The short answer is “yes”, but it ultimately depends on your goal. For the purpose of covering the minimum amount of omega-3 fatty acids required for general health, it’s not necessary to consume fish or fish oil; you can just eat flaxseed.
Flaxseed is a rich source of alpha-linolenic acid|alpha-linolenic acid (ALA), the only essential omega-3 fatty acid (i.e., the only omega-3 that can’t be synthesized by the body). Following ingestion, ALA is converted into the longer chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the same fatty acids found in fish oil.
Animal-based foods are the primary sources of EPA and DHA in the diet. Consequently, vegetarians and vegans consume trivial amounts of these omega-3 fatty acids,[1] and their blood levels of EPA and DHA tend to be lower than meat-eaters'.[2]
Despite the near exclusion of EPA and DHA from plant-based diets, these diets are not associated with adverse health effects or impairments in cognitive development,[3] which suggests that the average ALA intake of people following these diets allows for sufficient endogenous synthesis of EPA and DHA. Furthermore, the consumption of a healthy plant-based diet is associated with a variety of health benefits, such as a reduced risk of chronic diseases like cardiovascular disease and type 2 diabetes.[4]
However, while it’s evident that the average person can cover their basic omega-3 fatty acid needs through ALA-rich foods (like flaxseed) alone, that doesn’t mean that ALA-only intake is optimal, at least with respect to certain health outcomes.
Higher intakes of EPA and DHA are associated with a number of health benefits,[5] and higher blood levels are, too. A higher blood level of EPA and DHA is associated with a reduced risk of all-cause mortality and death from cardiovascular disease or cancer,[6] as well as a reduced risk of developing type 2 diabetes.[7] Higher blood levels of EPA and DHA might also be protective against cognitive decline and dementia,[5] but more high-quality studies are needed to confirm whether this is the case.
Only consuming flaxseed may mean missing out on the potential benefits of higher-than-adequate levels of EPA and DHA, because the available evidence suggests that supplementing with ALA does not significantly increase the blood level of EPA and DHA.[8][9] (To be more specific, supplementing with ALA seems to increase the blood level of EPA to a small degree, but it either doesn’t affect or even slightly decreases the blood level of DHA, typically resulting in no effect on the combined level of EPA and DHA.[10])
As such, to maximize certain health outcomes, it might be best to consume direct sources of EPA and DHA — either in the form of fatty fish or fish oil, or, for vegetarians and vegans, in the form of algal oil — but further research is needed to confirm this.[11]
References
- ^Nicole Neufingerl, Ans EilanderNutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic ReviewNutrients.(2021 Dec 23)
- ^Bonny Burns-Whitmore, Erik Froyen, Celine Heskey, Temetra Parker, Gregorio San PabloAlpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet: Do They Require Dietary Reference Intake/Adequate Intake Special Consideration?Nutrients.(2019 Oct 4)
- ^Burdge GCα-linolenic acid interconversion is sufficient as a source of longer chain ω-3 polyunsaturated fatty acids in humans: An opinion.Lipids.(2022-Nov)
- ^Wang Y, Liu B, Han H, Hu Y, Zhu L, Rimm EB, Hu FB, Sun QAssociations between plant-based dietary patterns and risks of type 2 diabetes, cardiovascular disease, cancer, and mortality - a systematic review and meta-analysis.Nutr J.(2023-Oct-04)
- ^Troesch B, Eggersdorfer M, Laviano A, Rolland Y, Smith AD, Warnke I, Weimann A, Calder PCExpert Opinion on Benefits of Long-Chain Omega-3 Fatty Acids (DHA and EPA) in Aging and Clinical Nutrition.Nutrients.(2020-Aug-24)
- ^William S Harris, Nathan L Tintle, Fumiaki Imamura, Frank Qian, Andres V Ardisson Korat, Matti Marklund, Luc Djoussé, Julie K Bassett, Pierre-Hugues Carmichael, Yun-Yu Chen, Yoichiro Hirakawa, Leanne K Küpers, Federica Laguzzi, Maria Lankinen, Rachel A Murphy, Cécilia Samieri, Mackenzie K Senn, Peilin Shi, Jyrki K Virtanen, Ingeborg A Brouwer, Kuo-Liong Chien, Gudny Eiriksdottir, Nita G Forouhi, Johanna M Geleijnse, Graham G Giles, Vilmundur Gudnason, Catherine Helmer, Allison Hodge, Rebecca Jackson, Kay-Tee Khaw, Markku Laakso, Heidi Lai, Danielle Laurin, Karin Leander, Joan Lindsay, Renata Micha, Jaako Mursu, Toshiharu Ninomiya, Wendy Post, Bruce M Psaty, Ulf Risérus, Jennifer G Robinson, Aladdin H Shadyab, Linda Snetselaar, Aleix Sala-Vila, Yangbo Sun, Lyn M Steffen, Michael Y Tsai, Nicholas J Wareham, Alexis C Wood, Jason H Y Wu, Frank Hu, Qi Sun, David S Siscovick, Rozenn N Lemaitre, Dariush Mozaffarian, Fatty Acids and Outcomes Research Consortium (FORCE)Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studiesNat Commun.(2021 Apr 22)
- ^Qian F, Ardisson Korat AV, Imamura F, Marklund M, Tintle N, Virtanen JK, Zhou X, Bassett JK, Lai H, Hirakawa Y, Chien KL, Wood AC, Lankinen M, Murphy RA, Samieri C, Pertiwi K, de Mello VD, Guan W, Forouhi NG, Wareham N, Hu ICFB, Riserus U, Lind L, Harris WS, Shadyab AH, Robinson JG, Steffen LM, Hodge A, Giles GG, Ninomiya T, Uusitupa M, Tuomilehto J, Lindström J, Laakso M, Siscovick DS, Helmer C, Geleijnse JM, Wu JHY, Fretts A, Lemaitre RN, Micha R, Mozaffarian D, Sun Q,n-3 Fatty Acid Biomarkers and Incident Type 2 Diabetes: An Individual Participant-Level Pooling Project of 20 Prospective Cohort Studies.Diabetes Care.(2021-May)
- ^Katie E Lane, Megan Wilson, Teuta G Hellon, Ian G DaviesBioavailability and conversion of plant based sources of omega-3 fatty acids - a scoping review to update supplementation options for vegetarians and vegansCrit Rev Food Sci Nutr.(2021 Feb 12)
- ^Dempsey M, Rockwell MS, Wentz LMThe influence of dietary and supplemental omega-3 fatty acids on the omega-3 index: A scoping review.Front Nutr.(2023)
- ^Baker EJ, Miles EA, Burdge GC, Yaqoob P, Calder PCMetabolism and functional effects of plant-derived omega-3 fatty acids in humansProg Lipid Res.(2016 Oct)
- ^Harris WSAchieving optimal n-3 fatty acid status: the vegetarian's challenge... or not.Am J Clin Nutr.(2014-Jul)