Olive Oil vs Flaxseed Oil: Omega-3s, Heat and Which to Use
Olive oil vs flaxseed oil is less a contest than a comparison of two oils built for different jobs. On USDA FoodData Central's figures, read for this article, a tablespoon of flaxseed oil carries about 7.3 g of omega-3 alpha-linolenic acid (ALA) — roughly 80 times the 88 mg in a tablespoon of extra virgin olive oil. On omega-3, flaxseed oil wins outright, and we will not pretend otherwise. But that same omega-3 makes flaxseed oil fragile: it oxidises easily, belongs in the fridge, and should not be used for frying or roasting. Olive oil, mostly monounsaturated oleic acid, is the one that copes with the pan. This guide sets out the numbers, the research and a simple rule for which to use, and when.
For our own oil, see our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml).
The Short Answer
- Flaxseed (linseed) oil is the richest common kitchen oil in omega-3: USDA lists 53.4 g of ALA per 100 g of cold-pressed flaxseed oil, about 7.3 g per tablespoon.
- Extra virgin olive oil has only a trace of omega-3 — 0.651 g of ALA per 100 g on USDA's 36-sample average, about 88 mg per tablespoon — and 67.8 g of every 100 g is oleic acid instead.
- Neither oil contains EPA or DHA, the long-chain omega-3s in oily fish; the body converts ALA to them only to a very limited degree, below 15% according to the US Office of Dietary Supplements.
- Flaxseed oil is about two-thirds polyunsaturated fat, which makes it prone to oxidation: keep it cold and use it raw, never for frying or roasting.
- Olive oil is mostly monounsaturated and, as extra virgin, carries vitamin E and polyphenols, so it is the better choice for everyday cooking as well as dressing.
- Both have supportive human evidence: higher ALA intake is linked with lower cardiovascular mortality in cohort studies, and extra virgin olive oil was part of the Mediterranean diet tested in the PREDIMED trial.
- The practical answer for most kitchens is both: olive oil for the pan and most of your dressing, flaxseed oil in small amounts, cold, if you want plant omega-3.
What Is in Each Oil: The USDA Numbers
Both oils are pure fat, at 884 kcal per 100 g in USDA FoodData Central. The difference is the type of fat. We read the database entries directly for this article: "Oil, flaxseed, cold pressed" (SR Legacy, FDC 167702) and "Oil, olive, extra virgin" (Foundation, FDC 748608, an average of 36 analysed samples). USDA weighs a tablespoon of flaxseed oil at 13.6 g and of olive oil at 13.5 g.
| Per 100 g (USDA FoodData Central) | Flaxseed oil, cold pressed | Extra virgin olive oil |
|---|---|---|
| Saturated fat | 9.0 g | 15.4 g |
| Monounsaturated fat | 18.4 g | 69.2 g |
| — of which oleic acid (omega-9) | 18.3 g | 67.8 g |
| Polyunsaturated fat | 67.8 g | 9.07 g |
| — of which linoleic acid (omega-6) | 14.2 g | 8.4 g |
| — of which alpha-linolenic acid (omega-3) | 53.4 g | 0.651 g |
| EPA and DHA (long-chain omega-3) | 0 g | 0 g* |
| Omega-3 per tablespoon | about 7.26 g | about 0.088 g |
*From USDA's olive oil entry FDC 171413, which records zero EPA, DPA and DHA.
The table explains everything that follows. Flaxseed oil is a polyunsaturated oil dominated by omega-3; olive oil is a monounsaturated oil dominated by omega-9. Flaxseed oil's omega-6 to omega-3 ratio is about 1:4, unusually tilted towards omega-3, while olive oil's is about 13:1 — though at under a tenth of its fatty acids, olive oil's polyunsaturated fat is small either way. Our article on olive oil's omega-3, 6 and 9 works through its full profile per tablespoon.
Omega-3: Flaxseed Oil Wins, by About 80 Times
On omega-3, there is no contest. One tablespoon of flaxseed oil supplies about 7.26 g of ALA, the same figure the US Office of Dietary Supplements gives in its omega-3 fact sheet, where flaxseed oil heads its table of ALA sources. The US adequate intake for ALA is 1.6 g a day for adult men and 1.1 g for adult women, so a single tablespoon provides roughly four to six times the daily amount. A tablespoon of extra virgin olive oil provides about 5–8%.
