Linseed, derived from the flax plant (Linum usitatissimum) and also known as flaxseed, is valued for its nutritional content and other dietary properties. As consumption of linseed has increased, there has been a corresponding rise in reported linseed allergies, often involving severe reactions.
Several proteins in linseed, including storage proteins, oleosins, and non-specific lipid transfer proteins, have been identified as potential allergens. Despite the high cross-reactivity among seeds and tree nuts in laboratory testing conditions, clinical cross-reactivity with linseed has primarily been observed between plant proteins from the same botanical family. This includes sesame seeds, sunflower seeds, and poppy seeds. However, cases of cross-reactivity between linseed and tree nuts have been observed, despite linseed being botanically distinct from nuts.
Diagnosing linseed allergy remains challenging due to the lack of comprehensive clinical history and the absence of linseed in common multiplex immunoassays. Additionally, clinical cross-reactivity among seeds and nuts is not yet well understood, complicating food avoidance advice.
Understanding the allergenic potential of linseed is important as its use in food stuffs becomes more widespread. With more evidence, a case for labelling regulations may emerge. Until then, clear ingredient labelling and minimising risks of cross contact throughout the supply chain and manufacturing process will lead to greater consumer safety for those with linseed and cross-reactive allergies.
Reference: Mota et al. Flaxseed anaphylaxis: an emerging allergen. Porto Biomed J. 2024 Oct 25;9(5):265. doi: 10.1097/j.pbj.0000000000000265.
