Effects of soy as tofu vs meat on lipoprotein concentrations.
OBJECTIVE
To investigate the effect of replacing lean meat with a soy product, tofu, on serum lipoprotein concentrations.


METHODS
Randomized cross-over dietary intervention study.


METHODS
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.


METHODS
A diet containing lean meat (150 g/d) was compared with one with 290 g/d 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 fibre. Total cholesterol (mean difference 0.23 mmol/l, 95% CI 0.02, 0.43; P=0.03) and triglycerides (mean difference 0.15 mmol/l, 95% CI 0.02, 0.31; P=0.017) were significantly lower on the tofu diet than the lean meat diet. However, HDL-C was also significantly lower on the tofu diet (mean difference 0.08 mmol/l, 95% CI 0.02, 0.14; P=0.01) although the LDL-C:HDL-C ratio was similar.


CONCLUSIONS
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 influence the findings. 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 benefits due to the soy protein.


BACKGROUND
Deakin University with some contribution from a Commonwealth Department of Veterans Affairs research grant. European Journal of Clinical Nutrition (2000) 54, 14-19
Ashton
E
E
School of Biological Sciences, Deakin University, Victoria, Australia.
Ball
M
M
D000328:Adult; D002784:Cholesterol / Q000097:blood; D018592:Cross-Over Studies; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage; D006801:Humans; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D008460:Meat; D008875:Middle Aged; D030262:Soybean Proteins / Q000008:administration & dosage*
D004041:Dietary Fats; D008074:Lipoproteins; D030262:Soybean Proteins; D002784:Cholesterol