Soy Milk with a High Glycitein Content Does Not Reduce Low-Density Lipoprotein Cholesterolemia in Type II Hypercholesterolemic Patients

In order to evaluate acceptability and effectiveness of a partial addition of soy protein to the daily diet in well-established type II hypercholesterolemic individuals, a double-blind study was carried out with a soy milk providing 25 g/day of protein versus an identically formulated cow’s milk. Twenty patients with type II hypercholesterolemia, 4 males and 16 females, age range 38–76 years, all with cholesterol levels >7 mmol/l and low-density lipoprotein cholesterol <5.5 mmol/l, were selected. Significant triglyceride elevations (WHO Fredrickson type IIB) were present in 4 patients, and the body mass index was 24.2 ± 3.47 kg/m². Different from prior studies, either with isoflavone-free products or with a moderately isoflavone-rich milk, the milk in the present study did not reduce total and low-density lipoprotein cholesterolemia. A detailed analysis of the composition showed significant differences in the isoflavone content versus products used in prior studies with a positive outcome. Soy milk isoflavones were, in fact, characterized by a high glycitein content and a low genistein/daidzein ratio. Glycitein is a minor component in most soy products, and its role in cholesterol regulation is unclear. In view of the high interest in the use of soy products for the prevention of coronary diseases, the metabolic behavior of different isoflavones in man should be better characterized, and the role of isoflavone composition of soy products given for the control of cholesterolemia needs further clarification.