Gut Check is a periodic look at health claims made by studies, newsmakers, or conventional wisdom. We ask: Should you believe this?

The claim

C

hildren of women who ate little or no meat while pregnant are more likely to abuse alcohol, tobacco, and marijuana at age 15 than are children of mothers who did eat meat.

Tell me more

Researchers analyzed data from 5,109 women and their children in a long-running study in England called ALSPAC (the Avon Longitudinal Study of Parents and Children), which has gathered years of data on what women did while pregnant and their children’s health. The less meat the women ate while pregnant, the more their children’s risk of drinking, smoking, or using marijuana as 15-year olds, Dr. Joseph Hibbeln of the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health and his colleagues reported on Wednesday in Alcoholism: Clinical and Experimental Research. (They were funded by the U.S. and U.K. governments and a charity, not meat producers.)

Roughly 10 percent of the 15-year-olds smoked at least weekly, drank enough to have behavioral problems, or used marijuana “moderately.” But teens of meatless moms were 75 percent more likely to have alcohol-related problems, 85 percent more likely to smoke, and 2.7 times as likely to use marijuana compared to teens of mothers who’d eaten meat while pregnant.

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The researchers suspected that any adverse effect of mom’s forgoing meat while pregnant involves vitamin B12, which is abundant in meat but not plants. They therefore dug deeper into their data, comparing two groups of women: those with a high-functioning form of the gene that brings B12 into both their cells and their fetus’s, and those without the high-functioning gene. In the latter, B12 doesn’t reach their cells or their fetus’s very well regardless of what they eat, so it shouldn’t matter if they got lots of B12 (in meat) or not.

Here’s what the researchers found: Among moms without high-functioning B12 genes, there was no difference in their teens’ risk of substance abuse whether they’d eaten meat while pregnant or not. The vegetarian mom/substance-abusing teen association held only among women with high-functioning B12 genes, in whom eating meat or not would affect how much B12 their cells and their fetus’s got. That seemed to strengthen the case for an association between a meatless, low-B12 pregnancy and children’s later substance abuse.

Really?

Of course, what mom eats while pregnant can affect the child’s health. B12 helps insulate neurons, including in the developing brain, which may be why too little seems to leave kids with impaired cognitive and social development. That might leave children with poorer impulse control and other deficits that can make them abuse drugs and alcohol. “I’m not surprised by the results,” said University of Oxford physiologist John Stein, who was not involved in the new study.

Other experts raised questions. While mostly well-regarded, ALSPAC has also produced head-scratching and possibly wrong findings, such as linking pregnant women’s acetaminophen use to their child’s behavior problems or moms’ eating fish and children being obese. With as much data as ALSPAC generates, statisticians worry that mining it all can produce spurious correlations, things that are linked only coincidentally and not in a meaningful way.

Another issue is that ALSPAC had pregnant women fill out questionnaires about their diet. It didn’t verify their reports or measure their B12 levels. That raises the possibility that women misremember what they ate while pregnant. “Self-reporting dietary intake and substance use/abuse can have errors,” said nutritionist Susan Levin of the Physicians Committee for Responsible Medicine, a nonprofit that advocates vegan diets. As a result, many nutrition studies based on self-report reach erroneous conclusions.

Because this is an observational study, the researchers can’t rule out the possibility that “women who choose to be vegetarian are different from those who do not,” Oxford’s Stein said. What kind of home a family lived in (publicly subsidized or owned), maternal education, and parents’ social class (white collar or manual laborer) was associated with at least as great an elevated risk of a child’s substance abuse as mom’s meatless pregnancy.

“No one would disagree that B12 is critical in the health of the fetus and beyond,” Levin said. “While B12 may well play a role [in teens’ substance abuse], many other factors could contribute to the findings, such as religion and personality traits of the parents and children, which were not measured or accounted for.” Hibbeln said he and his colleagues “are very sensitive to issues associated with confounding,” and is confident that a meatless pregnancy affects risk of substance abuse independently of other factors.

Is the parenting style of vegetarian moms different from that of meat-eating moms in a way that would affect kids’ likelihood of drinking or smoking? In fact, the researchers found that moms who avoided meat were (contrary, perhaps, to stereotype) not more permissive but more protective, keeping an eagle eye on their kids. That should decrease the kids’ risk of substance abuse, yet these were the mothers whose teens were more likely to smoke and drink.

