Double-blind study of the addition of high-protein soya milk v. cows' milk to the diet of patients with severe hypercholesterolaemia and resistance to or intolerance of statins

Total substitution of soyabean protein for animal protein in the diet has been repeatedly shown to lower plasma cholesterol levels in hypercholesterolaemic individuals. A new, highly palatable, high-protein soya drink may allow replacement of a significant percentage of animal protein in the diet. The soya drink was given, within a crossover design v. a cows' milk preparation of similar composition and taste, to twenty-one severely hypercholesterolaemic patients (mean baseline plasma cholesterol 8.74 mmol/l) with a history of resistance to or intolerance of statin treatment. Each dietary supplement was given for 4 weeks, with a 4-week interval between treatments, Plasma lipid levels were monitored every 2 weeks during each dietary sequence. The concomitant dietary treatment, which had been followed for a long time by all patients, was carefully monitored throughout the study. The soya supplementation reduced plasma rotal cholesterol level by 6.5 %, when given first, and by 7.4 % when given after cows' mill; When given first, cows' milk resulted in a small, non-significant reduction of plasma cholesterol level (-3.9 %), and when given after soya, it changed total plasma cholesterol to a minimal extent (-1.6 %). Changes in total and LDL-cholesterol levels after 2 and 4 weeks of soya v. cows' milk treatment were, thus, respectively -6.1, -7.0 and -6.2, -7.8 % (both P < 0.05). These first data from a double-blind study confirm a significant cholesterol-lowering effect of soyabean protein, even when only partly replacing animal protein in the diet, in individuals with extreme-plasma cholesterol elevations.