Alpha-Linolenic Acid
Summary
ALA is the plant omega-3. Long-term trials show little or no effect on deaths or heart disease, with a possible small drop in arrhythmia (grade C), and 1.9 g/day did not reduce events after a heart attack. The body converts under 15% of ALA to EPA and DHA, and most US adults already meet the intake target.
Key facts
- The essential omega-3 fatty acid from plants; the body cannot make it[1]
- 1.6 g/day for men and 1.1 g/day for women; 1.4 g in pregnancy and 1.3 g when breastfeeding[1]
- US adults average 1.59 g/day (women) and 2.06 g/day (men) from food, meeting the AI[1]
- Less than 15% is converted to EPA and DHA; ALA supplements raise blood EPA but barely change DHA[1][6]
- Cardiovascular events (little or no effect, C); arrhythmia (small reduction, C); inflammation and blood fats (mixed, D)[2][3][4][5]
- The Alpha Omega trial was funded by the Netherlands Heart Foundation and others; Cochrane authors report no known conflicts[3][2]
- 3 graded human outcomes on this page
- October 10, 2026
How it works
ProposedALA is the parent omega-3 fatty acid. It is a fuel and membrane component and a limited precursor of EPA and DHA, the longer omega-3s linked to heart effects; whether ALA itself affects heart rhythm or inflammation is not established.[1][6][2]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Heart | Grade C | Mixed | Meta-analysis · n = 19,327 · 2020 | 2 rows |
| Heart risk factors | Grade D | Mixed | Meta-analysis · n = 1,183 · 2023 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Death, heart disease and cardiovascular events | Mixed | Grade C | Meta-analysis · n = 19,327 · 2020 Adults at varying cardiovascular risk (5 ALA trials lasting at least 12 months) Form: ALA-rich or enriched foods, supplements or dietary advice · Dose: Varied across trials · Duration: 12 months or longer Probably little or no effect on all-cause or cardiovascular death and coronary events (moderate to low certainty); may slightly lower cardiovascular events (RR 0.95, not significant) and probably slightly lowers arrhythmia (RR 0.73 in 2 trials, 4,912 people). | 32114706 (opens PubMed)Source [2] |
| Major cardiovascular events after a heart attack | No effect | Grade C | RCT · n = 4,837 · 2010 Adults aged 60–80 (78% men) with a previous heart attack on modern drug therapy Form: ALA-enriched margarine · Dose: About 1.9 g/day of added ALA (target 2 g/day) · Duration: 40 months ALA did not significantly reduce major cardiovascular events (HR 0.91, 95% CI 0.78–1.05); in women the reduction approached significance (HR 0.73, P=0.07). Adverse events did not differ. | 20929341 (opens PubMed)Source [3] |
| Inflammation, blood fats and blood pressure in overweight or obesity | Mixed | Grade D | Meta-analysis · n = 1,183 · 2023 Adults with overweight or obesity (19 RCTs) Form: ALA supplements or ALA-rich foods · Dose: Varied across trials · Duration: Varied across trials ALA lowered CRP, TNF-α, triglycerides and systolic blood pressure slightly versus placebo, but raised LDL cholesterol; no effect on IL-6, diastolic pressure, total or HDL cholesterol. | 37778442 (opens PubMed)Source [4] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Flaxseed (linseed) oil | Varies[1] | ALA is absorbed like other dietary fats; less than 15% is converted to EPA and DHA.[1] | No form-specific tolerance data in our sources.[1] | Richest common source: 7.26 g ALA per tablespoon |
| Whole foods (chia, walnuts, ground flaxseed, canola and soybean oil) | Varies[1][2] | No form-specific absorption data in our sources.[1] | No form-specific tolerance data in our sources.[1] | ALA-rich food interventions in long-term trials |
| ALA-enriched margarine | Varies[3] | No absorption data in our sources.[3] | Adverse events did not differ from placebo over 40 months.[3] | Alpha Omega heart attack trial (about 1.9 g/day) |
Studied doses, daily needs and limits
Doses studied in human trials ranged from ALA-rich foods and advice in year-long trials to about 1.9 g/day of added ALA in margarine for 40 months in the largest trial; the Cochrane review pooled trials of ALA-rich foods, supplements or advice lasting 12 months or longer.[3][2]
Intake reference: Adult Adequate Intake (AI), as ALA: 1.6 g/day for men and 1.1 g/day for women (ages 19+); 1.4 g/day in pregnancy and 1.3 g/day when breastfeeding. No UL has been set for any omega-3.[1] No UL for omega-3s; the cautions in the ODS fact sheet about bleeding and immune effects concern high doses of EPA and DHA, not ALA. NIH ODS fact sheet (updated August 22, 2025).