Two qualifications keep that win in proportion. First, ALA is a short-chain omega-3. Most omega-3 research on heart and brain health concerns EPA and DHA, from oily fish and algae, and the Office of Dietary Supplements notes that the body converts ALA to EPA and DHA only to a very limited degree, with reported rates below 15%. Flaxseed oil is an excellent ALA source, not a substitute for long-chain omega-3. Second, more is not automatically better: once ALA needs are met, a second or third tablespoon adds energy without a clear extra benefit.
If long-chain omega-3 is what you are after, our comparison of olive oil vs fish oil covers that question.
Heat: Why Flaxseed Oil Stays Out of the Pan
The fat that makes flaxseed oil rich in omega-3 is the same fat that makes it fragile. Polyunsaturated fatty acids react with oxygen far more readily than monounsaturated ones, and ALA, with three double bonds, is among the most reactive fats in the kitchen. In a 2026 study in Food Chemistry, Vera-Candioti and colleagues describe flaxseed oil as "highly susceptible to oxidation" [5]. Heat, light and air all speed the process, and oxidised flaxseed oil tastes bitter and smells of paint.
That is why flaxseed oil is sold for cold use. Producers typically sell it refrigerated in dark bottles and advise keeping it in the fridge and using it within weeks of opening. Use it in dressings, stirred into porridge or yoghurt, or drizzled over finished food — never for frying, roasting or baking at high temperature.
Olive oil is the opposite case. About three-quarters of its fat is monounsaturated, and extra virgin oil carries natural antioxidants: USDA's olive oil entry lists 14.4 mg of vitamin E (alpha-tocopherol) per 100 g, against 0.47 mg in flaxseed oil, alongside the polyphenols that cold-pressing protects. Flaxseed oil does carry its own protection, about 28.8 mg of gamma-tocopherol per 100 g, but not enough to make it a cooking oil. Our guide to olive oil at high heat covers what actually happens to olive oil in the pan.
One safety note on names: in the UK flaxseed oil is often sold as linseed oil, but "boiled linseed oil" from a hardware shop is a wood finish, not a food. Only buy linseed or flaxseed oil sold as food.
What the Health Research Says About Each
No trial has compared flaxseed oil with olive oil head to head in people, so each has to be judged on its own evidence. Both have real support, and both have limits.
Flaxseed oil: the evidence on ALA
The evidence for flaxseed oil comes largely from studies of ALA intake rather than of the oil itself. In a 2012 meta-analysis in the American Journal of Clinical Nutrition, Pan and colleagues pooled 27 studies of 251,049 people and found a 14% lower cardiovascular risk (RR 0.86) in those with the highest ALA intake or blood levels, with considerable variation between studies [1]. A larger 2021 dose-response meta-analysis in the BMJ, by Naghshi and colleagues, covered 41 cohort articles and nearly 1.2 million participants: each extra gram of ALA a day was associated with 5% lower all-cause and cardiovascular mortality, while high versus low intake was also linked with a slightly higher risk of cancer mortality (RR 1.06) [2]. These are observational findings — associations, not proof of cause.
Olive oil: a randomised trial and long cohorts
Olive oil's evidence includes a large randomised trial. In PREDIMED, Estruch and colleagues (New England Journal of Medicine, 2018) assigned 7,447 Spanish adults at high cardiovascular risk to a Mediterranean diet with extra virgin olive oil, the same diet with nuts, or a control diet; major cardiovascular events were lower in the olive oil group (hazard ratio 0.69, 95% CI 0.53–0.91) [3]. That tested a whole dietary pattern, not the oil alone. In US cohorts of 92,383 adults followed for 28 years, Guasch-Ferré and colleagues (Journal of the American College of Cardiology, 2022) found that eating more than half a tablespoon of olive oil a day was associated with 19% lower cardiovascular mortality than rarely or never using it [4].
Which Oil to Use for What
Use extra virgin olive oil for cooking — sautéing, roasting, shallow frying — and for most dressings and drizzling. Use flaxseed oil only cold, in small amounts, when you want plant omega-3: a spoonful in a dressing, smoothie, porridge or over finished food. Keep flaxseed oil in the fridge and never heat it.
| Kitchen job | Reach for | Why |
|---|---|---|
| Sautéing, roasting, shallow frying | Extra virgin olive oil | Mostly monounsaturated fat, with vitamin E and polyphenols to protect it |
| Salad dressings | Either, or a blend | Olive oil for flavour; a spoonful of flaxseed oil adds ALA |
| Smoothies, porridge, yoghurt bowls | Flaxseed oil | Cold use only, where its mild nutty taste disappears |
| Drizzling over hot finished food | Extra virgin olive oil | Stable and full of flavour; add flaxseed oil only once the food is off the heat |
| Baking | Extra virgin olive oil | Flaxseed oil is not meant to be heated |
| Daily plant omega-3 | Flaxseed oil | About 7.3 g of ALA per tablespoon, against 88 mg in olive oil |
For how both oils rank against every other common kitchen oil, see our guide to the healthiest cooking oil.
