DHA in Pregnancy and Postpartum

When it comes to pregnancy, everyone’s quick to talk about folate and iron, but docosahexaenoic acid (DHA) often slips under the radar. DHA is a game-changer for both mum and baby, particularly for brain and eye development/health. Let’s dive into why it should be on your radar (especially if an expectant mother), how much to consume, and where exactly to get it from.

Firstly, what exactly is DHA?

DHA, or docosahexaenoic acid, is a type of omega-3 fatty acid that's a major building block of the brain and retina. It is incredibly important for egg and sperm quality, but most think of it as brain food for their baby. During pregnancy, especially in the third trimester, a mother’s DHA stores are heavily drawn upon by the growing baby. This is when the baby’s brain undergoes rapid development, so having enough DHA stores is crucial. During breastfeeding, DHA is passed through breastmilk to continue neurological development. Our bodies are incredibly efficient during pregnancy, prioritising the baby’s needs. If there’s not enough DHA in the diet, the body will pull it from the mother’s stores, potentially affecting her own health. That’s why it’s vital to keep those DHA levels topped up for both mum and baby, in pregnancy and postpartum.

A few studies have shown some truly amazing stats on DHA intake for maternal and foetal health outcomes. Babies whose mothers had higher DHA levels tend to have better cognitive function and visual acuity as they grow older. That’s pretty powerful when you think about it - what a mum eats now could impact her child’s brainpower for years to come. For mothers, adequate DHA intake has been associated with a reduced risk of postpartum depression. DHA is a common nutritional approach to depression all over the world. Given how common and challenging postpartum depression can be, this is a compelling reason to make DHA a priority.

How much DHA do we need?

The pregnancy RDI is 200-300mg per day of DHA (keeping in mind, the RDI is a bare minimum). Some think that getting enough DHA through diet alone can be tough, which is why many rely on supplements during pregnancy. But, when aiming for about 200-300 mg of DHA per day, this just means eating a 85g portion of fatty fish (~1400mg DHA) 2-3 x per week. It’s really not that much! However, consuming slightly above this is ideal during pregnancy and postpartum to really reap the plethora of anti-inflammatory, hormonal and cognitive benefits of DHA, like 3-5 x per week. 

So, where do we get our DHA fix?

Cold water fatty fish are the richest sources of DHA, like wild-caught sockeye salmon, mackerel, cod, sardines. Mussels and oysters are great sources too. Land animals when grass-fed naturally have higher omega-3 fatty acid content, such as pasture-raised eggs and grass-fed beef, but the amount is still quite small. 

But the best source per gram? Fish roe is incredibly abundant in DHA, containing 1.80-2.2 mg of DHA per gram, so 180-220 mg per 100g. This is quite significant. For context: 

• Fish roe has the highest DHA content at around 1.8-2.2 mg per gram.

• Mackerel is among the richest sources of DHA containing 1.5-1.6 mg per gram.

• Sockeye salmon has a moderate amount, ranging from 0.5-1.0 mg per gram.

• Oysters also provide a moderate amount of around 0.4-0.6 mg per gram.

• Pasture-raised eggs are a good non-seafood option, especially compared to conventional eggs, containing 0.12-0.15 mg per gram.

• Beef has a small amount of DHA, less than 0.01 mg per gram. 

Not everyone loves these foods, some prefer to be plant-based. So how do we go about this?

To put it bluntly, one cannot obtain adequate DHA levels from their diet without consuming these animal foods. Plant foods contain an omega-3 fatty acid called alpha-linoleic acid (ALA). ALA can convert to EPA and DHA in the body. However, the conversion rates are so miniscule that ALA intake through plant foods would not suffice, especially for pregnancy and lactation demands. This is why vegans and vegetarians are often deficient in DHA. One study (referenced below) found the conversion rate of ALA to DHA to be lower than 0.5%. Some studies say it can be up to 3%. Either way, a very small amount is converted!

So let’s take this information and apply it to a plant-based source of omegas, like flaxseeds -  which is explained and displayed so wonderfully with graphics by Dietician, Lily Nichols, found here. 

Flaxseeds contain around 1600mg of ALA in 1 tablespoon. In an ideal world, the conversion may be 3% of 1600mg, which is 48 mg of DHA. 

When comparing this to an 85g piece of salmon that contains 1400 mg DHA, you would need to consume 30 tablespoons of flaxseeds for the conversion to be equivalent. Now that’s a lot of flax! This is the same for chia seeds, and you need even more when it comes to walnuts and hemp seeds. While these foods are nourishing for different reasons, they just cannot be relied on as a source of DHA. 

So how do vegetarians and vegans consume enough DHA? They would need to supplement a quality, plant-based algae. Algae is the original source of DHA, and fish accumulate it by eating algae. By going straight to the source, you can still receive great benefits.

So let’s address the elephant in the room - mercury!

Many people, especially mothers-to-be, prefer to err on the side of caution when it comes to seafood and mercury. This is understandable, as mercury is a well known heavy metal toxin. This is why consuming smaller fish is ideal, as they are likely to retain much less mercury. Avoid consuming larger things like swordfish, shark, ray, tuna, orange roughy, etc. 

Whether you choose to include seafood is entirely your choice. It is a big topic, but here’s some food for thought… 

Heavy metals compete with minerals for space in the body, often leaving us minerally depleted. So if we stayed minerally replete, wouldn’t this help ensure our body doesn’t hold onto metals? Hmmm…

So how can we stay minerally replete? Many ways, but for the sake of this conversation, insert… seafood! It’s a bit of a catch 22 here actually. Often in foods where metals may be present (i.e. seafood), we also conveniently find an abundance of things like iodine, zinc and selenium - our beautiful trace minerals that fight metals for parking spaces in the body, often used to push metals out of the tissue for the body to excrete. Some things like this we will never truly understand, but nature is more clever than we realise. 

Did you consume fish during pregnancy? Did you take a DHA supplement, and notice you felt great from it? We would love to hear from you! 

We hope today's blog has given you some delicious insight into ways you can support yourself and your baby during pregnancy and postpartum, using the original medicine - food. If you need further information or individualised guidance on your preconception, pregnancy and postpartum journey, our clinicians would love to help you via a consultation. 

References

Brenna, J. T., Salem, N., Sinclair, A. J., & Cunnane, S. C. (2009). Alpha-Linolenic Acid Supplementation and Conversion to n-3 Long-Chain Polyunsaturated Fatty Acids in Humans. Prostaglandins, Leukotrienes and Essential Fatty Acids, 80(2-3), 85–91. https://doi.org/10.1016/j.plefa.2009.01.004

Coletta, J. M., Bell, S. J., & Roman, A. S. (2010). Omega-3 Fatty Acids and Pregnancy. Reviews in Obstetrics & Gynecology, 3(4), 163-171.

Mozurkewich, E. L., Clinton, C. M., Chilimigras, J. L., Green, D. E., Johnson, T. R. B., Marcus, S. M., & Romero, V. C. (2018). The Mothers, Omega-3, and Mental Health Study: A Double-Blind, Randomized Controlled Trial. BMC Pregnancy and Childbirth, 18(1), 261.

Nichols, L. (n.d.). Omega-3 DHA: The essential nutrient for pregnancy. Lily Nichols RDN. https://lilynicholsrdn.com/omega-3-dha/