Plant-based diets have grown in popularity over the years. There are many reasons why people choose this way of eating - environmental, cultural, health, ethical, socioeconomic - and it is a choice that I respect. So I want to ensure you are educated, prepared and supported if you choose to eat a plant-based diet during your pregnancy.

As you are probably aware, your nutritional needs increase during pregnancy. Some of these nutrients are difficult to obtain in adequate amounts from plant foods. And hence, you will need to be a little more thoughtful of which foods you are eating to ensure your nutritional needs are met. Careful planning and supplementation is essential.

This blog will take a look at some of the nutrients that need some extra attention when following a plant-based diet. More information on plant-based diets in pregnancy can be found in my book, Nurture the Seed, alongside many delicious plant-based recipes. You can also book in for a one on one consultation for individual advise. I offer a one hour sessions which includes a full nutrition assessment and diet/supplement intervention. If you think you have the diet side covered and just want some help with supplements, I also offer a 30 minute supplement consult.

Vitamin B12

I want to start with vitamin B12 - a crucial nutrient during pregnancy that is essential for red blood cell formation, brain function and DNA synthesis. If you already follow a plant-based diet, you will know that vitamin B12 is only found in bioactive forms in animal foods. Therefore, supplementation (or fortification) is essential whether you are pregnant or not. My advice to you if you are hoping to conceive in the near future, would be to get your vitamin B12 levels checked prior to falling pregnant to ensure they are in the normal range. If you are already pregnant, ensure you are taking a supplement with adequate vitamin B12 rather than relying solely on fortified foods. And ask your doctor to check your vitamin B12 levels at least once during your pregnancy.

Long chain omega-3 fats (DHA and EPA)

DHA and EPA are difficult to obtain in adequate amounts on a plant-based diet. These fats are critical for the development of the human brain. Research has revealed that during pregnancy, increasing your intake of omega-3 fats may reduce the incidence of preterm birth, low birth weight, perinatal death, neonatal care admission and postnatal depression (Innis 2007, Middleton et al 2018, Markhus 2013). So it's important we pay some attention to it.

You may have heard that chia seeds, linseeds and walnuts contain omega-3 fats. This is correct, however these are the short-chain version (known as ALA). Although small amounts of ALA can be converted by our body into DHA, this conversion is very poor (less than 10%). So, although it is healthy to consume ALA-rich foods, plant-based eaters are encouraged to also take an algae-based DHA supplement.

Protein

Let's move onto protein. Protein is required to build new cells. During pregnancy, your body ramps up its production of new cells to grow your baby, the placenta, breast tissue and the uterus. Therefore, your protein requirements increase significantly. Protein is found in all plant foods in differing amounts. Despite the different amino acid make up and digestibility to animal protein, a carefully planned plant-based diet can meet your protein needs for pregnancy.

Plant proteins contain a mix of different amino acids, but not all of them contain the essential nine (which is why you may have heard the term "incomplete" proteins). This is nothing to worry about when if you eat a variety of plant foods over the day. There are in fact a handful of plant foods that are a "complete" (or close to) protein source. These include soybeans, spinach, buckwheat, quinoa, amaranth and hemp seeds. I'd recommend including some of these foods in your daily menu.

If you follow a plant-based diet, you may need to aim a little higher with your protein intake. The presence of fibre, along with anti-nutrients in plant foods, is responsible for the slightly lower digestibility of plant proteins compared to animal proteins (Messina 2001).

On average, pregnant women need between 70 - 120g of protein/day (depending on their size and gestation). Needs are lowest in the first trimester and increase with gestation. Although I don't encourage women to "count" their nutrients, it's wise to ensure you are including protein rich plant foods at every meal and snack.

Plant foods that are richest in protein include legumes, nuts, seeds, psuedo grains and soy products. Here are some protein tips:

Choose pseudo grains (quinoa, buckwheat, amaranth) in place of regular grains
Use a high protein plant milk (whole soybean milk)
Top your meals with a sprinkle of nuts and/or seeds
Add nut butter to your fruit
Snack on roasted chickpeas, bliss balls, nuts or hummus
Include legumes or unprocessed soy foods at all of your main meals
Use almond meal, hemp seed meal or sunflower seed meal in your baking
Protein powders may be useful for some women (individual advice is recommended)

Iron

Meeting your iron needs in pregnancy is difficult whether you follow a plant-based diet or not. Your body needs extra iron to account for the increase in blood volume and so that your baby can lay down its own iron stores.

