Nutrients during pregnancy: how much is too much?

You’ve heard about how important it is to get a wide variety of nutrients every day during pregnancy. But it’s possible to get too much of a nutrient, too. And there are a few vitamins that are dangerous when taken in very large amounts.

What kind of supplementation is okay in pregnancy?

When women become pregnant, there are certain vitamins that their bodies need more of. Some of these vitamins include folate (folic acid), calcium, and iron. Prenatal vitamins are helpful because they contain much of the daily amounts of these nutrients needed in pregnancy. If you take a prenatal multivitamin and eat a balanced diet during pregnancy, these will usually provide you with all the nutrients you need per day, without the need for further supplementation.

How can you avoid getting too much of a specific vitamin?

Once you get your provider’s approval, it’s important to know exactly how much of a vitamin you should be taking per day. You’ll also want to be aware of your intake of the vitamins over the course of a day. Knowing how much of a vitamin you should have every day can help you avoid going over the recommended limit.

What vitamins can be dangerous when taken in large amounts?

Because of the way they’re absorbed in the body, some vitamins can be dangerous in high doses, especially during pregnancy.

  • Vitamin A helps with vision, supports the immune system, and promotes the growth of tissue in the body. This vitamin comes in two different forms: beta-carotene and retinol. It’s possible to get toxic levels of retinol, but not of beta-carotene; this is important because retinol toxicity can result in birth defects. So it’s best to get most or all of your vitamin A from beta-carotene. The recommended amount during pregnancy is 750-770 RAE a day, and some beta-carotene sources include foods like leafy green vegetables, carrots, sweet potatoes, and cantaloupe. 
  • Vitamin B6, when taken in high doses, can cause low blood pressure, a higher risk of bleeding, and neuropathy, or a sense of numbness in the arms and legs. Women need about 1.9 mg of this vitamin every day in pregnancy, with a maximum intake of 100 mg. Anything over this level could be unsafe. You can get a healthy amount of B6 from foods such as pork, chicken, turkey, fish, bread, whole grain cereal, eggs, vegetables, and milk contain healthy amounts of this vitamin.
  • Vitamin C is an antioxidant that helps our body maintain its connective tissue, heal wounds, and absorb iron. When pregnant, you need about 85 mg of vitamin C per day. You don’t want to get too much of this helpful vitamin per day, though; the upper limit is around 2,000 mg, and too much can lead to stomach pain, cramps, heartburn, diarrhea, a headache, and more. To get a healthy daily intake, try eating an orange, a cup of strawberries, or a cup of broccoli, all of which have enough to help you meet your daily quota. Once you add your prenatal vitamin to the mix there’s generally no need for further vitamin C supplementation.
  • Vitamin D is produced by the body when you’re in sunlight, and you can also get it from wild salmon, fish oil, mushrooms, cheese, and egg yolks, among other foods. It’s hard to get too much vitamin D from the sun or food – your body regulates its levels – but there is such a thing as too much vitamin D in the form of supplements. It’s uncommon, but too much vitamin D can lead to too much calcium in the blood, which can cause nausea, a decrease in hunger, and kidney problems. Pregnant women should consume about 600 IU of vitamin D per day, and not more than 4,000 IU.
  • Niacin (vitamin B3) helps with things like high cholesterol, diabetes, and osteoarthritis. However, too much can cause blood sugar and liver problems, as well as hormone complications. Pregnant women should only consume 18 mg of niacin per day. Some foods that are high in niacin include meat, fish, milk, eggs, green vegetables, and beans.

Paying attention to how you’re supplementing your diet during pregnancy takes a little extra time, but it’s worth the work. For most women, a balanced diet and a daily prenatal multivitamin provide enough nutrients per day.

If your healthcare provider recommends and approves vitamin supplementation during pregnancy, make sure to keep an eye on your levels of each vitamin so as to avoid consuming an amount that’s higher than what’s recommended.

Learn more about prenatal vitamins


Sources
  • Alan R. Liss, LLC. “Recommendations For Vitamin A Use During Pregnancy.” Teratology. 35:269–275. Web. 1987.
  • “Vitamin B6 (pyridoxine).” Mayo Clinic. Mayo Foundation for Medical Education and Research. Nov 1 2013. Web.
  • “Fortify Your Knowledge About Vitamins.” FDA. U.S. Department of Health and Human Services, Mar 16 2016. Web.
  • Katherine Zeratsky, R.D., L.D. “What is vitamin D toxicity, and should I worry about it since I take supplements?” Mayo Clinic. Mayo Foundation for Medical Education and Research, Feb 5 2015. Web.
  • “Vitamin A.” HSPH. Harvard T.H. Chan School of Public Health, 2016. Web.
  • Anna Medaris Miller. “Everything You Need to Know About Prenatal Vitamins.” USNews. U.S. News and World Report, June 18 2015. Web.
  • Katherine Zeratsky, R.D., L.D. “Is it possible to take too much vitamin C?” Mayo Clinic. Mayo Clinic Foundation for Medical Education and Research, Feb 5 2015. Web.
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