4 Things a Dietitian Wants You to Know About Pregnancy

As our Director of Scientific Affairs and a registered dietitian, Dr. Mastaneh Sharafi is our resident resource for all things pregnancy nutrition-related. And just to put a finer point on it: Did we mention she’s expecting her second child?

Like many second-time moms, Dr. Mastaneh is approaching this pregnancy with a renewed sense of wisdom—and of course, that science degree definitely comes in handy, too. Below, she reveals why the foods you eat during pregnancy can have even more of an impact than you might have bargained for. (Spoiler: Did you know that you can impact your baby’s flavor preferences while they’re still in the womb?)*

Make your snacks work for you.

That means picking nutritious foods that benefit you and support the growth of your baby. For example, Dr. Mastaneh has calculated that to support recommended weight gain during her own pregnancy, she should aim for an extra 400 to 600 calories per day during her third trimester. (That might be different for you, so it’s definitely worth having a conversation with your doctor to work on an eating strategy that’s right for your pregnancy.)

But she makes sure she gets more bang for her nutritional buck by meeting those calorie needs with nutrient-dense foods. “For example, one of my snacks is hard boiled eggs,” she says. “I really like it because it's a really good source of choline.” (Choline and folate help support your baby’s brain development.)*

As for her other snacks? “A quarter cup of hummus—I eat it with cucumber or with baby carrots sometimes. I also have one cup of plain yogurt and I add some fruit.”

During your pregnancy, you’re impacting three generations of DNA.

“Pregnancy is so fascinating for me because honestly, this is the only time in your life that three generations are exposed to the same environments,” says Dr. Mastaneh. “I'm the first generation, my fetus is the second generation and the third generation is the reproductive cells of the fetus.” That means that factors like the environment, and—you guessed it—your diet can have even more of an impact than you realize (1).*

This phenomenon can be filed under the study of epigenetics: To put an elementary spin on a pretty Advanced Biology topic, epigenetics basically describes a variety of factors that can impact gene expression: The DNA in every one of our cells is fixed, but only certain genes are turned “on,” depending on that cell’s behavior at any given time. Epigenetics is still pretty new in the realm of scientific research, but scientists do know this: Our environment can have a pretty significant impact on gene expression. It’s why identical twins, who share the same DNA, actually start to diverge from the time they’re in the womb through the rest of their lives. They’re exposed to different things that may have an impact on gene expression (2).*

“That’s why diet becomes really important during pregnancy,” says Dr. Mastaneh. “Whatever is happening to you right now isn’t just impacting you.”

And on that note, what you eat during your pregnancy can impact your baby’s food preferences later on.

Believe it or not, this is Dr. Mastaneh’s particular area of expertise: chemosensory perception, which is basically the science of taste and flavor.

“The fetus begins swallowing amniotic fluid at around 12 weeks,” she explains. “Their tastebuds mature by 13 to 15 weeks, and by 28 weeks they develop a powerful sense of smell. So your diet during pregnancy may be able to help shape your fetus' food preferences.”

She cites one study in particular, published in Pediatrics in 2006. One group of women were instructed to drink carrot juice during their pregnancies and lactation, a second group was told to drink water during their pregnancy and carrot juice during lactation, and the control group drank water the whole time. After the babies were born, they were fed both plain and carrot-flavored cereal—and the babies who had been exposed to the carrot juice preferred the carrot-flavored cereal to the plain, while the control group did not (4). “It tells us that the fetus can get familiar with that flavor and they can learn it,” she says.

Want another example? “I drank a lot of pomegranate juice during the third trimester of my first pregnancy,” she adds. “My son loves pomegranates. All the tart foods—cranberries, black cherries.”*

When you’re choosing a prenatal vitamin, opt for MTHF folate over folic acid.

A quick refresher course: Up to one-third of women have a genetic variation that makes it trickier to efficiently utilize folic acid, the synthetic form of folate. It’s why we include a form called 5-MTHF folate in our multivitamins—it’s an absorbable form of the B-vitamin. (And that’s especially key for pregnancy, since folate supports gene expression and the neural tube development of your baby.)*

“I have the variation for MTHFR, so for me, folic acid is not an ideal option,” says Mastaneh. And for what it’s worth: “I also love the citrus taste of our prenatal,” she says.

References:

1. Coussons-Read M. E. (2013). Effects of prenatal stress on pregnancy and human development: mechanisms and pathways. Obstetric medicine, 6(2), 52–57. doi:10.1177/1753495X12473751
2. Cavalli, G., & Heard, E. (2019). Advances in epigenetics link genetics to the environment and disease. Nature, 571(7766), 489–499. doi: 10.1038/s41586-019-1411-0
3. Powledge, T. M. (2011). Behavioral Epigenetics: How Nurture Shapes Nature. BioScience, 61(8), 588–592. doi: 10.1525/bio.2011.61.8.4
4. Mennella, J. A., Jagnow, C. P., & Beauchamp, G. K. (2001). Prenatal and postnatal flavor learning by human infants. Pediatrics, 107(6), E88. doi:10.1542/peds.107.6.e88