DHA: a critical nutrient for the mother-baby dyad
DHA is the abbreviation for the omega-3 fatty acid called docosahexaenoic acid and is the sister of eicosapentaenoic acid (EPA for short). The omega-3 fatty acids are nutrients and can be found in both whole foods and supplements. This article will help you to understand DHA and explain how you can use DHA to your advantage in both pregnancy and post-partum.
Why is DHA recommended in pregnancy?
DHA is recommended due to the extremely high demand for omega-3 fatty acids in the pregnant body. You are constructing a human being from scratch. Every single body part; from the bones to the heart of your little one must be made using the resources available within you – the mother. Each teensy tiny baby part is made up of many, many cells. The miracle unfolding in the womb is essentially a cascade of exponentially multiplying cells. Millions and billions of cells which all of which must have a membrane to keep the inside of the cell separate to the outside. Human cell membranes contain two layers of fats called a phospholipid bilayer. DHA is used within the structure of the phospholipid bilayer. This is to say that DHA is embedded within the membrane of every cell in the human body. Billions of cell membranes, all needing DHA to ensure that the cells can do their job to maintain life and grow. The cells that make up the brain, nerves and eyes are especially rich in DHA, which is why DHA status is linked to vision, cognition and nervous system health.
Does DHA prevent early preterm labour?
Early preterm labour refers to birth before <34 weeks gestation. Tragically, it is the leading cause of death in babies. I say this not to scare you, more to emphasise how crucial DHA is for a healthy full term pregnancy, and how DHA status is such an easy risk factor to modify. A Cochrane review by the University of Adelaide determined that DHA supplementation in pregnant women could reduce the risk of early preterm birth by 42% (a significant reduction). Lower rates of early preterm birth also means far fewer admissions to the NICU, fewer babies born at a low birth weight and fewer perinatal deaths. Of course, another result is a lot less trauma, stress and heartache for both babies and families who experience early preterm birth.
The review found that women who had a blood DHA level of 5% or less, were the most likely to benefit from DHA supplementation for the purpose of preventing early preterm birth. These same women were dosed with supplemental DHA at the upper end of the dosage range. They were given up to 1000mg of DHA, appropriate to their level of deficiency.
In English, this means that a blood DHA level of less than 5%, can significantly increase the risk of early preterm birth. According to the review, the greatest risk reduction occurs in women who increase their blood DHA from <5%, to 5-6%. Not a huge change given the impact on outcome.
For context, it is estimated that only 20% of women will enter pregnancy with a DHA level of 5%, the bare minimum to avoid that higher risk of early preterm birth. That leaves 80% of women entering pregnancy with a less than ideal DHA level.
What does it take to maintain a DHA level of 5% from diet alone?
Women who consume fish (especially fatty fish) twice a week can expect to have a blood DHA level of about 5%. That’s a dietary intake of 100mg DHA per day. In reality, most women are consuming around half that, at 50mg.
To counter the low average intake of fish in modern western populations, the recommendations for pregnant women includes 200mg of supplemental DHA, to complement the 100mg acquired through diet. That’s a total of 300mg from food and supplements to achieve and maintain a blood DHA level of 5-6%.
For a more drastic improvement of blood DHA level, a higher dose is required. In the case of a pregnant woman who does not regularly consume fish and who is confirmed to have a blood DHA of less than 5%, a dose of 1000mg DHA per day may be appropriate. At that stage, it is a game of catch up to achieve that higher blood level of DHA.
Can I get DHA from plants?
For vegans and vegetarians, plant foods are a potential source of omega-3 fatty acids – but they are an indirect source. Plants don’t actually contain omega-3 fats, they contain something called alpha-linoleic acid, which the body has to convert into EPA and DHA (the omega-3 fatty acids)
Imagine that you’ve eaten a handful of walnuts. A handful of walnuts contain about 2000mg of alpha-linoleic acid. Sounds good, right? Now the body has to take that 2000mg and convert it into omega-3 fatty acids. But that process isn’t hugely efficient and so it is estimated that less than 4% will be turned into DHA. So, 4% of 2000mg is 80mg. That means that a handful of walnuts will get you about 80mg of DHA, without accounting for potential genetic variations.
