Flaxseeds | whatsinit

About

What it is and where it shows up.

Flaxseeds are the small oil-rich seeds of Linum usitatissimum, cultivated and consumed for thousands of years as a whole food; they are exceptionally rich in alpha-linolenic acid (omega-3), dietary lignans, protein, and soluble fiber. They are consumed whole, ground, or cold-pressed into oil and are valued for cardiovascular, anti-diabetic, and anti-inflammatory health benefits.

Safety summary

The regulatory and scientific consensus.

Flaxseeds contain cyanogenic glycosides (chiefly linamarin and linustatin) that hydrolyze to release toxic hydrogen cyanide; the EU has responded by capping HCN content at 150 mg/kg in consumer-retail flaxseeds under Commission Regulation (EU) 2023/915. EFSA estimated that as little as 14.7 g of flaxseed per day could approach the Acute Reference Dose for cyanogenic glycosides, with children and adolescents at elevated risk at the 95th percentile of exposure. Long-term excessive consumption may also carry risks from phytic acid and phytoestrogenic lignans, especially in pregnant women, infants, and persons with thyroid disease.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Restricted	Commission Regulation (EU) 2023/915 of 25 April 2023 sets maximum HCN contaminant limits in flaxseed: 150 mg/kg for flaxseeds placed on the market for the final consumer; 250 mg/kg for unprocessed whole, crushed, ground, split, or chopped flaxseeds not sold directly to consumers. Based on EFSA CONTAM Panel scientific opinion (EFSA Journal 2019;17(4):5662).source
FSSAI (Food Safety and Standards Authority of India) (India)	Approved	Flaxseeds (locally known as alsi/tisi) are a permitted food ingredient under the Food Safety and Standards (Food Products Standards and Food Additives) Regulations, 2011. Naturally occurring toxins including cyanogenic compounds are governed by the FSS (Contaminants, Toxins and Residues) Regulations, 2011. Specific HCN numeric limits for flaxseed are not publicly specified in currently available FSSAI documents; general provisions for naturally occurring toxic substances apply.source
FDA (Food and Drug Administration) (United States)	Approved	Flaxseeds are whole food ingredients with a long history of safe use in the US food supply. They are not classified as a food additive and fall outside formal GRAS additive scheduling; no regulatory daily intake ceiling has been established. The FDA does not restrict flaxseed sale or use.source

Who should approach with care

Whose guidance would steer them away.

Infants — Infants are highly susceptible to hydrogen cyanide toxicity from cyanogenic glycosides; their low body weight means even small amounts of flaxseed can exceed safe HCN thresholds per EFSA's ARfD framework.

Children — EFSA's 2019 assessment found that children and adolescents may exceed the Acute Reference Dose for cyanogenic glycosides at the 95th percentile of dietary exposure from flaxseed-containing foods.

Pregnancy — Flaxseed lignans act as phytoestrogens and may exert weak estrogenic effects; combined with cyanogenic glycoside risks, high intake during pregnancy is not recommended without medical guidance.

Thyroid Disease — Flaxseed phytoestrogens (lignans) may interfere with thyroid hormone synthesis and metabolism; individuals with hypothyroidism or on thyroid medication should limit intake and consult a physician.

Ibs — The high soluble and insoluble fiber content of flaxseeds can exacerbate bloating, cramping, and altered bowel habits in individuals with irritable bowel syndrome, particularly when introduced abruptly.

Research citations

The sources behind this verdict.

1PubMed. Flaxseed in Diet: A Comprehensive Look at Pros and Cons, 2025. pmc.ncbi.nlm.nih.gov
2PubMed. Depletion of cyanogenic glycosides in whole flaxseed via Lactobacillaceae fermentation, 2022. pubmed.ncbi.nlm.nih.gov
3PubMed. A comprehensive review of flaxseed (Linum usitatissimum L.): health-affecting compounds, mechanism of toxicity, detoxification, anticancer and potential risk, 2022. pubmed.ncbi.nlm.nih.gov
4EFSA. Evaluation of the health risks related to the presence of cyanogenic glycosides in foods other than raw apricot kernels, 2019. efsa.europa.eu
5PubMed. Ion chromatographic determination of cyanide released from flaxseed under autohydrolysis conditions, 1995. pubmed.ncbi.nlm.nih.gov

Independently researched5 citations