Fishing for Omega-3s: Seas & Seeds.
Omnivores and vegans alike should keep an eye on their essential fatty acids.
You have probably heard of essential amino acids, but did you know that certain fats are also essential ? These essential fatty acids must come from our diet because our bodies cannot make them.
Getting enough of the your essential fatty acids requires a bit of fishing, because they are not evenly distributed throughout nature (in contrast to essential amino acids).
This article cover all the basics on essential fatty acids:
- Which types of fats are essential?
- Why do we need these fatty acids?
- How much of them do we need?
- Which sources are best?
- Is more better?
Which types of fats are essential?
The only two types of fats that our bodies cannot make are omega-3 fatty acids and omega-6 fatty acids. These fats both belong to the polyunsaturated fatty acids (PUFA) family, a subset of unsaturated fats. PUFA fats are defined by the fact that they contain more than one double bond (in contrast to saturated fats, with no double bonds, and monounsaturated fats, with one double bond).
Nerd Note: Omega-3 and Omega-6 fatty acids are categorized as such based on the position of the first double bond relative to the methyl end of the fatty acid chain.
The names of specific omega-3 fatty acids can be quite a mouthful, so we typically use abbreviations (see cheatsheet below):
Nerd Note: DHA and EPA are technically considered conditionally essential fatty acids because our bodies can make them from ALA (though conversion rates can be very low).
Why do we need these fatty acids?
Essential fatty acids are critical components of cell membranes throughout the body, with DHA serving a special role in the retina, brain, and sperm. In addition, they provide energy for the body and are used to form signaling molecules (e.g. eicosanoids) which contribute to a range of functions including clotting and cardiovascular function.
How much of them do we need?
Most North Americans get plenty of omega-6 fatty acids, as they are abundant in animal products, in processed foods and oils used in fast foods.
Some health experts take a “less is more” approach to omega-6 fatty acids because recent research suggests that a lower ratio of omega 6 to omega-3 fatty acids is better, though more studies are needed [Review study].
In contrast, omega-3 intakes can be dicey, particularly when it comes to DHA and EPA. For this reason, the rest of this article focuses on omega-3 fatty acids. As we will see shortly, those who don’t eat seafood should be particularly careful.
The official North American Adequate Daily Intakes for omega-3 fatty acids vary with age and gender and increase during pregnancy and lactation [Institute of Medicine, summarized here]). The fact that they are considered “Adequate Intakes” and not RDIs (Recommended Daily Intake) speaks to the uncertainty around the numbers — these are really just “guesstimates”.
As for DHA and EPA, the longer chain PUFAs, there are no concrete daily targets in North America, because data are scant. Expert recommendations tend to fall around 250 mg of DHA. EPA appears to be less of a concern, provided one is getting ample ALA. [Sources: Vegan Health Review; European Food Safety Authority (EFSA)]
Which sources are best?
Getting enough ALA is easy, as many plants serve up large doses. Flax oil is the simplest and most economical choice: a single tablespoon gives 6x the adult daily intake (see table)! Other excellent bets are certain seeds (chia, hemp, flax) and different plant-based oils (soy oil, canola oil).
DHA and EPA are not as easy to knock out of the park as ALA. When it comes to foods, seafood stands out as your best bet, specifically the fattier choices. Fish oil supplements can also get the job done — be sure to read your label and focus on the DHA content.
Others, such as myself, choose not to eat seafood. If you fall in this camp, your best bet is an algae-based supplement. In fact, algae are the original omega-3 fatty acid source that fish rely on! My kids and I love NutraVeg liquid, though the tablet forms are cheaper.
Some people opt to shoot their ALA through the roof and count on conversion to DHA and EPA. I prefer to play it safe and do a bit of both.
One other source that I haven’t personally tried, is omega-3 enriched foods. Their greatest potential value is as a DHA source, as getting enough ALA is already so easy using plant-based oils and seeds.
Omega-3-enriched eggs contain between 75–250 grams of DHA (check the label!). Moderate levels are achieved by adding 10–20% flax to the hens’ diet, while higher levels are achieved by adding dietary fish oil. In contrast, conventional eggs contain a measly 30 grams DHA [Source: USDA Nutrient database).
Several plant-based milks are (theoretically) available in omega-3 enriched versions. Those with DHA may be worth considering depending on the levels (I couldn’t find any!) while those with ALA are likely not very valuable. I hope to see more plant-based DHA fortified foods on the market.
Is more better?
The goal of this article is to help you ensure that you are meeting your basic omega-3 fatty acid needs. The question of whether more is better is a hot topic in biomedical research, with complex data that warrant a fulsome discussion.
While most observational studies link higher fish intake with improved health, many trials of fish oil supplements have failed to deliver the same benefits. Some of the health outcomes under investigation include: cardiovascular health, brain health, and cancer. Data from randomized clinical trials are needed to shed light on these questions. Learn more from this great overview of omega-3s and health.
Early in human history, most of us probably met our omega-3 needs easily through abundant seeds and seafood. While our diets have changed significantly, many of our needs have not.
I hope that this article helps you to make sure that your modern diet still gets the job done, with or without fish (let’s hear it for algae!). There is no shame in using fortified foods and supplements to meet your needs, especially when they provide an essential nutrient.
I am formally trained in human genetics (PhD) and spent the first decade of my career working in cancer research, drug development, and personalized medicine.
This new chapter of my career is dedicated to empowering others to make evidence-based choices that are a win-win. I’m all about facts not fears, and love helping others to dial up their plants and dial down their animal products in a healthy way.
For more nutritional insights — and healthy, simple, recipes — check out my website (Fueled by Science).