Omega sounds like part of college Greek life, right? We’re talking here about Omega 3 fatty acids, which are essential to get as our bodies can’t make them. The most common ways we are advised to do so is through eating fish or supplementing with fish oil. The current dietary recommendation is to include one to two servings of fatty fish each week. Fishing is suggested to be unsustainable and environmentally damaging and along with other reasons that some people have for not consuming seafood or other animal-based sources, alternatives need to be addressed. Plant-based omega 3 fat sources are a solution, but are they as efficient in supplying what we need?
NOTE: This post is not intended to give dietary advice. Contact a registered dietitian if that is what you are seeking. Statements are my own or referenced from researched sources to share information helping people interested in plant-based alternatives to seafood. This post is not intended to disapprove of seafood businesses and organizations or one’s personal choice to consume seafood.
Fishing Is Suggested to be Unsustainable and Environment Damaging
Fish is commercially supplied for us to eat, for making fish oil supplements and for fish feed in aqua farming. The demand for fish and fish oil has risen to a point that it may threaten fish populations and the environments they live in. Waste from boats and pollution from land into the water can contribute and also threaten the quality and safety of seafood for consumers. While we don’t know yet to what degree the risk if any it poses to our health, fish are known to ingest or absorb plastic particles, chemicals and others contaminants in the water. Mercury is one concern, but there are many other residues that can become concentrated in their organs and flesh and pass up the food chain to accumulate in humans. That may not influence consumer decisions as much compared to concerns for animal welfare and a desire for sustainable sources.
Seafood suppliers and organizations have suggested more sustainable fishing practices. They encourage consumers to choose fish lower in the food chain more often and sustainable options described as fish with minimal environmental impact. However, the form of fishing described with the lowest environmental impact is hand caught or line fishing, which would be inefficient in supplying everyone with such fish. Sustainable seafood would rely on aqua farming for a higher yield, which is connected with the concerns people have that cause them to choose sustainable seafood in the first place. Not everyone has access to a local supply of fish either and this seafood would come at a higher price. Sustainable like traditional seafood policy also allows suppliers and menus to label fish simply as “fish” rather than the specific species.
Minimizing ocean damage from fishing to an extent that keeps the seafood industry thriving simply slows the damage rather than offer as solution to eliminate the cause of it. Understandably, some people enjoy fish and are allowed to eat what they want. Those interested in following a way of eating that does not include fish or animal sources of omega 3 fats based on environmental and health reasons or additional personal circumstances need alternatives to get omega 3s. Before addressing them, it’s important to first introduce the forms of omega 3 fatty acids, their roles and sources.
Different Forms of Omega-3 Fats Each with a Different Roles
Our bodies can naturally make some of the fats we need, except for omega-3 (and omega-6) fats, which must be obtain from food and are therefore called essential fats.
There are three main forms of omega-3 fats found in our food supply that we know of and each have different important roles in our bodies. Simply explained:
- Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are long-chain polyunsaturated fatty acids synthesized from short-chain fatty acids. They are found mostly in oily fish and in smaller amounts in other animal-based sources. Like omega-6 fats, their roles are to either make energy through oxidation or to integrate as phospholipids into cell membranes. They are precursors to molecules involved in the inflammation process and have a role in brain health.
- Alpha-linoleic acid (ALA) are short-chain polyunsaturated fatty acids that can be converted to the long-chain fatty acids. They are known to be found mostly in nuts and seeds, with the highest amounts being in flax, chia and hemp seeds, walnuts, vegetable oils, green leafy vegetables and certain fatty animal products that are grass-fed or omega-3 supplemented. They are involved in the inflammation process too and have a role in cardiovascular health.
Due to their different roles and benefits in the body, both EPA, DHA and ALA sources of food are recommended to be consumed.
The Conversion of ALA to EPA and DHA is Suggested to be Inefficient
ALA can be converted to EPA and DHA through a series of reactions involving enzymes and intermediates. This process has been suggested to be inefficient. What can make it inefficient?
One explanation is that there are rate limiting reactions that are the slowest and determine the overall rate or time, and therefore the efficiency, of the conversion pathway in forming products. The result is not all of the original reactant appears to get converted into the product and is used in other purposes. One such rate limiting step is the conversion of ALA to a higher intermediate that is catalyzed by the enzyme delta-6-desaturase.
Conversion can vary from person to person based on other factors, including gender and age as well as overall diet. Omega 6 fatty acids are known to compete with omega 3 fatty acids for some of the same enzymes, which can affect conversion rates too. Most studies have shown that adequate high doses of ALA can convert more efficiently to EPA, but conversion to DHA does not occur.
However, inefficient conversion from ALA is based on earlier studies performed using humans who consume fish or other direct sources of preformed EPA and DHA. Some have even suggested that the vegan and vegetarian diets observed tend to be low in ALA food sources. More studies have yet to be performed on vegans or people who do not intake direct sources of DHA from seafood, algae or other animal products and fortified foods and who intake enough ALA food sources (and adjust for the other factors addressed like individual differences and omega 6 intake). Only one such study has been performed so far and offers an insight into the Omega 3 conversion process and optimizing it through what we eat.
Conversion Is Likely More Efficient Without DHA Source
The EPIC-Norfolk Cohort Study on dietary intake and status of omega 3 fatty acids in fish-eating and non-fish-eating groups of people found that the reactant (ALA) to product (DHA) ratio was higher, suggesting higher conversion, among non-fish-eater vegans and vegetarians compared to fish-eaters.
These results can be explained by other studies that also look into the process at the cell and molecular level, including one suggesting ALA intake can adequately meet brain DHA requirements. Preformed DHA is suggested to cause the gene that expresses for the production of the enzyme elongase involved in the conversion process to turn off. Only in people who do not intake preformed DHA is the gene that produces the enzyme able to stay on and convert more ALA up through to DHA. It may be the body’s mechanism of signaling when it has enough DHA and doesn’t need to convert more ALA to DHA.
Understanding how we may be able to optimize the omega 3 pathway for better conversion to EPA and DHA in this way would be a huge breakthrough in dietary recommendations for plant-based non-fish eaters. Current recommendations include taking an algae-based omega 3 supplement, which contains DHA, though this may cause a similar inefficient conversion from ALA due to the direct DHA source. Another possible way to increase conversion would be to bypass one of the rate-limiting enzymes by including a food source that contains one the intermediates between ALA and EPA. In the next post, I will share this and other food sources of plant based omega 3 fatty acids.
Thanks for reading!