Metabolic Syndrome: Soybean Foods and Serum Lipids

Metabolic syndrome is a cluster of coronary heart disease (CHD) risk factors of which central obesity, insulin resistance, increased triglycerides/decreased HDL cholesterol, and hypertension are major cardiovascular risk factors. The educational objectives of this review are to describe hypocholesteromic effects from soybean foods. Early Italian observations indicated that isolated soy protein lowered total cholesterol, especially the LDL component, in humans with elevated serum lipids. Whole soybeans, with their major phytoestrogen inflavones (genistein, daidzein, and glycetin) intact, are known to decrease both total and LDL cholesterol. Major early reviews, meta-analyses, and clinical trials in hyperlipidemic humans indicate a predictable range of decreases in serum lipids: total cholesterol (10-19%), LDL cholesterol (14-20%), and triglycerides (8-14%). Recent, large, randomized trials in postmenopausal women indicated that a soy protein component induces significant increases in HDL cholesterol. Therapy for metabolic syndrome must first be patient education, especially for predominant U.S. minority groups (Afro-, Latino-, and Native Americans). The four major preventive health educational facts necessary to reduce CHD/metabolic syndrome must now recognize that whole soybeans are abundant sources of: 1) vegetable protein, 2) high soluble fiber content, 3) virtual absence of saturated fat, though high in polyunsaturated fats, and 4) major phytoestrogens.