should talk to their doctor or pharmacist for more information. For the majority of Americans, there is no reason to stop enjoying the delicious, healthy benefits of grapefruit.
Editor’s Note: Scientific abstract available