Essential fats play important roles in supporting good health. They provide energy, make up part of cell membranes, and help with the absorption of fat soluble vitamins. Of the various types of fatty acids there are two types that we need to get in our diets (AKA essential fatty acids), as our bodies cannot make them: linoleic acid and alpha linolenic acid (ALA). Our bodies can use these two fats to make Omega-6 fatty acids and Omega-3 fatty acids, respectfully. In this post, we will be focusing on Omega 3s.
While omega 3's provide us with energy, they also serve other purposes. Many recommendations on this nutrient are based on their potential benefits for heart health, brain function and anti-inflammatory properties. The 2 types of omega 3's that are primarily responsible for these benefits are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), and the most common recommended source for them is oily fish.
ALA is an essential omega 3, which you can find in plant based foods such as walnuts, flax seed, hemp seeds, flax seed oil, chia seeds, and canola oil. The human body is able to make DHA and EPA out of ALA, but this happens very slowly so there are some concerns that it might not be enough to meet requirements. For this reason, many health organizations recommend consuming oily fish regularly.
However, with these nutritional recommendations also comes caution. The bodies of water that these fish live in are polluted, most notably with mercury, as a result of human intervention on the environment such as mining and burning of coal. Mercury is listed in the top 10 most concerning chemicals for public health, and eating fish is the primary way that humans are exposed to it according to the WHO (1). High exposure to mercury can have harmful effects on the body, such as delayed development in foetus, infants and children, impaired neurological development, and cognitive impairment. The list can go on with environmental pollutants that can concentrate in fish (2).
Other concerns with using fish as a main source of omega 3's are overfishing and the devastation of marine ecosystems (3). Overfishing has resulted in a decline in fish populations around the globe. In addition, fish are being caught at a younger age which means that there are less of them able to reproduce, further complicating the issue. In fact, some estimate that if we all followed the suggested intake of fatty fish (i.e. 1-2 servings per week (4)), “world fish populations may eventually collapse by mid-century” (3).
So, what are we to do?
The good news is that there is a vegan source of DHA and EPA. Just like us, the fish get their nutrients from the what they eat, including omega 3's. Microalgae, consumed by fish and rich in DHA, is a safe alternative. Oil can be produced from the algae and used to make fish-free omega-3 supplements. It is also environmentally sustainable, and free from mercury and other environmental pollutants as it can be cultured. You can find plant based DHA and EPA in sea vegetables, supplements and foods fortified with DHA and EPA.
The research is not clear yet on whether or not a plant based diet benefits from DHA/EPA supplementation. At the end of the day, the decision comes down to personal preference, food budget and how much you are looking to optimize your diet. If you are interested in taking a supplement, aim for 200-300mg DHA (and possibly EPA) 2 to 3 times per week (5) . This can be from a capsule or a food that has been fortified with plant based DHA, such as certain soy milks, flax seed oils, and fruit juices.
There are also some easy steps that can be taken to optimize conversion of ALA to DHA and EPA (6):
Eat plenty of omega 3-rich foods such as flax seeds, flax seed oil, hemp seeds, and walnuts. Ensuring a rich supply of ALA can help to encourage your body to produce more DHA and EPA on its own.
Limit oils high in omega 6's (safflower oil, sunflower oil and corn oil). Large intake of these omega 6's can prevent your body from converting ALA to DHA and EPA.
Consume omega 6 containing foods mainly in their whole forms (such as soy foods, or sunflower seeds). There are innumerable benefits to consuming foods in their whole form, the way nature intended.
Avoid foods high in trans and saturated fat. These fats are non-essential, and can also harm heart health.
Although the world of nutrition can seem confusing, and at times overwhelmingly complex, it doesn't have to be. Every now and then take a step back and look at the big picture. Find ways to add some more omega 3 rich foods to your diet where you can, a small amount a few times a day can really add up in the long run (such as adding ground flax to your oatmeal, hemp seeds to your smoothies, or walnuts to a trail mix). If you are enjoying a variety of foods and including some good sources of omega's overall, you should have that part covered!
(2) Ruzzin, J. (2012). The secret story of fish: decreasing nutritional value due to pollution? British Journal of Nutrition, 108, 397-399.
(3) Green, J., Ashburn, S.M., Razzouk, L., Smith, D.A. (2013). Fish oils, coronary heart disease and the environment. American Journal of Public Health, 103, 1568-1576.
(5) Davis, B., Melina, V.(2013). Becoming Vegan. Book Publishing Company, Summertown Tenessey.
(6) Practice-based Evidence in Nutrition. (2014). Vegetarianism: Key Practice Points.