Even babies in the womb may hate green vegetables: Study

Researchers in England may have confirmed that babies don't like green vegetables even before they're born.

A new study offers a look at how unborn children respond to what their moms eat and how they react to different flavors in utero.

About 100 pregnant women in the U.K. were given capsules containing powdered versions of either carrots or kale. Thirty-five women consumed the equivalent of one medium carrot, 34 women ate the equivalent of 100 grams of chopped kale, and the remaining 30 were a control group who didn't eat either.

After 20 minutes, doctors used 3D ultrasounds to study the facial reactions of the babies as they began to taste what their moms ate. Babies whose mothers ate carrots mostly had happy expressions, while those who tasted kale frowned or grimaced.

"We are the first ones who could actually show on an ultrasound scan the facial expressions in relation to the food which the mother has just consumed," study co-author Dr. Nadja Reissland told NBC News. She is the head researcher at the Fetal and Neonatal Research Lab at Durham University.

The women in this study were 32 to 36 weeks along in their pregnancies.

Reissland said the ultrasound images suggest babies at that stage of development had similar reactions as adults who taste something bitter, but it's unknown whether they have emotional likes and dislikes as adults do.

The grimacing faces in the ultrasounds "might be just the muscle movements which are reacting to a bitter flavor," Reissland said.

But she noted that unborn babies are known to make faces.

"If you look at it from 24 to 36 weeks’ gestation, their expressions become more and more complex," Reissland said.

She told NBC News that powdered kale and carrots were selected over juices or raw vegetables to make sure each participant ate the same number of calories. Capsules were used because some expecting mothers hated the taste of kale and the researchers didn't want their negative reactions to influence their unborn children.

"I had a number of people in the lab, and I tried to give them a kale juice to drink, and you should have seen the expressions," Reissland said.

The capsules also helped preserve the flavor of the vegetables as they were digested.

"The bitter flavor gets into the small intestines and then into the mother’s blood and then into the placenta and the amniotic fluid," she added. "This process seems to take around 20 minutes, and what you then get is a specific reaction of the fetuses to that flavor."

The researchers hope that by understanding how babies respond to different flavors in the womb, they can suggest diets for mothers that will help their children tolerate different foods when they are young.

"If we can actually get [children] to like green vegetables and to perhaps not like sweets that much, it might help with regard to their weight gain and their weight balance," Reissland said.

The study was featured on the "Today" show, where the co-hosts gushed over the faces the babies made.