The 11 Nutrients Your Pregnancy Depends On: A Guide to Prenatal Nutrition

Cover for a guide to the key nutrients needed during pregnancy

Part two of three. Protein, iron, iodine, folate, B6, vitamin D, calcium, magnesium, zinc, omega-3s, and vitamin E: what each one does for you and your baby, and where to find it.

Last time, we talked about how many women start pregnancy already running low, and why the months before conception matter so much. Today we're going nutrient by nutrient.

I want to be upfront: this is a long list, and you do not need to memorize it. Think of it as a reference you can come back to. For each nutrient, I'll cover what it does, how much you need, how often women fall short, and the foods that deliver it best.

The amounts below are the official recommendations for pregnant women ages 19 to 50, from the National Institutes of Health. The shortfall numbers come from a large study of more than 1,000 pregnant women in the United States, most of whom were already taking a supplement.

How Much Protein Do You Need in Pregnancy?

Everything your baby builds, from muscle to organs to the placenta itself, is made from protein. Your own body is building too: more blood, a growing uterus, and more breast tissue.

The official recommendation is 1.1 grams of protein per kilogram of body weight per day. But a study that measured protein needs directly in pregnant women found they were higher than that: about 1.2 g/kg in early pregnancy and about 1.5 g/kg later on. For a 150-pound woman, that works out to roughly 80 grams a day early in pregnancy and closer to 100 grams in the third trimester.

That's a lot more than many women eat, especially when nausea makes a plain bagel the only thing that sounds remotely okay. My favorite strategy is protein at every meal and snack, starting with breakfast: eggs, Greek yogurt, cottage cheese, fish, poultry, meat, tofu, tempeh, lentils, and beans.

Iron in Pregnancy

During pregnancy, your blood volume expands by roughly half, and every new red blood cell needs iron. Your baby is also building its own iron stores to last through the first months of life.

How much: 27 mg a day, up from 18 mg before pregnancy.

How often women fall short: about 36%.

Low iron in pregnancy can leave you exhausted, breathless, and foggy, and it's linked to a higher risk of preterm birth and low birth weight. It's also one of the most common reasons women feel terrible in the second and third trimesters and assume it's just pregnancy.

Best sources: red meat, oysters, mussels, dark poultry meat, lentils, beans, tofu, and spinach. Pair plant sources with vitamin C (citrus, peppers, tomatoes, berries) to boost absorption, and keep coffee and tea away from iron-rich meals.

One caution: more than a quarter of pregnant women in that study were getting more iron than the safe upper limit, almost entirely from supplements. This is exactly why I want ferritin tested rather than guessed.

Iodine in Pregnancy

Iodine is how your thyroid makes thyroid hormone, and your baby depends on your thyroid hormone for brain development, especially before its own thyroid comes online partway through pregnancy.

How much: 220 mcg a day. The American Thyroid Association recommends a supplement of 150 mcg daily, ideally starting three months before conception.

Best sources: fish and seafood, seaweed (in moderation), dairy, eggs, and iodized salt. Many women have switched to sea salt or specialty salts, which usually aren't iodized, and in one check of 59 best-selling prenatal vitamins, only 34 contained any iodine. That combination is how a quiet gap develops, and national data suggest many pregnant women in the U.S. are iodine insufficient.

Folate and Folic Acid in Pregnancy

Folate helps build DNA and new cells, and it's essential for closing the neural tube, which becomes your baby's brain and spinal cord, within the first 28 days after conception.

How much: 600 mcg a day in pregnancy. Anyone who could become pregnant is advised to take 400 mcg of folic acid daily.

How often women fall short: about 16%, while about a third were getting more folic acid than the upper limit.

You may have heard that some women should avoid folic acid because of a gene variant called MTHFR and take methylfolate instead. This is a genuinely debated topic. The CDC's position is that people with common MTHFR variants can process folic acid, and that folic acid is the form proven in research to prevent neural tube defects. Many integrative practitioners prefer methylfolate for some women. I'll walk through how I think about it in part three, when we talk about choosing a prenatal.

Best sources: dark leafy greens, lentils, chickpeas, beans, asparagus, avocado, and citrus.

Vitamin B6 for Pregnancy Nausea

B6 helps your body use protein and build neurotransmitters, and it may be the most welcome nutrient of the first trimester. The American College of Obstetricians and Gynecologists considers vitamin B6, alone or combined with doxylamine, a first-line treatment for pregnancy nausea. (Please talk with your provider about dosing rather than improvising.)

Interestingly, the same guidance notes that taking a prenatal vitamin for a month before conception may reduce how severe nausea is later. One more reason to start early.

