Less than a quarter of Americans eats the five daily servings of fruits and vegetables that the National Cancer Institute recommends, but online programs may help boost those numbers, a new study hints.

As part of the Making Effective Nutrition Choices study, some 2500 people logged on to a website providing information on the benefits of eating more fruits and vegetables and ways to incorporate these healthy foods into their diets.

Three months into the study about 70 percent of subjects were eating five or more servings of fruits and vegetables on an average day, up from 20 percent at the starting point. That increase held for the rest of the year-long study.

It was surprising to see such a large jump in the number of participants reaching the guidelines so early on, said study leader Dr. Christine Cole Johnson, and also to have those results hold for the next nine months. In most nutritional studies, you're happy if you get a half-serving increase, Johnson said. But this study showed average increases of at least two servings daily.

Because the study included men and women aged 21 to 65 from around the country, the results indicate that a well-designed website could be used to educate more widely on the importance of fruit and vegetable consumption, Johnson said. We think this could reach a large number of people and change habits on a national level, she said.

The results of the study are published in the latest issue of the American Journal of Public Health.

In the study, conducted at five U.S. sites, the researchers assessed change in fruit and vegetable intake associated with visiting a website that provided tailored nutritional information, with or without motivational emails, and an untailored control website.

The two websites had the same basic design, but the tailored website provided personalized nutritional information based on responses to a survey given at the outset, while the control site provided general information about nutrition related to fruits and vegetables. With the tailored website, the messages they were given were based on concerns they had (about increasing consumption) and how to address those, Johnson said.

When the study began, the participants averaged 4.4 fruit and vegetable servings daily according to a 16-item food frequency questionnaire and 3.3 according to a 2-item questionnaire about average daily fruit and vegetable consumption.

By the end of the study, both questionnaires showed that daily fruit and vegetable consumption had increased by more than two servings, on average. Participants who accessed the tailored website showed comparable increases, whether or not they received email counseling, of about 2.7 servings daily, while those who used the generic website increased their daily servings by about 2.35.

The study participants reported an overall high level of satisfaction with the websites and the information they received on them, Johnson said. Statistically, it's hard to say what effect the motivational emails had on the results, she said, but study participants reported that they liked that feature and found it helpful.

Non-minority women over 50 with high levels of education were the most likely to stick with the program and increase their servings, the study found.

It was somewhat surprising, Johnson noted, that the web-based program was less popular with younger participants. Study co-author Dr. Gwen Alexander is currently working on a program aimed at younger participants. It needs to be in front of them, accessible and easy, Alexander said.

SOURCE: American Journal of Public Health, January 2010.

Medicine