When it comes to fulfilling nutritional requirements, vegans and vegetarians have it tough. Getting some nutrients may seem such a challenge, especially those that usually come from animal-based sources. While plant-based sources for those nutrients exist, they may not have the same quality or quantity to offer as their counterparts.

Take docosahexaenoic acid (DHA), for instance. An omega-3 fatty acid essential for our hearts and brains, this nutrient is present in high amounts in meats, fish and other seafood. While studies show that the body can produce DHA from alpha-linolenic acid (ALA), a plant-based omega-3 fat, this conversion is very inefficient. Only 0.1 to 0.5 percent of the ALA you consume from foods like flaxseed, soybeans and walnuts is converted into DHA.

So what is DHA and why can’t we — especially vegans and vegetarians — do without this healthy fat?

The importance of DHA

DHA is a long-chain fatty acid (LCFA), which means it consists of 12 or more carbon atoms. Omega-3 fatty acids like ALA, eicosapentaenoic acid (EPA) and DHA are excellent examples of LCFAs, with ALA from vegetable oils, seeds, nuts, legumes and grains being the most abundant omega-3 in the human diet.

For decades, scientists have been studying these healthy fats, ascertaining their exact functions inside our bodies. Thanks to their efforts, we now know that ALA is useful for preventing cardiovascular diseases and is the “parent” fatty acid for the production of both EPA and DHA, while EPA from fatty fish like tuna, salmon and herring helps reduce depression symptoms as well as inflammation.

As for DHA, here’s what researchers have to say about its functions:

• DHA is important for the growth and functional development of the brain in infants.
• DHA is required for the maintenance of normal brain function in adults.
• A diet rich in DHA improves learning ability, while a deficiency in DHA is linked to learning deficits.
• The brain prefers to take up DHA over other fatty acids.
• The turnover of DHA in the brain is very fast.
• In older adults, lower DHA levels in the brain are associated with age-related cognitive decline as well as the onset of sporadic Alzheimer disease.
• Based on epidemiological studies, eating at least 200 mg of DHA from fish a day decreases the risk of sudden death from heart attack by 50 percent.
• DHA-rich fish oil lowers blood triglyceride levels, reduces thrombosis and prevents cardiac arrhythmias, or irregular heartbeat.
• DHA-rich fish oil has also been found to decrease the proliferation of tumor cells.
• DHA deficiency is linked to depression; it is also what links depression and heart attack.
• DHA has a positive effect on diseases like hypertension, arthritis, atherosclerosis, depression, adult-onset diabetes mellitus, myocardial infarction, thrombosis and some cancers.

DHA is found in cell membranes throughout the body and is important for nerve cell communication. It also accounts for 97 percent of the omega-3 fatty acids found in the brain and 25 percent of the brain’s total fat content.

Plant-based food sources of DHA and EPA

Algae are some of the most unlikely sources of nutrients you can find. And yet, they’ve turned out to be surprisingly good at helping people meet their nutritional needs. Today, many people enjoy eating different forms of algae, such as nori, seaweed, spirulina and chlorella, because of their nutritional benefits. For vegetarians and vegans, seaweed and algae are important sources of omega-3s. This is because they are two of the few plant-based foods that actually contain DHA and EPA.

Algae are an acquired taste, so you may be reluctant to try these omega-3 sources. Nori and seaweed are familiar foods, so they probably won’t cause as much apprehension as chlorella and spirulina. But these two are actually packed not just with the nutrients you need, but also with surprising health benefits. If you can’t get over how they taste, try taking them with your smoothies or a bowl of oatmeal. This will help mask their taste and allow you to enjoy their benefits.

Walnuts are exceptionally nutritious and make great snacks. A one-cup serving of raw walnuts can give you 3.3 g of ALA plus other important nutrients. But unlike algae, walnuts do not contain DHA and EPA, so you’re going to have to rely on your body’s ability to convert AHA into those two.

Like walnuts, kidney beans and edamame beans can only provide ALA. The former offers 0.10 g of ALA per half-cup, while the latter provides 0.28 g with the same serving size. Kidney beans are great for curries and stews, while protein-rich edamame beans can be boiled or steamed and eaten on their own.

Chia seeds, hempseeds and flaxseeds are all generous sources of ALA. Flaxseeds have the highest ALA content of the three, offering 6.7 g of ALA per tablespoon. Chia seeds have the second-highest ALA content, offering about 2.5 g of the nutrient per tablespoon. Hemp seeds, meanwhile, offer about 0.9 g of ALA per tablespoon.

A different marine source of DHA for vegetarians and vegans

Because vegans and vegetarians avoid fish and animal products, they tend to have lower omega-3 fat indices than people on non-plant-based diets. Compared with people who regularly eat seafood, especially DHA- and EPA-rich fatty fish, vegans and vegetarians have 50 to 60 percent lower blood levels of omega-3 fatty acid. Because of this considerable difference, a team of Korean and American researchers decided to study if it is possible to increase the DHA levels of vegetarians and vegans using algae as sources.

Microalgae are microscopic single-cell organisms commonly found in freshwater and other marine systems. They are naturally rich in DHA and EPA; in fact, most fatty fish get their high levels of omega-3 fat by eating marine microalgae or other fish that feed on these microorganisms. Today, scientists grow certain species of microalgae in the lab and extract their oils to make DHA and EPA supplements for people who don’t consume fish. According to them, these omega-3 biofactories can be made to produce more by simply manipulating their growth conditions.

For their study, the researchers reviewed published studies on the effect of DHA from non-animal sources on the omega-3 indices and blood DHA levels of vegetarians and vegans. They found three controlled trials and two cohort studies that all reported significant improvements in the DHA status of vegetarians and vegans after these participants took supplements made from non-animal sources of DHA.

Because of these findings, the researchers concluded that vegans and vegetarians can boost their DHA intake using supplements made from the oil of marine microalgae. Meanwhile, studies have yet to confirm if improving the omega-3 status of vegans and vegetarians could further reduce their already low risk of dying from heart disease.

Sources:

VeryWellMind.com

Healthline.com 1

Healthline.com 2

Healthline.com 3

FoodInsight.org

ScienceDirect.com 1

ScienceDirect.com 2

MedicalNewsToday.com

ScienceDirect.com