Prevention of Venous Thrombosis in Long-Haul Flights With Flite Tabs (LONFLIT-FLITE)

Long flights raise the risk of deep vein thrombosis, and this trial tested whether an oral enzyme supplement — “Flite Tabs,” containing nattokinase — could help prevent it.

In a randomized comparison of about 200 high-risk travelers on 7-to-8-hour flights, those who took the supplement had no detectable DVTs and fewer thrombotic events overall (7.4 percent versus 19.6 percent in the placebo group), along with less leg swelling. On its face, a meaningful protective signal for a cheap, accessible intervention.

The caution is in the fine print. The trial was sponsored by the product’s manufacturer, conflicts of interest were not disclosed, and the result has not been independently replicated — exactly the conditions under which a positive finding deserves skepticism until confirmed.

We rate the evidence moderate. It is a properly randomized, ultrasound-verified trial, but its manufacturer sponsorship and lack of replication keep it suggestive rather than authoritative. Travelers concerned about clot risk should weigh established measures and a clinician’s advice over a supplement resting on a single industry-funded study.