School vending machines and cafeterias will no longer sell soda or other sugary soft drinks under regulations approved by the Colorado Board of Education on Wednesday.

High school students will still be allowed to buy low-calorie sport drinks. But board members specifically barred diet soda.

"If they're allowed diet soda, kids get in the habit of drinking soda," said board member Evie Hudak.

The rules take effect on July 1, 2009, or when a school district completes its contract with a distributor.

The board vote was unanimous, following testimony by parents and medical experts who said only healthy choices should be available in schools.

"When all the bad choices are available at school, it undercuts parents' ability to guide their children through the fast-food and drink minefield," said Phyllis Albritton, an Evergreen parent who is active in the Jefferson County PTA.

The new rules could affect income that school districts have obtained by signing exclusive contracts with distributors.

For example, in the Jefferson County School District, the contract to carry Pepsi products is worth somewhere between $800,000 to $1 million, said Superintendent Cindy Stevenson. About $400,000 of that total goes directly into the district's general fund. The rest goes to individual schools to help underwrite student activities.

"We've already been moving in that direction," Stevenson said of the effort to curb sugar-laden soft drinks. "Pepsi also has been moving in that direction.

"It's been a way that we could fund things for kids, so it's just going to be a challenge," she said, referring to the funds generated by the contract.

She added that the new rules "are not a bad thing for the kids . . . There are trade-offs in life." She said the district would have to find a way to make it work.

The legislature last spring adopted a bill barring all but healthy beverages in schools. It directed the board to decide which drinks to allow. The bill aimed at reducing childhood obesity.

The board vote permits water, low-fat milk, low-fat flavored milk, milk substitutes approved by the U.S. Department of Agriculture and juice in elementary and middle schools.

High school students can buy the same items, but in larger portions, plus low-calorie sport drinks and other unspecified low-calorie beverages.

An amendment to bar diet soda passed unanimously.

Bruce Caughey of the Colorado Association of School Executives, the group that includes school superintendents, said he believes most districts are on their way to eliminating unhealthy beverages. He wasn't sure whether the districts were eliminating diet soda.

University of Colorado dental school professor Paul Bottone warned that many of the chemicals listed on diet sodas could prove harmful.

Pediatrician Sandy Stenmark said federal agencies have determined that artificial sweeteners in diet soda are not harmful. But she doesn't drink them or serve them to her children, she said.