Vegetarian Diet During Pregnancy: Assessment and Support
Vegetarian diets include foods from plant sources and there are several variations of this diet. Lacto-ovo vegetarians consume milk and eggs. Vegans exclude any animal food sources and hence, may necessitate additional nutritional counseling. Approximately 10% of the population are vegetarians but only about 1% are vegans (Penney & Miller, 2008). Thus, it is no surprise that some providers may be misinformed about nutritional adequacy of a vegetarian, and in particular a vegan diet, during pregnancy. A woman on a vegan diet most likely has been criticized by well-meaning family and friends for her choice to stick with a strictly plant-based diet during her pregnancy. Dietary choices and beliefs may be an emotional touchstone for her. Nonjudgmental professional support is important for her overall well-being. According to the American Dietetic Association, well-planned vegetarian diets are appropriate during all stages of life, including pregnancy, lactation, infancy, childhood, and adolescence, and have many health benefits such as lower risk of obesity, heart disease, and diabetes (Rizzo et al., 2016). Evidence-based reviews show that vegetarian diets can be nutritionally adequate in pregnancy and result in positive maternal and infant health outcomes (Penney & Miller).
Differences of dietary practices among vegetarians make individual assessment of nutritional adequacy critical. A good place to start with the nutritional assessment is to ask how long she has been a vegetarian. If she has a long-term commitment to a plant-based diet, she is more likely to be knowledgeable of necessary nutrients. However, a dietary diary is still required to assess specific components of adequacy, which include protein intake, vitamin D, calcium, iron, zinc, and essential fatty acids, particularly N-3, and vitamin B12. Food sources rich in these nutrients in a well-planned vegetarian diet include: proteins (variety of amino acids such as grains, beans, and nuts), vitamin D (sunshine, fortified soy, cereals), calcium (broccoli, collards, kale, sesame seeds, almonds, soy), iron (soy, beans, lentils, kale, dried fruits), essential fatty acid N3 (flaxseed, canola oils), and B12 fortified foods (soymilk, tofu, cereal, nutritional yeast).
Vitamin B12, also called cobalamin (Cbl), is the nutrient that is virtually absent in plant sources (and is also indirectly affected by deficiencies of these other nutrients) and so, requires special attention. Vitamin B12 is a water-soluble vitamin found in substantial quantities only in animal sources, although small amounts can be found (listed here highest to lower values) in sauerkraut, chlorella microalgae, spirulina, nori seaweed, klamath microalgae, shiitake mushrooms, porcini mushrooms, and tea leaves (Rizzo et al., 2016). Vitamin B12 needs increase during pregnancy and lactation. The recommended dietary allowance of B12 has been determined at 2.6 mcg/day for pregnancy and 2.8 mcg/day during lactation, although these recommendations are based on limited evidence (Penney & Miller, 2008). While the vegan diet, which excludes all animal foods, is most likely to be deficient in B12, low levels of B12 have been found in Lacto-ovo vegetarians as well, perhaps because only about 50% of dietary sources are absorbed (Rizzo et al.). Research has shown the use of supplements or fortified foods appear to prevent deficiencies, indicating that a well-planned plant-based diet to be adequate and sustainable throughout pregnancy and lactation.