Three Fair Objections
"Flaxseed oil has 80 times the omega-3, so it must be the healthier oil." On omega-3 it is the better oil, and we say so. But "healthier" depends on the job. An oil that oxidises in the pan is a poor cooking fat, and olive oil's evidence — including a randomised trial — rests on its use as an everyday fat, not on omega-3.
"Olive oil's omega-6 to omega-3 ratio of 13:1 is bad for you." The ratio sounds worse than it is. Olive oil's polyunsaturated fat is under a tenth of its fatty acids, so a tablespoon adds only about 1.1 g of omega-6. Your overall balance is set by your whole diet, and a spoonful of flaxseed oil or a handful of walnuts shifts it far more than switching cooking oils would.
"Why not just eat ground flaxseed instead of the oil?" That is a fair choice. A tablespoon of whole flaxseed provides about 2.35 g of ALA, according to the Office of Dietary Supplements, plus fibre the oil does not have. Whole seeds can pass through undigested, so grind them first. The oil is simply a more concentrated source of ALA.
How to Choose and Store Each
For flaxseed oil, buy small bottles of cold-pressed oil sold as food, ideally from a refrigerated shelf, in dark glass with a best-before date. Keep it in the fridge, use it within a few weeks of opening, and discard it if it smells bitter or of paint.
For olive oil, choose extra virgin rather than "light" or "pure", which are refined grades. Look for a harvest date, a named origin and dark glass, and store it in a cool cupboard away from the hob. Olive oil keeps far longer than flaxseed oil, but it still tastes best within a few months of opening. For a fuller walkthrough, see our guide to choosing a quality olive oil.
Why Sidr & Stone
We will not tell you our olive oil is an omega-3 food — no honest olive oil is, and flaxseed oil plainly wins on that measure. What we can offer is the oil that does the everyday work in your kitchen, made with care you can trace. Sidr & Stone's Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) is pressed from olives grown on our own family-owned farm on the plains outside Marrakech, Morocco.
- Single-estate — Sidr & Stone's olive oil comes from our own family-owned farm near Marrakech, and we control every step from tree to bottle, with no blending across origins.
- Rain-fed — our trees are not irrigated; they take what the season gives.
- Organically grown — no synthetic fertilisers, pesticides or herbicides are used (not yet certified; certification is in progress).
- Single harvest — a small, limited batch, picked when the fruit is ready; the current batch's harvest details are on the product page.
- Cold-pressed within hours of harvest — mechanical extraction only, to protect flavour, aroma and polyphenols.
- Unfiltered extra virgin — minimally processed, so it may show natural sediment, which is normal.
- 100% natural — a single ingredient, olive oil, with nothing added.
- Dark glass with a gold label — a 500ml bottle that protects the oil from light.
- 10% of profits to charity — a brand-wide commitment.
- Fulfilment in the UK, EU, and US.
The fatty acid figures in this article are USDA averages, not measurements of our batches; we will publish lab figures for our oil once we have a certificate on file. What we will say is that our oil is single-estate Moroccan, rain-fed, organically grown and cold-pressed within hours of harvest — the unrefined extra virgin kind that belongs in the pan and on the table, with flaxseed oil beside it in the fridge if you want the omega-3. For more on what cold-pressing protects, see our guide to olive oil polyphenols.
Frequently Asked Questions
Is flaxseed oil better than olive oil?
For omega-3, yes: flaxseed oil has about 7.3 g of ALA per tablespoon against about 88 mg in extra virgin olive oil. For cooking, no: flaxseed oil oxidises easily and should only be used cold, while olive oil is stable enough for everyday cooking.
Why can't you cook with flaxseed oil?
About two-thirds of flaxseed oil is polyunsaturated fat, mostly ALA, which reacts readily with oxygen when heated. Heating degrades the omega-3 and produces bitter, off-flavoured oil, so use it raw and add it after cooking.
Does flaxseed oil need to be refrigerated?
