Plant-based Sources of Protein & Omega-3 EFAs

Disclaimer: The following suggestions are presented for informational purposes only, and are not intended, nor should be taken, as medical advice. Please consult your doctor if you require advice on natural or supplemental forms of Omega-3 essential fatty acids (EFAs).

Fish are a good source of Omega-3 EFAs, but plant-based, marine and non-marine sources are also available. Information on plant-based, marine sources of Omega-3 EFAs can be found in Marine Algae & Forage Fish under Solutions. This section outlines alternatives to fish protein and plant-based, non-marine sources of Omega-3 EFAs.


There are 11 different types of Omega-3 EFAs, but eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the most important. Alpha-linolenic acid (ALA) is a short-chain polyunsaturated Omega-3 EFA found in terrestrial plants, while EPA and DHA are long-chain polyunsaturated Omega-3 EFAs found in marine plants (algae) and animals (fatty fish). Like fish, we cannot produce Omega-3 and must obtain it from our food.

Because ALA is a precursor to both EPA and DHA, plant-based ALA can be converted to EPA and DHA in the body in small amounts, although the conversion rate is generally quite low, around 5% for EPA and 0.5% for DHA (Plourde & Cunnane 2007), or between 8–20% for EPA and 0.5–9% for DHA (Stark et al. 2008). The potential conversion rate may be higher in vegetarians and vegans (Welch et al. 2010), although further studies in actual conversion rates are needed. If the diet contains enough ALA-rich foods (between 2000mg – 4ooomg daily), some requirement for Omega-3 EFAs can be met (Davis & Kris-Etherton 2003).

Plant-based, non-marine sources of Omega-3 EFAs

The richest plant-based, non-marine sources of alpha-linolenic acid (ALA) are flaxseed, chia seeds and walnuts. These foods are best consumed in their whole ground form or as oil. Flaxseeds contain 22.8g ALA per 100g, chia seeds contain 17.8g ALA per 100g, walnuts contain 9.1g ALA per 100g, while flaxseed oil contains 53.4g ALA per 100g and walnut oil contains 10.4g per 100g (Rajaram 2014).

Other plant-based sources of alpha-linolenic acid (ALA) include nuts, seeds, pulses and legumes; and dark green leafy (kale, spinach), cruciferous (broccoli, cauliflower) and starchy vegetables (pumpkin, squash). Butternuts are a yellow-orange vegetable source of ALA, with 8.7g per 100g, while wild-grown Purslane Weed (Portulaca oleracea) is the richest green plant source of ALA, with 0.9g per 100g, and 0.01 mg per gram of EPA (Uddin et al. 2014).

The recommended ratio of anti-inflammatory Omega-3 EFAs and pro-inflammatory Omega-6 EFAs varies between countries, with an optimal ratio of 1:4 suggested for vegetarians, vegans and non-fish eaters (Davis & Kris-Etherton 2003), although Omega-6 EFAs from unprocessed foods may be a better choice than Omega-6 EFAs from processed foods.

Plant protein

Many foods rich in ALA Omega-3 EFAs are sources of high-quality, nutrient-dense, plant protein. Nuts, seeds, pulses and legumes; and dark green leafy, cruciferous and starchy vegetables provide additional bulk to a watery fruit and vegetable-based diet, while plant-derived oils, including olive oil, provide additional essential fats, texture and satiety.

Like Omega-3 EFAs, protein is essential for the human body, but it is not necessary to eat fish or animal protein at every meal, or even every day. A plant-based diet supplemented with small amounts of protein from land-based or marine animals provides ample protein.

Reducing or eliminating our consumption of fish means increasing our intake of animal and/or plant protein however, this may place additional pressure on alternative systems to provide food. This must be taken into consideration, as well as our unique nutritional needs, likes and dislikes, cultural and ethical values, financial limitations and environmental footprint.

© 2016 – 2021 Seafood Free September


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Uddin, M. K., Juraimi, A. S., Hossain, M. S., Nahar, M. A., Ali, M. E., & Rahman, M. M. (2014). Purslane weed (Portulaca oleracea): a prospective plant source of nutrition, omega-3 fatty acid, and antioxidant attributes. TheScientificWorldJournal, 2014, 951019.