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  .

WEDNESDAY, July 16 (HealthDay News) -- Empathy comes naturally to children, a new report shows.

Using functional MRI scans on normal kids aged 7 to 12, researchers found the parts of the children's brains that were activated when shown pictures of people in pain, according to findings published in the current issue of Neuropsychologia.

Study author Jean Decety, a professor in the departments of Psychology and Psychiatry at the University of Chicago, reported that empathy appears to be "hard-wired" into the brains of normal children, as opposed to being solely the result of parental guidance or nurturing.

"Consistent with previous functional MRI studies of pain empathy with adults, the perception of other people in pain in children was associated with increased hemodymamic activity in the neural circuits involved in the processing of firsthand experience of pain...," Decety wrote.

Knowing how the brain responds to pain may help scientists understand the relationship between brain impairments and anti-social behavior, such as bullying, he said in a University of Chicago news release.

Follow-up interviews with the participants showed they perceived wrongdoing in the animations where someone was hurt. "Although our study did not tap into explicit moral judgment, perceiving an individual intentionally harming another person is likely to elicit the awareness of moral wrongdoing in the observer," Decety wrote.

More information

The National Institute on Aging has more about how the brain works.

TUESDAY, July 15 (HealthDay News) -- By the time children reach their teens, their level of physical activity drops significantly, new research shows.

Kids who were averaging three hours of moderate to vigorous activity when they were 9 barely manage to get more than a half-hour of daily exercise by the time they reach 15, according to a study in the July 16 issue of the Journal of the American Medical Association.

"Kids' activity is decreasing dramatically between 9 and 15," said study author Dr. Philip Nader, professor emeritus of pediatrics at the University of California at San Diego in La Jolla.

Nader said the reasons for the drop are many.

"There may be competing, more interesting things to do; physical education is being done away with in some places, and so is recess; there aren't as many open spaces or parks, and being outside is one of the main things that keeps people active," he said.

Plus, children don't get the same routine daily activity that youngsters from a generation or two ago did. "Kids used to just run around and ride their bikes everywhere, and kids used to walk to school. Now, parents drive them," Nader noted.

The lack of physical activity is linked to the growing problem of childhood obesity, and most experts recommend that children should be getting at least one hour of moderate to vigorous activity each day, reports the study.

To assess how close children were coming to that goal, Nader and his colleagues followed a group of 1,032 kids beginning in 2000, when the children were 9, until 2006, when they were 15.

Half of the group was male, and almost one-quarter came from low-income families.

At 9, the children engaged in an average of three hours of moderate to vigorous physical activity each day. From that point on, daily exercise dropped an average of 38 minutes per year on weekdays and 41 minutes per year for weekend activity. At 15, teens participated in daily moderate to vigorous activity for an average of 35 minutes on the weekend and 49 minutes on weekdays.

Boys stayed more active than girls, averaging an extra 18 minutes on weekdays and 13 more minutes on the weekends. Girls dropped to less than one hour of activity daily on weekdays at about 13.1 years old, while boys didn't reach that mark until 14.7 years.

"This drop-off has always been there. Very young kids are extremely active, and as kids get older, they get into different lifestyles and different activities," said Dr. Goutham Rao, clinical director of the Weight Management and Wellness Center at Children's Hospital of Pittsburgh.

"Games like hide-and-go-seek get displaced by homework and computer time," he noted.

What's really missing today, he added, is the everyday activity. "Kids don't walk to school anymore, and that's probably the most physical activity they might get. No one uses stairs or rides bikes anymore. And, our environment isn't always suitable for those things," said Rao.

"Parents need to recognize that activity is an important part of kids' routine, just like schoolwork," said Rao.

Nader added that exercise should really be a family affair, and that parents need to model good exercise behavior.

More information

For tips on getting your kids up off the couch, visit the Nemours Foundation KidsHealth  .

TUESDAY, July 8 (HealthDay News) -- A new sweet treat that actually prevents children's cavities should please children and their parents, researchers say.

The tasty syrup, which contains the sugar substitute xylitol, prevented early decay in infants' teeth and may play a role in protecting permanent teeth, says a team from the United States and the Marshall Islands, in the South Pacific.

Xylitol has long been approved by the U.S. Food and Drug Administration and is already found in food products such as chewing gum.

The compound protects children's teeth by reducing the number of oral bacteria that cause decay, explained study author Dr. Peter Milgrom, a professor of dental public health sciences at the University of Washington, Seattle.

"I kind of look at tooth decay as a kind of malnutrition," he added. A diet high in sugar promotes the bacteria that take in sugars, metabolize them, and produce the lactic acid that creates tooth decay, the researcher said.

The study involved 102 children from the Marshall Islands, ranging from 6 to 15 months of age. The researchers picked these islands as the study site, because childhood tooth decay occurs there at rates that are nearly triple that seen among kids on the mainland.

According to the researchers, 76 percent of the children whose caretaker applied the xylitol-laden syrup to their teeth three times a day were free of cavities a year later.

That compares to 48 percent of the children who did not receive daily xylitol applications.

Milgrom was expected to present the results this week at the annual meeting of the International Association for Dental Research in Toronto.

"It's a real problem that we've got all this dental disease in kids, and we really don't have all the tools we need to battle it," he said. "Of course, we knew that xylitol had these benefits for teeth from other studies that have been done, but they had never been done in small children. So, we sort of put two and two together," he added.

The bacteria, which are the "bad actors" here, can't metabolize sugars from xylitol, and so they die off, Milgrom explained. Only the so-called "good" bacteria that do not create decay and can tolerate being around xylitol live, he said.

Preventing early tooth decay is important to children's overall health in a number of ways, Milgrom added. He said that children with early decay tend to be underweight, often fail to thrive, and don't eat or sleep well, which affects their performance in preschool.

Early tooth decay also is a problem among many children in the United States, according to Dr. Paul Casamassimo, a professor of pediatric dentistry at Ohio State University and a spokesman for the American Academy of Pediatric Dentistry.

For example, in Ohio, about half of five-year-olds have some tooth decay, he said. That number tends to be higher in minority communities because of poor diets and lack of access to dentistry.

Decay in baby teeth is a "gateway disease that leads to decay in permanent teeth," Casamassimo added. "It's probably related to the fact these people have these bacterial factors in their mouths that continue on."

The study, which was co-authored by researchers from the Marshall Islands Ministry of Health, was funded by the U.S. National Institute of Dental and Craniofacial Research and the HRSA Maternal and Child Health Bureau. Milgrom said none of the researchers have any financial ties to manufacturers of xylitol.

There's more on keeping kids' teeth healthy at the American Academy of Pediatric Dentistry  .