Leafy greens and beans aren't the only foods that pack a punch of folate, the vitamin essential for a healthy start to pregnancy.

Researchers now have used genetic engineering--manipulating an organism's genes--to make tomatoes with a full day's worth of the nutrient in a single serving. The scientists published their results in this week's online edition of the journal PNAS, Proceedings of the National Academy of Sciences.

"This could potentially be beneficial worldwide," said Andrew Hanson, a plant biochemist at the University of Florida at Gainesville who developed the tomato along with colleague Jesse Gregory. "Now that we've shown it works in tomatoes, we can work on applying it to cereals and crops for less developed countries where folate deficiencies are a very serious problem."

Folate is one of the most vital nutrients for the human body's growth and development, which is why folate-rich diets are typically suggested for women planning a pregnancy or who are pregnant. Without it, cell division would not be possible because the nutrient plays an essential role in both the production of nucleotides--the building blocks of DNA--and many other essential metabolic processes.

Deficiencies of the nutrient have been linked to birth defects, slow growth rates and other developmental problems in children, as well as numerous health issues in adults, such as anemia.

"Folate deficiency is a major nutritional deficiency, especially in the developing world," said Parag Chitnis, program director in the National Science Foundation's Division of Molecular and Cellular Biosciences, which funded the research. "This research provides the proof-of-concept for the natural addition of folate to diet through enhancement of the folate content of fruits and vegetables."

The vitamin is commonly found in leafy green vegetables like spinach, but few people eat enough produce to get the suggested amount of folate. So, in 1998, the Food and Drug Administration made it mandatory that many grain productssuch as rice, flour and cornmeal be enriched with a synthetic form of folate known as folic acid.

Folate deficiencies remain a problem in many underdeveloped countries, however, where adding folic acid is impractical or simply too expensive.

"There are even folate deficiency issues in Europe, where addition of folic acid to foods has not been very widely practiced," Gregory said. "Theoretically, you could bypass this whole problem by ensuring that the folate is already present in the food."

Will doctors be recommending a healthy dose of salsa for would-be pregnant women anytime soon? Probably not, the researchers say.

"It can take years to get a genetically-engineered food plant approved by the FDA," Hanson said. "But before that is even a question, there are many more studies to be done--including a better look at how the overall product is affected by this alteration."

And there is another hurdle the researchers must clear. Boosting the production of folate in tomatoes involved increasing the level of another chemical in the plant, pteridine. Little is known about this chemical, which is found in virtually all fruits and vegetables.

Written from a news release by National Science Foundation.