Recommended intake and upper limit by age and sex
| Age | Male | Female | Pregnancy | Lactation | Upper limit (UL) |
|---|---|---|---|---|---|
| 0–6 months (AI) | 0.5 g | 0.5 g | — | — | Not set |
| 7–12 months (AI) | 0.5 g | 0.5 g | — | — | Not set |
| 1–3 years (AI) | 0.7 g | 0.7 g | — | — | Not set |
| 4–8 years (AI) | 0.9 g | 0.9 g | — | — | Not set |
| 9–13 years (AI) | 1.2 g | 1 g | — | — | Not set |
| 14–18 years (AI) | 1.6 g | 1.1 g | 1.4 g | 1.3 g | Not set |
| 19–50 years (AI) | 1.6 g | 1.1 g | 1.4 g | 1.3 g | Not set |
| 51+ years (AI) | 1.6 g | 1.1 g | — | — | Not set |
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- People relying on ALA for EPA and DHA
- Vegans and others who eat no fish get little EPA and DHA from ALA because conversion is under 15%; ALA supplements barely raise blood DHA.[1][6]
- Raised LDL cholesterol
- In overweight adults, ALA supplementation slightly raised LDL cholesterol in a pooled analysis.[4]
- Men concerned about prostate cancer
- Observational studies conflict: a 2013 meta-analysis found no clear link between dietary ALA and prostate cancer risk.[7]
- Blood thinners
- The ODS bleeding cautions concern high-dose fish oil, not ALA, but anyone on warfarin adding large amounts of omega-3 supplements needs medical advice.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Safety
ALA from food and moderate supplements appears safe.
Food sources
| Food | Serving | Amount |
|---|---|---|
| Flaxseed oil | 1 tablespoon | 7260 mg[1] |
| Chia seeds | 1 ounce | 5060 mg[1] |
| English walnuts | 1 ounce | 2570 mg[1] |
| Flaxseed, whole | 1 tablespoon | 2350 mg[1] |
| Canola oil | 1 tablespoon | 1280 mg[1] |
| Soybean oil | 1 tablespoon | 920 mg[1] |
- Flaxseed oil7,260 mg
- Chia seeds5,060 mg
- English walnuts2,570 mg
- Flaxseed, whole2,350 mg
- Canola oil1,280 mg
- Soybean oil920 mg
How to read the label
- Label dose vs clinical doseThe adult AI is 1.1–1.6 g/day; the Alpha Omega trial added about 1.9 g/day, about what a quarter tablespoon of flaxseed oil provides.[1][3]
- Plant omega-3 is not fish oilLabels saying "omega-3" may mean ALA or EPA/DHA; ALA does not substitute for EPA and DHA because conversion is limited.[1][6]
- Food firstOne tablespoon of flaxseed oil (7.26 g) or an ounce of chia (5.06 g) exceeds the daily AI.[1]
Cost per studied dose, without the sales pitch
Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.
Cost per studied dose
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Frequently asked questions
Is ALA as good as fish oil?
No. The body converts less than 15% of ALA to EPA and DHA, and ALA supplements barely raise DHA.[1][6]
Does ALA protect the heart?
Long-term trials show little or no effect on deaths or heart disease, with a possible small reduction in cardiovascular events and arrhythmia.[2][3]
How much ALA do I need?
The AI is 1.6 g/day for men and 1.1 g/day for women; most US adults already get this from food.[1]
Which foods are high in ALA?
Flaxseed oil (7.26 g per tablespoon), chia seeds (5.06 g per ounce), walnuts (2.57 g per ounce) and ground flaxseed.[1]
Does ALA raise prostate cancer risk?
A 2013 meta-analysis of 12 observational studies did not confirm a link.[7]
Sources
- [1]Omega-3 Fatty Acids: Fact Sheet for Health Professionals (updated August 22, 2025). NIH Office of Dietary Supplements, 2025. fact-sheet
- [2]Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.. Cochrane Database Syst Rev, 2020. meta-analysis
- [3]n-3 fatty acids and cardiovascular events after myocardial infarction.. N Engl J Med, 2010. RCT
- [4]Effect of Alpha-Linolenic Acid Supplementation on Cardiovascular Disease Risk Profile in Individuals with Obesity or Overweight: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Adv Nutr, 2023. meta-analysis
- [5]Effect of dietary alpha-linolenic acid on blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials.. Eur J Nutr, 2018. meta-analysis
- [6]alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans.. Prostaglandins Leukot Essent Fatty Acids, 2009. review
- [7]Case-control and prospective studies of dietary α-linolenic acid intake and prostate cancer risk: a meta-analysis.. BMJ Open, 2013. meta-analysis
What changed
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Adversarial review pass: every evidence row re-read against its PubMed abstract. Official sources opened before citing: NIH ODS Omega-3 Fatty Acids fact sheet for health professionals (updated August 22, 2025), whose ALA AI table, intake data, conversion rate, food values, no-UL statement and fish-oil interaction note are transcribed here. Industry ties: Alpha Omega funded by the Netherlands Heart Foundation and others; Cochrane review MRC-funded with no known author conflicts; funding not stated in the other abstracts. Kept out: superseded 2018 Cochrane versions (30019766, 30521670; UpdateIn flags). Retraction, expression-of-concern, erratum and withdrawn checks on all 6 PMIDs: none flagged. Page set indexable. Independent browser review (4 parallel reviewers, every evidence row checked against its abstract and official sources on the Vercel preview) found: Cochrane ALA population line no longer applies the whole-review 12–88 month range; Alpha Omega dose shows the 2 g/day target.