THURSDAY, July 17 (HealthDay News) -- For babies ready to graduate from breast milk or formula to cow's milk, the longstanding recommendation has been that they receive whole milk, instead of reduced-fat or fat-free milk.

But new guidelines from the American Academy of Pediatrics (AAP) now advise parents of toddlers who are overweight or obese, or those who have a family history of obesity, high cholesterol or cardiovascular disease, to switch to reduced-fat milk between 1 and 2 years of age. The new guidelines -- from the clinical report Lipid Screening and Cardiovascular Health in Childhood in the July issue of Pediatrics -- are part of a long list of new recommendations aimed at keeping children's cholesterol levels down to protect their long-term heart health.

"If you read the guidelines, the AAP has definitely changed their idea on this," said nutritionist Ann Condon-Meyers, of the Children's Hospital of Pittsburgh. "They're saying if you're between 12 months and 12 years, and you have certain risk factors, the use of reduced-fat milk would be appropriate."

That's a departure from previous thinking that held that whole milk, and the fat it contained, was essential to the proper development of a baby's brain, especially since milk is such a major component of the toddler diet.

Condon-Meyers said past recommendations weren't based on evidence from studies, but developed more from experience and common sense. Breast milk is high in cholesterol, she explained, and babies fed breast milk have good cholesterol levels -- not high, but not low either. One likely reason that nature provides a reasonable amount of fat in breast milk is that fat is vital to the development of the myelin sheath in the brain, said Condon-Meyers. "That's why we worry about children not receiving enough whole fat," she said.

Whole milk contains between 3.5 percent and 3.8 percent fat, while reduced-fat milk contains 2 percent fat, according to Condon-Meyers, who added that the term reduced-fat is synonymous with 2 percent.

The reason reduced-fat milk should be fine for kids who are overweight or obese, or have family risk factors such as high cholesterol, is that they'll still be getting some fat in the milk, and they may already have sufficient levels of fat in their bodies.

Condon-Meyers said she would want to carefully evaluate the diet of a child who's a vegetarian because cow's milk may be his or her best source of saturated fat, and children need a small amount of saturated fat to develop properly.

"Our research on children and cholesterol is definitely in its childhood phase. It's really a work in progress," she added.

After age 2, parents should start giving toddlers whatever milk the rest of the family drinks, and at that time, even skim (fat-free) milk is fine, Condon-Meyers said.

"Provided it's not the mainstay of a child's diet, children can make the transition to low-fat or skim milk, regardless of other risk factors," she said.

More information

Here's more from the American Academy of Pediatrics on healthy eating.