How much: 1.9 mg a day for general needs.

Best sources: poultry, fish, potatoes, chickpeas, bananas, and pistachios.

Vitamin D in Pregnancy

Vitamin D helps you absorb calcium and supports your baby's bones, your immune system, and your mood. It behaves more like a hormone than a vitamin.

How much: 15 mcg (600 IU) a day is the official recommendation, though many practitioners, myself included, prefer to dose based on a blood test.

How often women fall short: about 46%, even with supplements.

The main source is sunlight on your skin, which is a tall order for those of us in the Pacific Northwest from October through roughly June. Food sources are limited: fatty fish, egg yolks, and fortified foods. This is one where testing and a supplement usually make sense.

Calcium in Pregnancy

Your baby's skeleton is built from calcium, mostly in the third trimester. If your intake runs low, your body draws on your own bones to make up the difference.

How much: 1,000 mg a day.

How often women fall short: about 13%.

Best sources: dairy, canned sardines and salmon with the bones, tofu made with calcium sulfate, fortified plant milks, kale, bok choy, and almonds.

Magnesium in Pregnancy

If there's one nutrient on this list I'd bet you're short on, it's this one. Nearly half of pregnant women in that study, about 48%, weren't getting enough.

Magnesium is involved in hundreds of reactions in the body. It helps muscles relax, supports sleep, and plays a role in blood sugar balance. The leg cramps so many women get in pregnancy are one reason I always ask about it.

How much: 350 to 360 mg a day.

Best sources: pumpkin seeds, almonds, cashews, spinach, black beans, avocado, whole grains, and dark chocolate. (Finally, a craving with a scientific alibi.)

Zinc in Pregnancy

Zinc is needed for cell growth and DNA production, which is to say, for building a whole new person. It also supports your immune system and your sense of taste and smell.

How much: 11 mg a day.

How often women fall short: about 11%.

Best sources: oysters (by far), beef, poultry, pumpkin seeds, cashews, chickpeas, and lentils. Zinc from plants is less well absorbed, so vegetarian and vegan women may need more attention here.

Omega-3s and DHA in Pregnancy

The omega-3 fat DHA is a building block of the brain and the retina, and your baby accumulates it rapidly in the third trimester. Expert groups generally recommend 200 to 400 mg of omega-3s a day in pregnancy, and most women don't get there without fish or a supplement.

There's also research suggesting that omega-3 supplementation can lower the risk of early preterm birth, with the clearest benefit in women whose omega-3 levels were low to begin with. A simple blood test called the omega-3 index can tell you where you stand.

Best sources: low-mercury fatty fish like salmon, sardines, anchovies, herring, and trout. The Dietary Guidelines for Americans recommend 8 to 12 ounces of low-mercury fish per week during pregnancy. Plant sources like flax, chia, and walnuts provide ALA, which the body converts to DHA only in small amounts.

Vitamin E in Pregnancy

Vitamin E is an antioxidant that protects cell membranes, which matters a great deal when cells are dividing as fast as they do in pregnancy.

How much: 15 mg a day.

How often women fall short: about 43%, which surprised me the first time I saw it.

Best sources: sunflower seeds, almonds, hazelnuts, peanut butter, avocado, olive oil, and spinach.

A Sample Day of Prenatal Eating

I know that was a lot. Here's what it can look like in a real day:

  • Breakfast: eggs scrambled with spinach, plus a slice of whole grain toast with avocado.

  • Snack: Greek yogurt with berries and a handful of pumpkin seeds.

  • Lunch: lentil soup with a side of greens and a squeeze of lemon.

  • Snack: apple slices with almond butter.

  • Dinner: salmon, roasted potatoes, and broccoli.

That single day covers a remarkable amount of ground: protein at every meal, iron with vitamin C, folate, magnesium, zinc, calcium, omega-3s, and vitamin E. Add a well-chosen prenatal for the gaps food can't reasonably fill (iodine, vitamin D, and often iron), and you're in good shape.

And on the days when all you can manage is crackers and ginger ale? That's okay. Pregnancy is long, and it's the overall pattern that counts.

Next time

In part three, we'll tackle the question I get asked constantly: how do you choose a prenatal vitamin that actually covers these gaps, without overdoing the ones you don't need?

If you'd like help building your own plan, learn more about my prenatal and postpartum nutrition support, or you can work with me here.

Chelsie Moore, MS, CNS, LDN, is a functional medicine clinician and integrative nutritionist at Moore Integrative Health in Portland, Oregon.

This post is for educational purposes only and isn't a substitute for individualized medical advice. Please talk with your provider before starting any supplement, especially during pregnancy.

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