DHA — The Essential Fatty Acid That Helps With Pregnancy, Brain Health, The Nervous System & More
During pregnancy it’s easy to become overwhelmed and inundated with information and well-intentioned advice. When working with nutrition clients who are trying to conceive or navigating that first-trimester emotional roller coaster, I help them stay calm and cut through the mixed messages and those anecdotal (and often unhelpful) tips that come from a good place but can be frustrating.
What is DHA?
Omega-3 fatty acids1 are considered essential nutrients, meaning that our body needs them but can’t make them on its own, so we have to get them from food or supplements. There are several types: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). These polyunsaturated fatty acids are a key component of cell structure, involved in energy production, and functions of our cardiovascular, endocrine, immune, and pulmonary systems. DHA, for example, is essential to proper formation and functioning of the brain, retina, and sperm.
Omega-3s are a vital nutrient in fetal development. DHA, in particular, is especially important during pregnancy because it helps build your baby’s nervous system, brain, and eyes. It’s also a component of breast milk, which helps ensure a newborn gets enough of this important nutrient to support development.
While many plant foods provide ALA1, which can then be converted to EPA and DHA in the body (though not necessarily very efficiently), you primarily find DHA in animal sources like cold-water fatty fish and fish oil. However, DHA is actually originally synthesized by microalgae, so algae and foods that contain it can help you consume more DHA on a plant-based diet.
How much DHA do you need?
Technically, EPA and DHA can be synthesized from ALA, so ALA is considered the only essential omega-3 fatty acid. Requirements for people more than 1 year old is expressed in grams of ALA. The National Institutes of Health recommends1 that healthy adult women consume 1.1 grams (or 1,100 milligrams) per day and that pregnant women consume 1.4 grams (or 1,400 milligrams) of ALA per day to meet their needs.
At present, there are no established requirements for DHA in pregnancy, but health professionals typically recommend2 that pregnant women aim for 650 mg total omega-3s per day, with 300 mg coming from DHA.
Foods that contain DHA.
Fish oils, krill oil, and fatty fish like salmon, tuna, mackerel, sardines, and anchovies are all good food sources of DHA, and eggs provide a little bit as well. DHA-fortified foods such as juices, milk, and grain products are also available.
Because you need to be careful about intake of mercury in fish during pregnancy, understanding which varieties are highest in mercury and spacing out your fish intake throughout the week is important. Familiarizing yourself3 with this list by the FDA that explains which fish tend to have more mercury can be helpful.
For example, having salmon, sardines, anchovies, or herring two to three times per week is considered safe, but you want to keep others such as albacore and yellowfin tuna to once per week. Swordfish, king mackerel, and big-eye tuna are varieties to avoid during pregnancy. In general, mixing it up is a good bet, both for avoiding mercury as well as for covering more nutritional bases and simply mixing it up to prevent boredom.
Vegan sources of DHA.
While there aren’t many plant-based sources of DHA, it can be found in marine microalgae4. There are a few types that have been noted for their omega-3 fatty acid content. Working a variety of sea vegetables5 into your diet such as kelp, dulse, nori, red and green algae, spirulina, and chlorella can help you work toward your needs. Since they all have varying amounts of the various omega-3 fatty acids, you should consume many types to avoid overdoing it on any one type (which can lead to missing out on important nutrients).
If you’re not super-familiar with sea vegetables, don’t stress! It’s actually very easy to work them into your day. A few things to try:
- Use dulse, wakame, or kombu to make a soup stock or add to soups. It will add a satisfying salty flavor and lots of nutrients.
- Add dulse chips (available in many grocery and health food stores) to soups, salads, stir-fries, eggs, and grain dishes. You can even sneak them into a smoothie.
- Make your own veggie sushi with brown or black rice, vegetables, and avocado.
- Add sea vegetables to salad—you can toss them right in with your other greens and veggies. A sesame-oil-based dressing is a delicious complement.
- Enjoy dried seaweed as a snack or get creative and make your own, similar to how you’d make kale chips.
- Make a seasoning combining your favorite savory spices with dried seaweed flakes. A few good ones to toss together: salt, garlic powder, and onion flakes. Sesame seeds make a nice addition as well. Enjoy experimenting!
While culinary algae oil is commercially available, it’s rich in monounsaturated fat and low in saturated fat but not a good source of DHA. It’s a great option to add to the rotation if you’re looking for a neutral-tasting high-heat oil, but you’ll need to get your DHA elsewhere. Supplementing with an algae-oil-based supplement6 can be super helpful, as it can be difficult to be consistent about getting the DHA you need from food alone during a vegan pregnancy.
Do I need a DHA supplement?
Many women choose to take a DHA supplement during pregnancy in order to meet their needs on a consistent basis without worrying about mercury content and other dietary constraints. I generally recommend this to my clients who are pregnant or trying to conceive as well as for women who are breastfeeding, as breast milk is how a newborn can get the crucial DHA they need.
Fish oil supplements are a convenient way to make sure you’re getting enough, but there are also algae-based supplements on the market if you prefer a plant-based supplement. There is a lot of variation between formulations, so talk to your health care provider about which supplement would be the best fit for you. The National Institutes of Health Dietary Supplement Label Database is also a good resource if you want to compare products.
It’s easy to overthink when to take that supplement, but in general, I recommend taking it at a time you’re most likely to remember to take it. For many, that’s when they take their prenatal vitamin. As is the case with vitamin D, you can also find prenatal vitamins that contain DHA to make it easier. Some women find that the DHA supplements have a fishy aftertaste or may cause some mild stomach discomfort if taken without food, so taking them with a meal can help.
In general, a good guideline to avoid overthinking is to consume two servings of low-mercury fish per week, plant sources of ALA like flax, chia seeds, and walnuts, and to take a DHA supplement. If you’re feeling overwhelmed or have more questions, talk to your doctor or a registered dietitian for personalized guidance.
One more thing to keep in mind.
Remember, pregnancy is a time when you’re adjusting to a lot of changes and juggling a lot of information—and emotions. Some weeks you are going to feel totally on it and on track, and others could feel like the complete opposite. Be patient with yourself.
To learn more about prenatal nutrition, check out our guide to prenatal vitamins and vitamin D during pregnancy.
Jessica Cording, M.S., R.D., CDN, is a registered dietitian, health coach, and writer with a passion for helping people streamline their wellness routine and establish a balanced relationship with food and exercise. She received her Masters of Science in Clinical Nutrition from New York University, and a dietetic internship at NewYork-Presbyterian Hospital. Her writing has been featured in Forbes and Shape. Her book, The Little Book of Game-Changers: 50 Healthy Habits for Managing Stress & Anxiety, offers simple hacks that help her patients and clients reach their goals and nurture their mental, physical, and emotional health, even when life becomes hectic.