There are two main forms of dietary iron, haem iron (found in animal foods) and non-haem iron (found in plant foods). Non-haem iron is not as well absorbed by the body, so if you follow a plant-based diet you need to be aiming for a higher intake. Research suggests this could be as high as 1.8 times the RDI (IOM 2001). So, is it possible to meet these requirements from food? That's a good question that depends on many factors. Iron absorption is complex and it’s not only a matter of how much iron we consume, but more a matter of how much iron our bodies can absorb. What we do know is that our iron stores prior to falling pregnant are important. If you enter pregnancy in a depleted state, it is more likely you will end up suffering from iron deficiency/anaemia.

If you are wishing to conceive in the near future, now is the time to really focus on your dietary intake of iron and get some blood tests with your GP. Depending on your iron levels, you may need supplements in addition to food to increase your iron stores (boosting iron stores is much easier to do prior to falling pregnant). There are so many forms of supplemental iron, and I can tell you from years of experience that not all of them make you constipated. A prenatal dietitian can assist you with this.

Calcium

Calcium is required for skeletal development and the functioning of nerves and muscle. If your dietary intake of calcium is low, your body will leach it from your bones to ensure there is enough for your baby. We don't want your bones becoming brittle, so it's important you are meeting your calcium needs.

There are so many wonderful plant foods that naturally contain calcium. Just keep in mind that some of these foods do not contain high amounts of calcium on their own, so it's essential you include them regularly over the day. Calcium fortified plant-based milks are helpful too, however not all plant-based milks are fortified with calcium so it's important to check the label (many 'barista' milks are not fortified). If you are relying on fortified milk to meet your calcium needs, look for those that contain 300 mg calcium per 250ml serve (120 mg per 100 ml) which is similar to the calcium content of cows milk. Always shake your milk before use, as the calcium tends to settle on the bottom.

The RDI for calcium in pregnancy is 1000 mg/day (NHMRC 2006). If you follow a plant-based diet it is recommended to aim for 1200 mg to account for the lower absorption of calcium from plant foods. Despite this increase, it is rare that I need to prescribe a calcium supplement to a pregnant client who follows a plant-based diet. Most of the time a few simple switches will get them where they need to be. However, if you don't think you are able to achieve this, speak with a prenatal dietitian, nutritionist or GP about your supplement options. Please note that most prenatal multivitamins do not contain much calcium. Check the label of your products to see how much you are getting.

Choline

Choline is not as well known as other nutrients, only recognised as an essential nutrient in 1998. Current research on choline and it's role in pregnancy is fascinating, as it plays a significant role in foetal brain and neural development. Higher maternal intakes of choline have been shown to reduce the risk of pre-eclampsia, low birth weight and NTDs (Wallace et al. 2018).

The optimal amount of choline that is needed in pregnancy is not well known. It is thought that our current guideline of 440mg is not sufficient to meet the demands of pregnancy (Wallace et al. 2018). Some research suggests that 930 mg of choline in the third trimester of pregnancy has a beneficial effect on foetal development, placental function and brain function in children (Jiang et al. 2013, Caudill et al. 2018).

Although choline is found in many plant foods, it can be difficult to reach upwards of 440 mg a day. I would therefore consider supplementing with choline on top of eating choline-rich plant foods. It would be best to start supplementing 1 month prior to conception (just like the recommendation for folate). Most prenatal multivitamins do not contain choline, so it's important to check your label or supplement separately. If you would like some assistance with supplements, you can book a supplement consult here.

Iodine

Iodine is a key component of thyroid hormones that are needed for foetal brain development. Luckily, the richest source of iodine is seaweed! However, if you don't eat seaweed, there are not many other plant foods that contain large amounts of iodine.

