Soy Impacts Lipids

Soy Impacts Lipids

HONG KONGTwo studies from theFebruary issue of The American Journal of ClinicalNutrition (www.ajcn.org) examine the impact of dietarycompounds on cholesterol levels. The first, a meta-analysis including 23randomized controlled trials, reviewed the impact of soy protein containing isoflavones on the lipid profile (81, 2:397-408, 2005). Researchers from the Chinese University of Hong Kong andPeking University, Beijing, found soy protein with intact isoflavones wasassociated with significant decreases in total cholesterol, low-densitylipoprotein (LDL) cholesterol and triacylglycerols, as well as increases in thebeneficial high-density lipoprotein (HDL). The impact was greater in men andappeared dose-dependent, with intakes over 80 mg/d with the best effects on thelipid profile. However, tablets with extracted soy isoflavones were not found toimpact cholesterol levels.

In the second study, conducted at St. Michaels Hospital, Toronto, 34 hyperlipidemic patientsunderwent three one-month treatments to determine the impact of diet oncholesterol levels (81, 2:380-87). The diets included a very-low-saturated-fatdiet (control), the control diet plus 20 mg/d lovastatin, or a portfolio dietincluding plant sterols, soy protein foods, almonds and viscous fibers fromoats, barley and psyllium. While the statin diet showed a greater impact on LDLcholesterol concentrations at four weeks (33 percent reduction) compared to theportfolio treatment (29 percent reduction), nine participants showed the bestresults on the statin diet. In addition, there was no significant differencebetween the statin and portfolio diets in ability to reduce LDL cholesterolbelow the recommended primary prevention cutoff.