Yes. Keep it in the fridge, in its dark bottle, and use it within a few weeks of opening. Discard it if it smells bitter or of paint.
Can I mix flaxseed oil and olive oil?
Yes, for cold use. A dressing made mostly with extra virgin olive oil and a spoonful of flaxseed oil combines olive oil's flavour with flaxseed oil's ALA. Do not heat the blend.
Is Sidr & Stone olive oil a source of omega-3?
No, and we would not describe it as one. Like any genuine extra virgin olive oil, ours is dominated by oleic acid with only a trace of omega-3. If you want plant omega-3, pair it with flaxseed oil, walnuts or ground flaxseed.
Is flaxseed oil the same as linseed oil?
Food-grade linseed oil is the same oil as flaxseed oil — linseed is the common UK name. Boiled linseed oil sold for wood finishing is a different product and is not food.
Where can I buy single-estate extra virgin olive oil?
Look for a producer that names one farm and one origin and bottles in dark glass. Ours is available to pre-order from our limited single-harvest batch, with estimated shipping from November 2026 and fulfilment in the UK, EU, and US.
Is olive oil a medicine?
No. Olive oil is a food, not a medicine. It has a long traditional history — including being honoured in the Prophetic Sunnah — and a substantial body of modern research, particularly around polyphenols, cardiovascular health, and the Mediterranean diet pattern. It can be a worthwhile part of a healthy routine, but it does not cure diseases and is not a substitute for medical care. Be cautious of any olive oil marketed with specific disease-cure claims.
Final Thoughts
The honest verdict splits cleanly. Flaxseed oil wins on omega-3, by about 80 times per tablespoon, and the research on ALA intake is encouraging. Olive oil wins in the pan, on stability and flavour, and on the depth of human evidence for its use as an everyday fat. They are not rivals so much as two tools: one for heat and daily use, one for a cold spoonful of plant omega-3.
If you are managing a medical condition or have been advised to take omega-3 for a medical reason, follow that advice, and ask your doctor or a dietitian before changing it.
Our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) — rain-fed, organically grown and unfiltered — is available to pre-order now from our limited single-harvest batch, with fulfilment in the UK, EU, and US.
Our extra virgin olive oil is grown organically on our own single-estate farm on the plains outside Marrakech: we control every step from tree to bottle, and no synthetic pesticides, herbicides or fertilisers are used. It is not yet certified organic — certification is in progress, and we will publish it as soon as it comes through.
References
- Pan A, Chen M, Chowdhury R, Wu JH, Sun Q, Campos H, Mozaffarian D, Hu FB. α-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis. Am J Clin Nutr. 2012;96(6):1262–1273. PMID 23076616. doi:10.3945/ajcn.112.044040
- Naghshi S, Aune D, Beyene J, Mobarak S, Asadi M, Sadeghi O. Dietary intake and biomarkers of alpha linolenic acid and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of cohort studies. BMJ. 2021;375:n2213. PMID 34645650. doi:10.1136/bmj.n2213
- Estruch R, Ros E, Salas-Salvadó J, Covas MI, Corella D, Arós F, et al.; PREDIMED Study Investigators. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med. 2018;378(25):e34. PMID 29897866. doi:10.1056/NEJMoa1800389
- Guasch-Ferré M, Li Y, Willett WC, Sun Q, Sampson L, Salas-Salvadó J, Martínez-González MA, Stampfer MJ, Hu FB. Consumption of olive oil and risk of total and cause-specific mortality among U.S. adults. J Am Coll Cardiol. 2022;79(2):101–112. PMID 35027106. doi:10.1016/j.jacc.2021.10.041
- Vera-Candioti L, Negro E, Mancini SI, Bernal CA. Oxidative stability of flaxseed oil: effects of tocopherols, phytosterols and extraction conditions. Food Chem. 2026;502:147708. PMID 41475217. doi:10.1016/j.foodchem.2025.147708
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Oil, flaxseed, cold pressed (SR Legacy, FDC ID 167702); Oil, olive, extra virgin (Foundation, FDC ID 748608); Oil, olive, salad or cooking (SR Legacy, FDC ID 171413). Accessed 2 October 2026.
- National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. Accessed 2 October 2026.
Disclaimer: This article compares olive oil and flaxseed oil using USDA FoodData Central composition data, US Office of Dietary Supplements guidance and published research available at the time of writing; database values and research findings may change, composition varies between oils and batches, and readers should check current sources. Comparisons are made in good faith and in fair terms. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.