NMR analysis of lipoprotein particle size does not increase sensitivity to the effect of soy protein on CVD risk when compared with the traditional lipid profile

Abstract

The traditional lipid profile compared with nuclear magnetic resonance (NMR) may underestimate the risk for cardiovascular disease and may explain some of the discrepancies in results between studies analyzing the salubrious effects of soy. Our purpose was to compare the traditional lipid profile with NMR quantification of the number of lipoprotein particles, subclasses, and diameters or sizes in 30 sedentary males, between 18 and 30 years of age, consuming 1 of the following 3 supplements daily for 28 days: milk protein (Milk), isoflavone-poor soy protein (Soy-), or isoflavone-rich soy protein (Soy+). The study used a double-blind, parallel-arm design with random assignment to 1 of the 3 protein supplement groups. Fasting EDTA blood samples were collected at baseline and after 28 days of supplementation and analyzed for the number and size of very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) particles, respectively. Fasting serum samples were analyzed for concentrations of total cholesterol (TC), LDL cholesterol (LDL-C), total HDL cholesterol (HDL-C), HDL(2)-C, HDL(3)-C, triglycerides (TGs), free fatty acids (FFAs), and glucose. Fasting heparin blood samples were collected at baseline and after supplementation and analyzed for apolipoproteins A-I, A-II, B, C-II, C-III, and E, as well as hepatic and lipoprotein lipase concentrations. HDL3-C increased by 47.2% after Soy+ supplementation and hepatic lipase decreased 19.2% after Soy- supplementation (p < 0.05). HDL-C and apolipoproteins A-I and A-II were found to increase in all 3 groups (p < 0.05). Results support that NMR analysis of lipoprotein particle number and size are not more sensitive to the effect of soy protein on CVD risk compared with the traditional lipid profile. Furthermore, the lack of isoflavones in soy protein seems to have a deleterious effect on hepatic lipase.

Scientific Opinion on the substantiation of a health claim related to isolated soy protein and reduction of blood LDL-cholesterol concentrations pursuant to Article 14 of Regulation (EC) No 1924/2006

“…In eight of the 19 RCTs, background diet was not assessed and possible confounding effects resulting from differences in background diet between the intervention and the control were not taken into account. Dietary intake was assessed in the remaining 11 studies, either by food frequency questionnaires (Allen et al, 2007;Crouse et al, 1999;Kreijkamp-Kaspers et al, 2004;Thorp et al, 2008) or by three-day dietary records (Baum et al, 1998;Greany et al, 2004;McVeigh et al, 2006;Santo et al, 2008;Steinberg et al, 2003;Teixeira et al, 2000;Van Horn et al, 2001). …”

“…Fourteen of the 19 RCTs reported no significant effect of ISP on blood LDL (Allen et al, 2007;Evans et al, 2007;Greany et al, 2004;Hoie et al, 2007;Kreijkamp-Kaspers et al, 2004;Maesta et al, 2007;McVeigh et al, 2006;Santo et al, 2008;Steinberg et al, 2003;Teede et al, 2001;Teede et al, 2005;Thorp et al, 2008;Van Horn et al, 2001) or on non-HDL (Sagara et al, 2003) cholesterol concentrations relative to controls. These studies together considered 1,520 subjects for data analysis (9-98 subjects per group/period) and provided 20 to 40 g per day of ISP for four weeks to 12 months.…”

“…One of these studies (Kreijkamp-Kaspers et al, 2004) was powered to detect a 7.4 % difference in total cholesterol concentrations between groups (β=0.2; α=0.05). Two studies were small (around 10 subjects per group) and possibly underpowered to detect moderate changes in blood cholesterol concentrations (Maesta et al, 2007;Santo et al, 2008). The Panel notes that there was a general lack of information on the statistical methodology applied in the five cross-over studies (Evans et al, 2007;Greany et al, 2004;McVeigh et al, 2006;Steinberg et al, 2003;Thorp et al, 2008), which did not allow an assessment of the appropriateness of the statistical analysis performed in each of these studies.…”

Scientific Opinion on the substantiation of a health claim related to soy protein and reduction of blood cholesterol concentrations pursuant to Article 14 of the Regulation (EC) No 1924/2006

“…On request, the applicant has identified three RCT on the effects of alcohol-washed SPI on LDL-cholesterol concentrations under the proposed conditions of use (25 g/d) (Crouse et al, 1999;Steinberg et al, 2003;Santo et al, 2008). The Panel notes that no evidence has been provided by the applicant to establish that peptides with cholesterol-lowering properties are removed from SPI by alcohol washing.…”

“…The Panel notes that no evidence has been provided by the applicant to establish that peptides with cholesterol-lowering properties are removed from SPI by alcohol washing. On request, the applicant has identified three RCT on the effects of alcohol-washed SPI on LDL-cholesterol concentrations under the proposed conditions of use (25 g/d) (Crouse et al, 1999;Steinberg et al, 2003;Santo et al, 2008).…”