Undercooked beans pose lectin health risk, warns EFSA

Undercooked beans could pose a significant public health risk, according to a new assessment from the European Food Safety Authority (EFSA), as more consumers turn to raw or minimally cooked plant-based diets.

EFSA found that exposure to lectins – naturally occurring plant proteins – can become a health concern when pulses are eaten raw or not cooked thoroughly. The European Commission commissioned the review following reports of foodborne illness linked to undercooked beans and other pulses.

Lectins are present in many legumes, grains and vegetables and help protect plants from pests. While most are harmless, some found in raw pulses can cause gastrointestinal symptoms and immune effects.

Dr. Helle Knutsen, Chair of the Panel on Contaminants in the Food Chain, said:

We developed an acute exposure scenario where beans have not been cooked enough, and half of the lectins are still present in their active form. Our assessment concludes that this scenario represents a health concern for all age groups.”

EFSA’s scientists focused on phytohemagglutinin (PHA), described as the most toxic lectin in commonly consumed edible plants. PHA is present in beans and is associated with symptoms such as nausea, vomiting, abdominal pain and diarrhoea.

Based on animal studies, EFSA identified the impact of PHA on the small intestine as the most critical health effect.

Reducing health risks

The authority stressed that properly prepared pulses are safe. Knutsen added:

Consumers can process foodstuffs to deactivate lectins. Properly soaking and boiling beans avoids potential health risks.”

To reduce lectin levels, EFSA recommends soaking pulses in water for six to 12 hours until softened, changing the water, then boiling for at least 30 minutes at 100°C. Pulses should be cooked until soft, as preparation times vary by variety.

Other household methods such as steaming, microwaving and roasting were found to be less effective at deactivating lectins.

Following EFSA’s opinion, the European Commission and Member States will consider measures to better inform and protect consumers. EFSA also highlighted data gaps and called for further studies into lectin levels in raw and processed foods and their effects on humans and animals