PLS: Risks for human health related to the presence of plant lectins in food

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Background

  • Lectins are naturally occurring proteins found in many plants, including legumes (such as beans, lentils and peas), grains (such as wheat, barley and oats) and vegetables (such as tomatoes, potatoes and eggplants). Their main characteristic is their specific binding to carbohydrates.
  • There are different types of lectins, some binding to simple sugars (e.g. banana lectins) and others to complex carbohydrates (e.g. bean lectins). The latter can lead to adverse effects in humans, mainly gastrointestinal illnesses and allergic reactions.
  • Legumes stand out from other foods in this respect, as they contain high levels of lectins that specifically bind to carbohydrates in the cells of the gastrointestinal tract.
  • Adequate food processing and preparation (e.g. soaking and cooking) can render lectins biologically inactive (they lose the ability to bind to carbohydrates). Inadequately prepared food containing lectins can cause health problems in humans.
  • Before this scientific opinion, EFSA and other major food safety bodies had not conducted a comprehensive quantitative risk assessment of plant lectins.
  • However, the German Federal Institute for Risk Assessment (BfR) issued a statement on the health risks related to lectins in plant-based food, and several EU Member States (e.g. Germany, Ireland, Austria, Finland and Sweden) have made recommendations on safe food preparation to reduce consumer exposure to lectins.

What was EFSA asked to do?

The European Commission asked EFSA to assess the potential health risks related to the presence of plant lectins in food. This assessment focused on:

  • Lectins found in common edible plants, particularly those found in high amounts in widely consumed foods.
  • The impact of food processing (e.g., soaking and cooking) on the activity of lectins.

How did EFSA carry out this work and what data were used?

EFSA used a structured and systematic approach to assess the risk, including:

  • Extensive literature searches in scientific databases up to June 2025.
  • A systematic review and critical appraisal of relevant studies, covering data from both animals and humans and information on the mode of action.
  • Benchmark dose (BMD) modelling for toxicological effects, following EFSA’s latest guidance1.
  • Dietary exposure assessment using the EFSA Comprehensive European Food Consumption Database and the Raw Primary Food Commodity model.
  • Uncertainty analysis to quantify the impact of data gaps.

EFSA used the following data types:

  • Toxicological data: Primarily for lectins from edible plants, drawn mostly from animal studies (as there were very few human studies), where exposure to lectins was reported qualitatively.
  • Data on lectin occurrence in food: As no data were formally submitted to EFSA, the assessment relied on published research data, primarily focusing on phytohaemagglutinin (PHA), the principal lectin in beans.
  • Food consumption data: Drawn from surveys conducted in 24 EU Member States, covering data up to December 2024.

What were the outcomes and their implications?

Key outcomes:

  • Sufficient data for a risk characterisation were only available for PHA.
  • In animal studies, PHA caused adverse effects in the small intestine, pancreas and immune system. The critical effect identified was an increase in small intestine weight.
  • Some human cases of acute gastrointestinal illness have been linked to consuming undercooked beans containing active lectins. Lectins from edible plants may trigger (acute) allergic reactions in humans.
  • Adequate food processing, such as soaking and boiling beans, effectively deactivates lectins, so that they pose no health concerns in humans.
  • In an arbitrary exposure scenario, where processing only deactivates 50% of the lectins (e.g. due to insufficient cooking), the margin of exposure (MOE) falls below the safety threshold, indicating a health concern.

Implications:

  • The main risk to public health arises from inadequate preparation of lectin-containing foods, especially beans.
  • Adhering to recommended cooking practices is essential to prevent acute toxicity.

What were the limitations/uncertainties?

  • Limited toxicological data, especially for lectins other than PHA.
  • Limited human data, with most evidence coming from animal studies.
  • A lack of standardised, validated analytical methods for measuring active and inactive lectins in foods, and thus a lack of robust occurrence data.
  • Reliance on a single high-value occurrence data point for PHA in beans, extrapolated to all bean types used for the exposure estimations.

Although significant uncertainties were identified, the overall conclusion that inadequately processed beans pose a health risk is robust, with at least 95% certainty.

What are the key recommendations?

For researchers:

  • Develop and validate analytical methods to quantify both active and inactive lectins in foods.
  • Collect occurrence data for different lectins, including active and inactive forms, using appropriate and comparable analytical methods.
  • Conduct more toxicological studies, including long-term and low-dose studies in animals and humans.

For policymakers:

  • Consider establishing guidelines or regulations for the safe preparation of lectin-containing foods.
  • Promote public awareness of the importance of effective preparation practices for lectin-containing foods, especially beans.

For industry:

  • Ensure that food processing methods reliably deactivate lectins.
  • Provide clear preparation instructions on packaging for lectin-containing foods that were not processed to deactivate lectins, such as raw beans.

For all stakeholders:

  • Collect and share more occurrence data on lectins in foods, using standardised methods.
Lectins in food

Figure 1: Lectins in food and their deactivation

Glossary

Benchmark dose: The minimum dose of a substance that produces a clear, low level health risk.

Margin of exposure (MOE): A tool used in risk assessment to explore safety concerns arising from the presence of a potentially toxic substance in food or animal feed.

Toxicological effect: An adverse effect on the health, growth, behaviour or development of an organism (human, animal or plant) that results from exposure to a toxic substance.

Disclaimer

  • This plain language summary (PLS) is a simplified communication of EFSA’s Risks for human health related to the presence of plant lectins in food. The full EFSA opinion can be found here.
  • The purpose of the PLS is to enhance transparency and inform interested parties on EFSA’s work on the topic using simplified language to present a summary of the main findings.
  • The PLS was produced with the assistance of artificial intelligence, using the licensed version of Microsoft Copilot. Copilot was used to summarise EFSA's scientific output, using a standardised prompt. The generated text was reviewed by EFSA scientific staff for accuracy and completeness, and additional editing was provided by EFSA Journal staff. EFSA holds editorial responsibility for the final PLS.

Reference

1.    EFSA Scientific Committee. (2022). Guidance on the use of the benchmark dose approach in risk assessment. EFSA Journal, 20(10),7584. https://doi.org/10.2903/j.efsa.2022.7584.

Risks for human health related to the presence of plant lectins in food.

DOI: https://doi.org/10.2903/j.efsa.2026.9850

ISSN: 1831-4732

© European Food Safety Authority, 2026

Reproduction is authorised provided the source is acknowledged.