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New Research Points to Risks of Excessive B12 During Pregnancy

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New Research Points to Risks of Excessive B12 in Pregnant Women


We’ve been told time and time again that vegans and in some cases, vegetarians, are at risk of consuming too little B12 because they don’t eat enough (or any) animal products. This comes with a list of symptoms including exhaustion, fatigue, memory loss, nerve sensations, and anxiety. But what you might not have heard of is on the other end of the spectrum. The real risk of pregnant women getting too much B12.

What is B12 Anyway?

B12, also known as cobalamin, is one of the eight essential B vitamins. Its main role is the proper functioning of the nervous system, brain health, and the production red blood cells. The body produces millions of red blood cells every minute, but when you have a deficiency of B12, your body doesn’t produce enough, which can result in anemia. Other symptoms include a sore tongue, menstruation problems, fatigue, weight loss, and pale skin.

A serious deficiency of B12 is really dangerous and can cause permanent symptoms like neurological changes, which can cause numbness in the hands and feet as well as difficulty holding your balance. It can also cause depression and brain damage that results in dementia. That’s why those at risk (and many of those that are not at risk of a deficiency) supplement to ensure that they’re getting enough.

Good Sources of B12

Getting B12 from your diet is always best because it's easily absorbable. Animal products are the best sources of B12. These include:

  • Lamb
  • Beef
  • Pork
  • Poultry
  • Fish (especially haddock, salmon, and tuna)
  • Milk
  • Cheese
  • Yogurt
  • Nutritional Yeast

Adults over the age of 14 years old should consume 2.4 micrograms (mcg) of vitamin B12 a day, pregnant women should have 2.6 mcg and lactating women should have 2.8 mcg. A three-ounce serving of beef contains most of the B12 you would need in a day. A serving of salmon also contains a day’s serving and an egg contains about 15 percent of your daily allowance.

How Too Much B12 Can Impact Pregnant Women

But like so many aspects of health, balance is important. Too much B12 is also not a good thing. Here’s the deal with B12: It’s a water soluble supplement, which means that when the body takes in too much B12, you usually excrete it in urine. And supplementing with B12 is sometimes a good thing if you’re a vegan or you’re over 50 and unable to properly extract enough from the foods you eat. The same, however, may not be true of pregnant women.

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From the Organic Authority Files

Research from the Johns Hopkins Bloomberg School of Public Health has shown that excessive amounts of B12 during pregnancy can increase the risk of autism. The study found that women with excessive levels of folate (B9) and B12 in their systems had a 17 times greater risk of autism. Researchers found that in women with folate levels significantly higher than necessary (four times the RDA), babies were twice as likely to be diagnosed with autism spectrum disorders. Very high levels of B12 in moms were also problematic, tripling the risk of having a child with autism.

Folate is a B vitamin found in many fruits and vegetables while the synthetic version, folic acid, is added to cereals and bread. Doctors aren't in any way saying to stop taking prenatal vitamins because they are essential to preventing birth defects in your baby's brain and spinal cord. But there is some concern about why some women had such extremely high levels in their blood. Doctors are also unsure of why the combination of high levels of B12 and folate caused such a problem. More research still needs to be done on the subject.

“Adequate supplementation is protective: That’s still the story with folic acid,” says one of the study’s senior authors, M. Daniele Fallin, PhD, director of the Bloomberg School’s Wendy Klag Center for Autism and Developmental Disabilities. “We have long known that a folate deficiency in pregnant mothers is detrimental to her child’s development. But what this tells us is that excessive amounts may also cause harm. We must aim for optimal levels of this important.” nutrient.”

In the non-pregnant, there’s no upper intake level where too much B12 becomes dangerous. But there is a level where it becomes useless and there have been cases of people taking over 20 mcg and it causing rosacea and acne.

What’s the Bottom Line with B12?

Much more research needs to be done on pregnancy and excessive B12, but this research does leave reason for concern. A simple blood test can help you figure out where you fall on the spectrum. Doctors contend that 200 to 900 picograms per milliliter (pg/ml) is within the normal range. If you fall below the normal range, amp up on organic, free range, grass-fed sources of animal protein like beef, eggs, salmon, and tuna. If you’re a vegan, enjoy tons of nutritional yeast (one of the only plant-friendly sources of the nutrient). But if you fall in this category you’ll likely need a moderate supplement.

If you have a gastrointestinal disorder like celiac disease and Crohn's disease, you may also have low levels. Certain medications as well as alcoholism (which depletes the body’s ability to absorb the nutrient) can also cause a deficiency. A single daily supplement (capsule or tablet) will generally have between 25 mcg and 1,000 mcg but while the doses are higher only a small amount gets absorbed. If you’re pregnant or thinking about getting pregnant, talk to your doctor before supplementing B12, especially beyond your prenatal vitamin.

Do you supplement B12? What are your favorite sources of B12? Are you scared of becoming deficient? We want to know! Drop us a line via Twitter @OrganicAuthority.

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