A MARKED AND SUSTAINED REDUCTION IN LDL STEROLS BY DIET AND CHOLESTYRAMINE IN BETA-SITOSTEROLEMIA

This study examines the therapeutic outcome of a low plant sterol diet and adjunctive drug therapy (cholestyramine) in the long term treatme nt of beta-sitosterolemia. A diet restricted in plant sterols, cholest erol and fat was implemented in a 48-year-old male beta-sitosterolemic patient. The plant sterols beta-sitosterol, campesterol and stigmaste rol, and cholesterol content of the diet were quantitated by a gas chr omatography method (GLC) during metabolic ward studies. Food table ana lysis of dietary sterols, while quantitatively similar to GLC, signifi cantly underestimated the level of plant sterols and therefore overest imated dietary cholesterol intake. The duration of the study was 18 mo nths. The effect of the diet over a period of 6 months on the sterol l evels of plasma and individual lipoprotein fractions (VLDL, LDL, HDL) was evaluated. Apolipoproteins A-1 and B-100 levels were measured. The same parameters were assessed over the next 12 months with the adjunc tive use of cholestyramine and dietary restrictions. The diet was effe ctive in lowering total, VLDL, and LDL plant sterols by 37%, 59%, and 32% respectively. The low plant sterol diet did not change total plasm a, VLDL or LDL cholesterol. With the addition of cholestyramine, total plasma and LDL cholesterol declined by 64 and 76%, respectively, whil e HDL-cholesterol remained unchanged. LDL plant sterols declined by 77 %, while VLDL plant sterol showed no further change. The decline showe d no discrimination among the individual plant sterols. One week after cholestyramine therapy, apolipoprotein B fell from 1.03 to 0.11 g/L, while apolipoprotein A rose from 1.29 to 1.79 g/L. These levels subseq uently stabilized at 70% below (0.29 g/L) and 42% above (1.81 g/L) tha t of diet therapy alone. Xanthomas, angina pectoris, and intermittent claudication resolved during the diet and cholestyramine therapy perio d. Dietary restriction of plant sterols combined with cholestyramine t herapy is an effective means of treating beta-sitosterolemia.