“Many, many factors contribute to children’s substance use,” said Maureen Black of the University of Maryland School of Medicine, an expert on B12 and brain development. It’s a “long stretch to link it to maternal meat consumption during pregnancy.”

The verdict

The link between mom avoiding meat during pregnancy and her child’s later risk of substance abuse is an intriguing but unproved idea, and in any case the study authors say pregnant women don’t have to be carnivores to modify any such risk from going meatless, since B12 is also found in supplements.

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  • This is total crap. Must be funded by a meat producing companies. I’m from a family of vegetarians for generations and I can vouch no one in our family even drinks.
    Shit only this is.

    You listen to your heart and go by what’s right. Eat what you like . This is hilarious.

  • It’s too bad really. This is about mother’s. Mother’s huh? What’s it mean to be a mother huh? Vegans stop here. You already know. 208 that’s her name. One of 900 others in this place I like to refer to as concentration camp. A child, a kid, a baby calf of 3 years old is first raped by a long skinny metel rod filled with semen.(INSEMINATED) Injected with growth hormones Tada!!!!!! Now she’s a MOTHER too! But only for 5 minutes. Once the baby calf is ratcheted out of her hooha. The baby is then draged away NEVER to see her MOTHER again. I say HER because the boy calf is killed right there or sold for slaughter. There she’ll die at the age of five years old.
    (The average lifespan of a dairy cow) Locked up behind bars from birth till she bleeds out onto the concrete. As I weep and die inside. All day every day beatings, cused at, kicked in the face. Walks eats and sleeps in 2 inches of sh*t and p*ss. She’ll have 2 -3 babies before she’s shot in the back of the head because she slipped on the p*ss covered concrete and breaks her pelvis. Those babies are rapped and and shot in the back of the head as well. 3 years later gets sick from open wounds contaminated by sh*t and p*ss, That she got from getting hit with canes pipes and the blade of a skidsteer. One eye hanging on the outside of her face. She was beat with a cane in the face because she was too slow. her was shot to make body count 6 years later. To keep up their quota. Soooooooooo MOTHER what’s it gonna be HUH?

    • There are 4 studies so far in which vegetarians and vegans had doubled rates of depression and anxiety compared with meat-eaters, and a trial where a diet that included red meat improved depression.
      None of this is surprising, some of the reasons are discussed above.
      Recommending this diet at a population level, especially to young people, is dangerous, because it obviously requires special care.

  • If someone ended an article about vitamin C by saying there was no need to eat fruit as vit C is available from supplements, we’d know they were stark staring mad.
    This is yet another study that has failed to confirm, to put it mildly, that vegetarian diets are a healthy option with regard to mental health.

  • the vegetarian world in the east …buddhists,majority of Hindus, Janis must all be drug addicts and or drunks????

  • This is an outrageously stupid study and the conclusions are beyond ludicrous. I am 67 years old and have been a vegetarian since I was 20 years old. My son has NEVER eaten meat and was raised to be a vegetarian. He was in intellectually gifted classes for his entire school career and is currently attending medical school. He was fed mother’s milk until I weaned him and then almond milk after that. He has NEVER smoked or did drugs. That would be totally antithetical to the values of healthy living that he grew up with. He is now in his twenties. Women who are vegans and vegetarians are much more conscientious about the foods and substances that we teach our children to consume. It is a lifestyle and values choice to be a vegetarian pregnant mother who raises a vegetarian child to adulthood. No way would women like us ever tolerate our child getting involved with drugs, alcohol or tobacco.

  • As a parent of grown children, so with anecdotal observations all around of family and friends, being overly protective (helicopter parenting) seems to often drive adolescents to rebel. This seems like a plausible hypothesis to explain the findings discussed here.

  • this sounds like Funded by Meat industry..Either Writer is paid directly or indirectly paid by Meat industry or study itself is funded by Meat industry..SHAME! SHAME!SHAME!!!! write should disclose howmuch he/she or their media or anyone been benefited??

    • Arun, — yes — indirectly funded by the meat industry. Although tw implies the meat industry did not fund the study, we all know the influence of the meat industry on the agencies of the U.S. government. One only has to look at the back and forth shift of personnel from one to the other.

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