Plant-Based Diet During Pregnancy

10-1 [Calcium]

Pregnant women do not need more calcium than before pregnancy.

The Dietary Reference Intake (DRI) for calcium remains unchanged during pregnancy, at 1,000 mg/day for women aged 19–50, because pregnant women tend to absorb more calcium (Ref. 3).

Just as before pregnancy, adequate calcium can be easily obtained through a plant-based diet. In fact, calcium absorption from plant foods is superior to that from dairy products (Ref. 11). Good sources of calcium include:

Calcium-set tofu, soybeans, dark leafy greens, bok choy, broccoli, beans, figs, sunflower seeds, tahini, almond butter, calcium-fortified plant milks, and calcium-fortified cereals and juices.

Eat these foods daily to meet your calcium needs.

10-2 [Essential Fats]

Alpha-linolenic acid (ALA) is an essential fat and an important component of the diet. The body converts ALA into long-chain polyunsaturated fatty acids (DHA and EPA), but conversion rates vary among individuals (Ref. 2).

The Adequate Intake (AI) for ALA is 1.1 g/day for women aged 19–50, increasing to 1.4 g/day during pregnancy (Ref. 1). ALA is found in many plant foods, especially flaxseeds and flaxseed oil. You can also obtain ALA from canola oil, walnut oil, walnuts, chia seeds, hemp seeds, kale, and soybeans.

However, the typical Western diet contains more omega-6 fats (from animal products and vegetable oils) than omega-3 fats. This excess can prevent omega-3 fats from being efficiently converted to EPA and DHA. Avoiding processed foods and baked goods such as chips can help you reduce unnecessary omega-6 fats.

Research shows that infants born to plant-based mothers have lower plasma and umbilical cord DHA levels (Ref. 7). Since plant-based eaters do not obtain DHA from their diet, their bodies must produce DHA from ALA. Because the rate at which people convert ALA to DHA and EPA varies, taking an algae-based DHA supplement (100–300 mg) may be good insurance. Consult your doctor to determine whether this supplement is right for you (Refs. 12, 13).

10-3 [Folate]

Folate is especially important in the early weeks of pregnancy and is crucial for helping prevent neural tube defects. Folate also has other functions. As the name suggests (derived from the word "foliage"), the natural source of folate is leafy green vegetables. Legumes are also rich in folate. Because diets vary from day to day, it is best to take a multivitamin or prenatal supplement providing at least 400 mcg of folate daily. Many breakfast cereals and other grain products are fortified with folate. An intake of 600 mcg of folate per day is necessary during pregnancy (Ref. 2).

10-4 [Iron]

Iron needs increase during pregnancy to support fetal and placental development and to sustain the increase in maternal blood volume (Ref. 14).

The DRI for iron is 18 mg/day for women aged 19–50, increasing to 27 mg/day during pregnancy (Refs. 3, 15). Iron requirements may be greater for plant-based eaters because iron from non-animal sources is less efficiently absorbed (Ref. 16). Because it can be difficult to meet growing iron needs through diet alone, doctors typically prescribe iron supplements (or iron-containing prenatal vitamins) regardless of the mother's dietary pattern. However, if your blood tests show normal iron levels, taking high-dose iron supplements may be harmful (Ref. 17). Consult your doctor to determine whether you need supplements.

Iron supplements should not be taken at the same time as tea, coffee, or calcium supplements, as these reduce iron absorption. Dairy products decrease iron absorption and should be avoided.

In addition to taking prescription vitamins or supplements, plant-based women should include iron-rich plant foods in their daily diet. Sources of iron include whole grains and fortified grains, legumes, nuts, seeds, dark green vegetables, dried fruits, and blackstrap molasses. Including vitamin C–rich foods in the diet (most fruits and vegetables) enhances the absorption of iron from plant foods.

