Mar. 23 -- MONDAY, March 19 (HealthDay News) -- Despite aggressive public campaigns urging a more healthful diet, Americans still aren't eating the recommended daily servings of fruit and vegetables, two new studies found.
Since the 1990s, the Dietary Guidelines for Americans have stressed eating at least two servings of fruits and three servings of vegetables every day. But, Americans are still falling far short of that goal, according to the reports.
"We used National Health and Nutrition Examination Surveys dietary data to determine the trends of fruit and vegetable consumption between 1988 and 2002," said Sarah Stark Casagrande, a graduate student at Johns Hopkins Bloomberg School of Public Health, and lead author of the first report.
"We found that there was no trend for increased fruit and vegetable consumption over time," she said. "Only 11 percent of U.S. adults meet the guidelines for both fruits and vegetables."
In the study, the researchers collected data on 14,997 adults from 1988 to 1994, and 8,910 adults from 1999 to 2002.
Casagrande's team also found that 62 percent of the study participants didn't eat any fruit daily, and 25 percent didn't eat vegetables daily. Overall, there was no improvement in Americans' fruit consumption, and there was a small decrease in vegetable intake during the study period.
That means just 28 percent of Americans meet the guidelines for fruits, and 32 percent meet them for vegetables.
Not eating enough fruits and vegetables is a serious public health concern, Casagrande said, because a diet rich in fruits and vegetables is associated with a lower risk of obesity and certain chronic diseases, such as cardiovascular disease, diabetes and some cancers.
The study is published in the April issue of the American Journal of Preventive Medicine.
The findings mirror a report released last week by the U.S. Centers for Disease Control and Prevention that found only 32.6 percent of adults eat fruit at least two times a day, and only 27.2 percent eat vegetables at least three times a day. That falls well below the national goal of getting 75 percent of Americans to eat fruit two or more times a day and 50 percent to eat vegetables three or more times a day by 2010.
In the second study in the American Journal of Preventive Medicine, Ashima K. Kant, a professor in the Department of Family, Nutrition and Exercise Sciences at Queens College in New York City, and colleagues also used National Health and Nutrition Examination Surveys to see if the diets of non-Hispanic blacks have improved relative to the diets of whites.
Their finding: Little progress has been made in closing the divide between blacks and whites.
"In 1971-74, blacks had lower intakes of vegetables, potassium, and calcium, and these differences have persisted in the latest survey in 1999-2002," Kant said. "The race differentials were not explained by race differentials in income and education," she added.
"There is a need to identify reasons for the persistence of race differences and explore culturally appropriate means to increase the intake of at-risk nutrients and food groups among blacks," Kant said.
One expert thinks more public education is needed to help people understand the link between diet and disease.
"We have ongoing research that shows that people are not eating adequate amounts of fruits and vegetables in their daily diet," said Linda Nebeling, acting associate director of the Behavioral Research Program in the Division of Cancer Control and Population Sciences at the U.S. National Cancer Institute.
The issue is not awareness of the guidelines, Nebeling said. "It is issues of accessibility and the environment and other barriers to eating well," she said.
Nebeling, the author of an accompanying editorial in the journal, said the National Institutes of Health is working with the CDC and with private groups to create a new program to reach people with the message about the importance of diet.
"We are looking at doing more about diet, physical activity and well-being," she said. "We have to help people in the search for health and well-being to overcome the barriers to eating a healthful diet."
In line with that, the CDC and the Produce for Better Health Foundation introduced on Monday a new public health initiative called "Fruits and Veggies -- More Matters," designed to encourage healthy eating.
Meanwhile, a related study in a separate journal found that canned and frozen, as well as fresh, fruits and vegetables all can contribute to a healthful diet.
Canning fruits and vegetables locks in nutrients, according to the study by researchers at the University of California, Davis, and reported in the Journal of the Science of Food and Agriculture. For some nutrients, canned products are higher than fresh ones and have a longer shelf-life.
Frozen fruits and vegetables may be more nutritious in some cases if stored for short periods of time under controlled temperatures. Moreover, fresh fruits and vegetables are best if eaten within three days after purchasing, according to the report, which was funded by the Canned Food Alliance.
For more information on a healthful diet, visit the U.S. Department of Health and Human Services.
SOURCES: Sarah Stark Casagrande, graduate student, Johns Hopkins Bloomberg School of Public Health, Baltimore; Ashima K. Kant, Ph.D., professor, Department of Family, Nutrition and Exercise Sciences, Queens College, New York City; Linda Nebeling, Ph.D., M.P.H., R.D., acting associate director, Behavioral Research Program, Division of Cancer Control and Population Sciences, U.S. National Cancer Institute, Bethesda, Md.; March 2007, American Journal of Preventive Medicine; Journal of the Science of Food and Agriculture; March 19, 2007, CDC press release