Effects of soy as tofu vs meat on lipoprotein concentrations

Abstract

Objectives: To investigate the effect of replacing lean meat with a soy product, tofu, on serum lipoprotein concentrations. Study and design: Randomized cross-over dietary intervention study. Subjects: Forty-two free-living healthy males aged 35 ± 62 y completed the dietary intervention. Three additional subjects were non-compliant and excluded prior to analysis. Interventions: A diet containing lean meat (150 gad) was compared with one with 290 gad tofu in an isocaloric and isoprotein substitution. Both diet periods were 1 month, and fat intake was carefully controlled. Results: Seven-day diet records showed the two diets were similar in energy, macronutrients and ®bre. Total cholesterol (mean difference 0.23 mmolal, 95% CI 0.02, 0.43; P 0.03) and triglycerides (mean difference 0.15 mmolal, 95% CI 0.02, 0.31; P 0.017) were signi®cantly lower on the tofu diet than the lean meat diet. However, HDL-C was also signi®cantly lower on the tofu diet (mean difference 0.08 mmolal, 95% CI 0.02, 0.14; P 0.01) although the LDL-C:HDL-C ratio was similar. Conclusion: The effect on HDL-C and the small LDL-C reduction differ from some other studies, where fat was often less controlled, and the comparison was of soy as textured protein or soymilk against casein. This suggests a differential effect of the various proteins compared to the soy may in¯uence the ®ndings. In practice, the replacement of meat with tofu would usually be associated with a decrease in saturated fat and an increase in polyunsaturated fat and this should enhance any small bene®ts due to the soy protein.Sponsor: Deakin University with some contribution from a Commonwealth Department of Veterans Affairs research grant.

Lupin kernel fibre-enriched foods beneficially modify serum lipids in men

“…Based on the data of Ashton and Ball (Ashton & Ball, 2000), it was predicted that a sample size of 40 subjects would be sufficient to detect a change of 5% in total serum cholesterol with a power of 80% and a ¼ 0.05. A total of 44 subjects were recruited to allow for a 10% dropout.…”

Relation between soy-associated isoflavones and LDL and HDL cholesterol concentrations in humans: a meta-analysis

“…One study (Teede et al, 2001) reports 'basic compound plus respective glycosides', which we divided by 1.666 to convert them to aglycone units. In three studies, the isoflavone form was not reported (Ashton & Ball, 2000;Vigna et al, 2000;Van Horn et al, 2001). Isoflavone contents were measured in all studies except that by Ashton and Ball (2000), who used a literature value.…”

“…In three studies, the isoflavone form was not reported (Ashton & Ball, 2000;Vigna et al, 2000;Van Horn et al, 2001). Isoflavone contents were measured in all studies except that by Ashton and Ball (2000), who used a literature value. Values for the concentrations of total, LDL and high-density lipoprotein (HDL) cholesterol in serum were divided by 1.029 to convert them to plasma values (Laboratory Methods Committee of the Lipids Research Clinics Program, 1977).…”

“…Two trials were carried out in men only (Ashton & Ball, 2000;Teixeira et al, 2000), three studies included men and women (Crouse et al, 1999;Teede et al, 2001;Jenkins et al, 2002), and five studies included women only (Baum et al, 1998;Vigna et al, 2000;Dent et al, 2001;Gardner et al, 2001;Van Horn et al, 2001). The average age of the volunteers ranged from 41 to 63 y, mean body mass index ranged from 24 to 28 kg/m 2 , and mean baseline cholesterol concentration ranged from 5.42 to 6.60 mmol/l.…”

“…Nine of the 40 were included in the analysis (Baum et al, 1998;Crouse et al, 1999;Ashton & Ball, 2000;Teixeira et al, 2000;Vigna et al, 2000;Dent et al, 2001;Gardner et al, 2001;Teede et al, 2001;Van Horn et al, 2001). We also used data from one study in press at the time we submitted our manuscript (Jenkins et al, 2002).…”