10-5 [Protein]

Pre-pregnant women aged 19–50 are recommended to consume 0.36 grams of protein per pound of body weight. For a 125-pound woman, this is 125 × 0.36 = 45 grams of protein. During pregnancy, the daily protein requirement increases by 25 grams. Therefore, this woman would need 70 grams of protein per day during pregnancy. Protein sources in a plant-based diet include whole grains, legumes and lentils, vegetables, nuts, and seeds. As long as the plant-based diet is balanced, provides sufficient calories, and includes these foods, protein needs will very likely be met (Ref. 18).

10-6 [Vitamin B12]

Vitamin B12 intake needs only a slight increase during pregnancy, rising from 2.4 mcg/day to 2.6 mcg/day for women aged 19–50 (Ref. 2). Vitamin B12 can be obtained from fortified foods, such as fortified cereals, meat substitutes, plant milks, and nutritional yeast. Be sure to check labels to identify which foods are fortified.

Foods such as seaweed and tempeh are generally not reliable sources of vitamin B12. Since not everyone absorbs B12 effectively, take a prenatal vitamin or B12 supplement (at least 100 mcg of vitamin B12) (Ref. 19).

Taking an additional 250 mcg of chewable or sublingual vitamin B12 on an empty stomach can further raise B12 levels in the blood. Request that your B12 levels be checked in early pregnancy and during breastfeeding to ensure you are getting enough.

10-7 [Vitamin D]

Women of childbearing age and pregnant women need 600 IU of vitamin D per day. This is important for both the mother and the baby. Vitamin D is produced by the body after exposure to sunlight. For many people, 5 to 15 minutes of sun exposure on the arms, legs, hands, or face between 10 a.m. and 3 p.m. during spring, summer, and fall is sufficient to meet vitamin D needs. People with darker skin tones need longer sun exposure to achieve the same effect (Ref. 20).

Vitamin D is difficult to obtain through diet alone unless using fortified foods, although many ready-to-eat cereals and plant milks are fortified with vitamin D. Pregnant women who have limited sun exposure, live in northern latitudes, or have darker skin tones should ensure their diet includes vitamin D–fortified foods. Many prenatal vitamins also contain vitamin D.

10-8 [Zinc]

Zinc requirements increase during pregnancy. The DRI for women aged 19–50 is 8 mg/day, increasing to 11 mg/day during pregnancy (Ref. 3).

Plant-based pregnant women may have even greater zinc needs, as zinc absorption from plant-based diets is lower (Ref. 21).

Prenatal vitamins typically include zinc.

Zinc can also be found in legumes, nuts, whole grains, and cereals. Adding sprouted grains, legumes, seeds, and yeast-leavened breads to the diet can increase zinc absorption from plant sources. Soaking legumes before cooking and pairing zinc sources with acidic ingredients (such as lemon juice or tomato sauce) can achieve the same effect.

10-9 [Iodine]

Iodine is crucial for fetal brain development in early pregnancy. Getting enough iodine is especially important during the first months when the baby's brain is growing rapidly. Iodized salt (but not sea salt or Himalayan salt) and some fruits and vegetables contain iodine. However, the iodine content of fruits and vegetables varies depending on the soil in which they are grown.

Pregnant women, breastfeeding women, or women who are trying to conceive should supplement with 150 mcg of iodine daily in the form of potassium iodide (Ref. 22). Prenatal vitamins may not contain iodine, so if this is the case, be sure to take an additional iodine supplement.

10-10 [Choline]

Choline is essential for fetal brain development and may help prevent neural tube defects. The recommended daily intake for pregnant women is 450 mg (Ref. 1). Eat plenty of choline-rich foods such as tofu, soy milk, quinoa, legumes, peanut butter, cruciferous vegetables, and mushrooms. Consider supplementing with 250 mg of choline during pregnancy and breastfeeding, or as recommended by your obstetrician.

A note on dietary supplements: Your clinician may recommend supplements to ensure you meet your vitamin/mineral needs. Most prenatal vitamins will meet your requirements. If you wish to use any other dietary supplements, including herbal or botanical supplements, consult your clinician. Many herbal supplements have not been adequately tested for safety during pregnancy.