Do Low-Carb Diets During Pregnancy Lead to Fatter Kids?

By Valerie Ross | April 22, 2011 2:11 pm

What’s the News: Researchers have known for decades that what a woman eats during her pregnancy can impact her child’s weight later in life. Now, a new study shows a possible mechanism for how mom’s diet affects baby’s weight: Epigenetic changes—changes that can increase or decrease the expression of a particular gene but don’t alter the genetic sequence—to a gene involved in fat metabolism can be passed from mother to child during pregnancy.

How the Heck:

  • The researchers asked nearly 80 pregnant women in Britain about their diets during pregnancy (and checked their blood for traces of some foods, to provide a more objective measure of diet).
  • At the birth of each child, the researchers took a sample of the child’s DNA from the umbilical cord. They analyzed the DNA for methylation, a common epigenetic change that occurs when a structure called a methyl group latches onto a particular point in a person’s DNA. When the children were nine years old, the researchers measured their body fat.
  • Children with methylation of a gene called RXRα, which is important in helping fat cells develop normally and in regulating their metabolism, were more likely to be obese than children who didn’t have methylation on that gene, the researchers found.
  • The researchers then repeated the study with another group of women, this time measuring the children’s body fat at age six. Again, RXRα methylation predicted how much body fat the children had. Children’s body fat percentage increased from 17% to 21% as the proportion of methylated RXRα genes increased from 40% to 80%.
  • Looking back at what the mothers ate, the researchers found that a link between a low-carbohydrate diet early in pregnancy and higher levels of RXRα methylation.
  • Methylation of the RXRα gene predicted a quarter of the variation in children’s body fat levels—a better predictor of obesity than birth weight. This link persisted whether or not the mothers themselves were thin.

What’s the Context:

  • Researchers first observed the effects of a pregnant woman’s diet on the weight of offspring in the 1970s, studying the children of women who endured the Dutch Famine of 1944 while pregnant. These children were more likely to be obese, and to show other symptoms of metabolic syndrome, than children whose mothers had enough to eat during their pregnancies.
  • Other factors can influence epigenetic changes, too, such as environment after birth, diet, stress level, and smoking.

Not So Fast:

  • Since methylation of the RXRα gene only predicted a quarter of body fat variation, that leaves room for lots of other factors to play a role. Unsurprisingly, mom’s diet early in pregnancy isn’t the only—or even the primary—cause of obesity.

Reference: Keith M. Godfrey et al. “Epigenetic Gene Promoter Methylation at Birth Is Associated With Child’s Later Adiposity.” Diabetes online ahead of print, April 6, 2011. DOI: 10.2337/db10-0979

Image: Wikimedia / Melimama

CATEGORIZED UNDER: Health & Medicine
  • speedwell

    wow, my mother was conceived in post war germany, to poor parents who scrounged together all their resources and came to Canada when she was 5. I alway assumed her weight problem was 100% poor self control. And I had to scoff at the gene-theory because I had fat grandparents on all sides, but I worked at my weight and was able to keep from getting fat. We keep learning more and more than it’s not the genes as the environement of the genes during and after gestation. It seems that human evolution has already worked out these details that if food is scarse then genes turn on in a new way to ensure the new individual can thrive. And most of us have gone from rags to riches in the past hundred years, DNA wise.

  • TomToys

    I find this interesting. It does make some sense that at some level a mothers eating habits while pregnant could have some effect on what weight factors her child has a predisposition too.

  • Dana

    I find it interesting that they specifically compared low-carb eating to everything else. Oh, so the traditional Inuit had fat kids? No, they didn’t. Can we please look at the effects of a diet of mostly industrial foods now, because that’s what many Western women eat, particularly in the UK and USA, with America being worse.

    And, a four percent change in body fat? 17% is already kind of high, although maybe not for a grade school-aged child. If one’s body fat were at 10% and went up to 14% would we see all the hand-wringing?

    There is a difference between starvation and low carbohydrates. Your fasting glucose is enough to sustain the cells and tissues that really need it (there aren’t many). Your body can thrive on fatty acids otherwise, and even ketones. Those people in WWII *starved*, had very little food at all.

    And we don’t even know how the researchers defined “low-carb diet.” I’d be curious to know macronutrient ratios. It seems like every other time someone does research about “low-carb diets” it winds up being 30 percent carb or something like that. It seems they believe that anything under the 300g USDA recommendation is “low.” Who knows why.

  • Dana

    Also, birth weight may not be as important in obesity as previously thought, but it is still a risk factor for diabetes, plus it is a hazard to the mother during childbirth. Low-carb being the most effective way to control blood sugar even in a gestational diabetic, telling pregnant women not to eat that way so their kids won’t get 4% fatter later is a disgrace.

  • Susan

    I don’t think that Dana understands body fat. 17% is not high. A person with 10% body fat would be deathly sick. I find this study very interesting. I have struggled with my weight all my life. My sister is naturally thin. I have two sons. One is heavy. I had him at a time when I was fairly thin. The other is thin. I had him at a heavy point in my life. Any connection? I wonder.

  • Jenny

    “Looking back at what the mothers ate, the researchers found that a link between a low-carbohydrate diet early in pregnancy and higher levels of RXRα methylation”.

    Dana, it doesn’t seem like they targeted carbs. This is what they found.

  • Matt Harper

    I too have struggled with my weight all my life and I wonder if this could have been a factor!
    My Mother was a model and hence
    naturally thin and concerned with her image.
    I’d be very interested in any further research on this subject!


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