Health Mailbox

Q: I saw your article about trans fats. Recently, however, I read something that confused me. Does peanut butter contain trans fat? Does it make a difference if it's made with fully hydrogenated oils rather than partially hydrogenated?

A: To answer this question, I checked in with experts at the Tufts University Friedman School of Nutrition as well as the Peanut Institute. Trans fats are a particularly heart-unhealthy fat created during hydrogenation, a process that uses hydrogen to make fat more solid. Partially hydrogenated oils are soft, like margarine. The more completely you hydrogenate oil, the more solid it gets and the less trans fat it contains.

But because fully hydrogenated oil is solid and waxy, it cannot be used in most foods. The terms partially hydrogenated and hydrogenated tend to be used interchangeably, so if a food's label says it contains partially hydrogenated oils or hydrogenated oils, it contains some level of trans fat.

HEALTH JOURNAL Tale of Two Studies: Cutting Through Confusion on Virtual Colonoscopies You can e-mail Tara Parker-Pope at healthjournal@wsj.com.

Hydrogenated oils are added to peanut butter to keep its natural oils from separating. But the added hydrogenated oils make up only 1% to 2% of the ingredients. Furthermore, the added oils are nearly completely hydrogenated and therefore less trans-fat content. A 2001 U.S. Department of Agriculture study of 11 peanut-butter brands found that the amount of trans fat added was so small it was undetectable, accounting for less than 0.01% of the sample. The Peanut Institute says that under FDA labeling requirements, regular peanut-butter brands can claim zero trans fats because the amount is less than 0.5 gram per serving.

Consumers can buy natural peanut butter, which contains no trans fat whatsoever. But if you still prefer the regular kind, don't worry. The amount of trans fat you're getting is negligible. Says Alice Lichtenstein, director of Tufts cardiovascular nutrition laboratory: "Better someone to have standard peanut butter than a bologna sandwich high in saturated fat."

* * *

Q: Thank you for clarifying the hazards of television viewing for toddlers. My wife and I diligently avoid watching television when our two-year-old son and eight-month-old daughter are awake. We do listen to a lot of music, and it frequently plays in the background when our children are playing. Should we turn off the stereo as well?

A: I took your question to Dan Anderson, the University of Massachusetts-Amherst professor who has led research on television and child development. While Dr. Anderson has shown that TV in the background can be disruptive to children's play, it's not known whether music has the same effect. "There is some research that indicates that homes that have a lot of sound -- from any source -- have kids who don't develop as well as kids from quieter homes," Dr. Anderson says.

But before you turn your house into a total quiet zone, remember a key concern is whether television or music is interfering with your interaction with your child. Are you listening more to the music than to your child? Or does the music inspire you to pick up your toddler and dance with him or her? Most experts believe the biggest negative of media isn't the media itself, but the fact that it can interrupt normal parent-child interactions.

Another reader asked whether leaving the television on but turning off the sound -- the way many people watch sporting events -- would have any impact on kids. Dr. Anderson has proposed a study of that very issue. So while we don't know the answer yet, stay tuned.

***

Q: Have you seen any data on the effect of the "Baby Einstein" videos on very young children

A: We know the so-called Mozart effect -- the idea that children become smarter by listening to classical musical, has been debunked. As for the popular Baby Mozart and Baby Einstein videos, "there's no evidence that babies learn anything from them at all," Dr. Anderson says.

But there's no evidence that the videos are bad for baby either. Again, the only real concern is whether time spent watching baby videos interferes with physical play or time spent with a parent. Experts point out that the videos are slow-paced, so there's little worry about overstimulation. In addition, babies have short attention spans and are unlikely to watch for very long. The reality is that a baby video is harmless, and can buy parents a few minutes to run to change the wash or just enjoy "down time" with their child.