Japan Bio Science Laboratory (JBSL) says its ingredient has an “anti-blood-clotting effect, controls blood pressure, and lowers blood viscosity to improve circulation, making it an effective supplement to combat heart disease”.
Yet following a positive opinion on the novel food from the Belgian authority, member states expressed concern about the ingredient's long-term impact on blood clotting.
One case report showed a patient on anti-hypertensive agents and low-dose aspirin for secondary stroke prevention experienced an "acute cerebellar haemorrhage and cerebral microbleeds" after taking nattokinase alongside the medicines.
The dossier was forwarded onto EFSA by the European Commission to address the concerns, which also included potential allergenicity and substantiation of whether the ingredient was absorbed into the blood stream when consumed orally.
Yet EFSA said in its final opinion the fermented soybean extract NSK-SD – which contains the traditional Japanese ingredient nattokinase – was safe under the conditions put forward by the Osaka-headquartered company.
The company proposed a daily maximum intake of 100 mg of NSK-SD as a food supplement among the target population of healthy over 35s, excluding pregnant and lactating women.
“Taking into account the no observed adverse effect level (NOAEL) of 1,000 mg/kg body weight per day in the subchronic toxicity study in rats, and considering the proposed maximum intake level for the novel food, the Panel concludes that the margin of exposure is sufficient,” wrote EFSA's Dietetic Products, Nutrition and Allergies (NDA) panel.
NSK-SD contains nattokinase, which is a serine protease composed of 275 amino acid residues.
Nattokinase was originally isolated from the traditional Japanese breakfast food 'natto' - soybeans fermented with Bacillus subtilis var. natto.
The ingredient is already sold in the US and 11 other countries.