In comparison, an 85g can of wild Alaskan salmon contains about 600mg of straight DHA.
In short, yes the body can use plant based fatty acids to create DHA and EPA in the body, but it is a relatively inefficient process. These foods simply do not yield as high a volume of DHA or EPA omega-3 fatty acids as animal foods.
What about marine algal oil?
Algal oil is a vegetarian source of DHA taken as a supplement. It is produced from microalgae and is a true vegetarian source of pre-formed DHA, meaning that the body does not need to convert DHA from ALA in order to use it. It’s ready to go.
A high quality prescription-only algal supplement will provide about 600mg DHA per daily dose, and costs about $2 per day. I highly advise all women who are pregnant or trying to conceive, invest in a quality algal oil supplement to ensure they are meeting the requirements for DHA.
DHA deficiency and baby brain
Most mothers have used the concept of ‘baby brain’ at some time to explain weird faux pas or basic human error in the months after welcoming a babe. I once left the bathroom tap running after washing my hands and flooded our apartment! Of course, becoming a parent changes the brain in more ways than one, but I believe a part of the ‘baby brain’ phenomenon may be due to the preferential transfer of DHA from the mother to the baby either across the placenta in pregnancy or in breastmilk. DHA is so crucial for the developing baby that the mother’s body will give over whatever excess DHA is available, while keeping only the bare minimum for the mother’s functioning. Given that the vast majority of DHA is stored in the brain, it isn’t a far stretch of the imagination to expect that the brain might be a little under functioning in times of such extreme DHA demand. Then there is sleep deprivation and the other known brain changes that occur during the transition from maiden to mother.
Breastfeeding mothers are especially difficult to raise blood levels of DHA in. Even with supplemental dosages at the higher end of the spectrum, their blood DHA rarely moves above 5%, indicating that any excess DHA is moving across into the nursling. Much of a child’s brain and neural development occurs in the first two years of life, requiring a large amount of DHA which has got to come from somewhere.
How to get enough DHA for pregnancy and breastfeeding?
If we are being super thorough, checking on your red blood cell level of DHA is the first step. This is to establish a baseline and make sure that the dosage of DHA is correct for you as an individual.
Once we have your DHA level, we can assess your diet to see how much DHA you are getting from food and where there are any gaps that need to be filled. A good quality supplement is an easy way to ensure your DHA needs are met, especially if you find fish difficult to access, prepare or eat. Good quality supplements are also processed in such a way to remove contaminants, are tested for heavy metals and other impurities. A good quality supplement will often also contain an antioxidant source to help prevent the fish oil from going rancid.
How to test DHA levels…
Your average GP probably isn’t going to request this test for you, which means that you’ll need to go through a private lab. The easiest way to do this is through a Naturopath (aka me) who can order the blood test for you but also interpret the results and guide you through any dietary or supplementary interventions. At the time of writing, an Essential Fatty Acids (Red Blood Cell) test costs about $131AUD and will provide information on your DHA red blood cell level as well as omega-6, omega-9, and other essential fatty acid percentages and ratios. Super comprehensive!
Eating more fish in pregnancy & concerns about mercury levels
In general, the nutritional benefits of consuming fish and seafood outweigh concerns about mercury content, even in pregnancy. Choosing sources of fish which are high in omega-3 and comparatively low in mercury is an easy way to go. Salmon, sardines, mackerel, anchovies, trout, mussels and oysters are great options as they are accessible as canned options if not available fresh. Mercury accumulates in the flesh of larger fish – fish that eat smaller fish for breakfast! So the smaller ocean dwelling fish listed above are the best options. Eating these foods twice a week is not going to cause mercury poisoning, but it is going to significantly bump up your DHA intake.
TLDR?
You need a lot of DHA for the health of you and your baby – from preconception to breastfeeding and beyond. Unless you are eating seafood 2-3 times a week and have done for years, you likely aren’t getting enough. Getting sufficient DHA is critical for the structure and function of your baby’s brain, eyes and nervous system. It also helps to prevent early pre-term labour. Consider a quality omega-3 supplement such as fish oil or algal oil that contains at least 200mg DHA per dose. My pick for an over the counter DHA supplement is Nordic Naturals Complete Omega liquid.