'Orange' You Glad You Checked The Expiration Date? Study Says For Most Vitamin C, Drink Your Orange Juice Soon After Purchase

4/1/2002

From: Tom Ryan, Bridget McManamon or Lori Ferme, 800-877-1600, ext. 4894, 4769 or 4802 (media only), all of the American Dietetic Association

CHICAGO, April 1 -- The vitamin C content of increasingly popular ready-to-drink brands of orange juice can drop from 45 milligrams per cup to zero within four weeks after opening, according to a study published in the April issue of the Journal of the American Dietetic Association.

The study, led by registered dietitian and professor of nutrition at ASU, Carol Johnston, also found frozen reconstituted orange juice contains more vitamin C than ready-to-drink juice, although the exact amounts depend on when the juice is consumed following purchase.

Johnston and her co-author Dusti Bowling, a former undergraduate student of Johnston, recommend that ready-to-drink orange juice should be purchased three to four weeks prior to the expiration date and consumed within one week of opening.

"We don't want people to stop drinking orange juice for any reason at all," Johnston said. "We just want them to know that the frozen concentrate orange juice contains more vitamin C and may be a better nutritional choice. People don't eat broccoli, spinach or red peppers daily, and the thing that's great about orange juice is Americans consume it regularly."

"Orange juice is one of the best sources of vitamin C, folic acid and soluble fiber," said Los Angeles-based registered Dietitian and ADA Spokesperson Gail Frank. "When you buy orange juice, drink it as soon as possible. This will allow you to get the most bang for your buck."

The researchers analyzed two brands of frozen juice and two brands of ready-to-drink juice and found orange juice from concentrate contains 86 milligrams of vitamin C per fluid cup when first prepared, dropping to 39 to 46 milligrams after four weeks of storage. The study did not offer a recommendation whether consumers should choose frozen or ready-to-drink juice.

Ready-to-drink juices, on the other hand, start with "significantly lower" amounts of vitamin C than frozen, according to the study -- 27 to 65 milligrams per cup when the container is opened, and zero to 25 milligrams four weeks later.

Oxygen in the air is responsible for most vitamin C loss in packaged orange juice, meaning routine handling during the production process as well as storage in non-airtight containers after opening can reduce the amounts of vitamin C both before and after purchase.

"While the average person needs only about six milligrams per day of vitamin C to avoid health problems like scurvy, low intake of vitamin C can lead to fatigue, feelings of listlessness and may lead to more serious complications," Johnston said.

Johnston said previous studies have shown vitamin C deficiencies among U.S. adults have risen from five percent to 16 percent in the past 20 years, and the amount of vitamin C consumed by Americans has dropped 20 percent since the mid-1970s.

During roughly the same period, Johnston noted, "increasing sales of pasteurized, ready-to-drink orange juice resulted in a marked shift in the industry" -- the number of factories producing concentrates decreased and the number producing ready-to-drink juice increased.

According to the study, the vitamin C content of orange juice is "highly variable and dependent on, for example, the variety and maturity of the oranges, fresh fruit handling, processing factors and packaging. Pasteurized, ready to serve orange juice typically contains 25 percent less vitamin C per serving than frozen concentrates, a result in part of heat destroying the vitamin C."

The Journal of the American Dietetic Association is the official research publication of the American Dietetic Association and is the premier peer-reviewed journal in the field of dietetics and nutrition. With nearly 70,000 members, the American Dietetic Association is the world's largest organization of food and nutrition professionals. Based in Chicago, ADA serves the public by promoting optimal nutrition, health and well-being. Visit ADA at www.eatright.org.