If you are a seaweed lover, it's important to know which seaweeds to eat in pregnancy, as some have extremely high levels of iodine that could be detrimental if you were to eat them every day. Nori is the lowest in iodine, and can therefore be consumed daily. Wakame and dulse have a moderate iodine level, so these are great to include a few times a week. Kombu and kelp are much higher in iodine - that's not to say they need to be avoided, but you would only want to have small amounts.

If you don't eat seaweed regularly, a supplement is required. If you are taking a prenatal multivitamin, it will most likely contain a minimum of 150 mcg iodine in the daily dose, which is the recommended amount set by the Royal Australian and New Zealand College of Obstetrics and Gynaecologists (RANCOG 2020). Another way to increase your iodine intake is by using iodised salt. If you are relying on iodised salt, make sure you seal the container well and store at a low temperature as iodised salt can lose its iodine content via oxidation if left in warm and humid conditions.

My top tips for plant-based women in pregnancy:

Base your meals around nutrient-dense plant foods such as legumes, wholegrains (in particular pseudo grains - quinoa, buckwheat, amaranth), nuts, seeds, avocado, fruits and vegetables
Get out in the sun regularly for your vitamin D
Include seaweed (nori, wakame, dulse) regularly in your diet for iodine
Limit processed foods (vegan processed foods are just as bad as regular processed foods)
Soak your grains and legumes if you have the chance (soaking guide can be found in my book). This will help breakdown antinutrients (ie. phytic acid), which will allow you to absorb more iron, zinc and calcium from these foods.
Eat vitamin C with your meals to help with iron absorption (capsicum, oranges, lemon juice, broccoli, berries, tomatoes)
Aim for a higher intake of iron, zinc, calcium and protein to allow for the lower bioavailability of these nutrients in plant foods
Ensure you are supplementing with a minimum of vitamin B12 and omega-3 fats. Other common nutrients required in supplemental form include iron, iodine and choline.
See a prenatal dietitian for individual diet and supplement advice

References:

SM Innis, 'Dietary (n-3) Fatty acids and brain development', The Journal of Nutrition, 2007, 137(4):855–859, doi:10.1093/jn/137.4.855.
P Middleton, JC Gomersall, JF Gould et al., 'Omega-3 fatty acid addition during pregnancy', The Cochrane Database of Systematic Reviews, 2018, 11(11):CD003402, doi:10.1002/14651858.CD003402.pub3.
MW Markhus, S Skotheim, IE Graff et al., 'Low omega-3 index in pregnancy is a possible biological risk factor for postpartum depression', PloS One, 2013, 8(7), e67617, doi:10.1371/journal.pone.0067617.
Messina V., Mangels A.R. Considerations in planning vegan diets: Children. J. Am. Diet. Assoc. 2001;101:661–669. doi: 10.1016/S0002-8223(01)00167-5.
Institute of Medicine (US) Panel on Micronutrients, 'Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc', National Academies Press (US), 2001.
National Health and Medical Research Council. Eat For Health. Nutrient Reference Values for Australia and New Zealand, 2006.
TC Wallace, JK Blusztajn, MA Caudill et al., 'Choline: The underconsumed and underappreciated essential nutrient.' Nutrition Today, 2018, 53(6):240-253, doi: 10.1097/NT.0000000000000302.
Jiang X, Bar HY, Yan J, Jones S, Brannon PM, West AA, Perry CA, Ganti A, Pressman E, Devapatla S, Vermeylen F, Wells MT, Caudill MA. A higher maternal choline intake among third-trimester pregnant women lowers placental and circulating concentrations of the antiangiogenic factor fms-like tyrosine kinase-1 (sFLT1). FASEB J. 2013 Mar;27(3):1245-53. doi: 10.1096/fj.12-221648. Epub 2012 Nov 29. PMID: 23195033.
Caudill MA, Strupp BJ, Muscalu L, Nevins JEH, Canfield RL. Maternal choline supplementation during the third trimester of pregnancy improves infant information processing speed: a randomized, double-blind, controlled feeding study. FASEB J. 2018 Apr;32(4):2172-2180. doi: 10.1096/fj.201700692RR. Epub 2018 Jan 5. PMID: 29217669; PMCID: PMC6988845.
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists, Vitamin and mineral supplementation and pregnancy, HPS website, 2008 (amended 2015), accessed 1 September 2020.

Plant based pregnancy