The margarines were produced by Unilever R&D every six months and stored at -20˚C. Upon inclusion in the study, the patients received six tubs of trial margarine to bridge the gap until the first delivery. Thereafter the patients received eight tubs of margarine every 12 weeks by cooled courier transport (Valid Express, Amsterdam), under supervision of a specialized logistics company (L.O.F. bv, Egmond aan den Hoef). Any remaining tubs were returned by the subjects to the same logistical company when the next delivery came. The number of returned tubs was registered to calculate actual margarine intake at the end of the study.