Most studies of soy and
cholesterol have tested foods made from purified
soy proteins containing mainly
isoflavone glycosides. Fermented soy foods have mainly
isoflavone aglycons and account for a high proportion of the
soy protein source in Asia, where there is an inverse relationship between soy intake and serum
cholesterol. The aim of this study was to compare a novel soy germ pasta, naturally enriched in
isoflavone aglycons as a result of the manufacturing process, with conventional pasta for effects on serum
lipids and other cardiovascular risk markers. In this randomized, controlled, parallel study design of 62 adults with
hypercholesterolemia who consumed a Step II diet that included one 80-g serving/d of pasta, we measured serum
lipids,
high sensitivity C-reactive protein (
hsCRP), urinary
isoprostanes, and brachial artery flow-mediated vasodilatation at baseline and after 4 and 8 wk. The pasta delivered 33 mg of
isoflavones and negligible
soy protein and led to a serum
isoflavone concentration of 222 +/- 21 nmol/L; 69% of subjects were
equol producers. Soy germ pasta reduced serum total and
LDL cholesterol by 0.47 +/- 0.13 mmol/L (P = 0.001) and 0.36 +/- 0.10 mmol/L (P = 0.002) more than conventional pasta, representing reductions from baseline of 7.3% (P = 0.001) and 8.6% (P = 0.002), respectively. Arterial stiffness (P = 0.003) and
hsCRP (P = 0.03) decreased and improvements in all the above risk markers were greatest in
equol producers. All measures returned to baseline when patients were switched to conventional pasta. In conclusion, pasta naturally enriched with
isoflavone aglycons and lacking
soy protein had a significant hypocholesterolemic effect beyond a Step II diet and improved other cardiovascular risk markers.