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Background: Replacing animal protein with soy protein has been shown to reduce total and LDL-cholesterol concentrations in humans. However, the minimum amount of soy protein required for significant reduction of blood lipids is not known., Objective: We evaluated the amount of soy protein needed to reduce blood lipids in moderately hypercholesterolemic men., Design: Eighty-one men with moderate hypercholesterolemia (total cholesterol concentration between 5.70 and 7.70 mmol/L) were studied. After a 3-wk lead-in on a Step I diet, total cholesterol was measured and subjects were randomly divided into 5 groups. For 6 wk, each group received 50 g protein/d, which included isolated soy protein (ISP) and casein, respectively, in the following amounts: 50:0, 40:10, 30:20, 20:30, and 0:50 (control group) g. Blood was collected at baseline and weeks 3 and 6 of the intervention., Results: At week 6, significant reductions (P < 0.05) from baseline compared with the control group were found for non-HDL and total cholesterol and apolipoprotein (apo) B for all ISP groups (except total cholesterol with 40 g ISP). At week 3, significant reductions (P < 0.05) were found in apo B for the groups that consumed >/=30 g ISP and in non-HDL cholesterol for the groups that consumed >/=40 g ISP. HDL-cholesterol, apo A-I, lipoprotein(a), and triacylglycerol concentrations were not significantly affected by dietary treatment., Conclusion: Our findings show that consuming as little as 20 g soy protein/d instead of animal protein for 6 wk reduces concentrations of non-HDL cholesterol and apo B by approximately 2.6% and 2.2%, respectively. 2000;71:-84.

Soy protein, a rich source of isoflavones, fed immediately after an ovariectomy prevents bone loss in rats. Reports of the effectiveness of natural and synthetic isoflavones in preventing or treating osteoporosis led us to examine the effect of soy protein in reversing established bone loss. Seventy-two 95-d-old female Sprague-Dawley rats were assigned to 6 groups. The rats were either sham operated (SHAM; 2 groups) or ovariectomized (OVX; 4 groups) and then fed a casein-based, semipurified diet. Thirty-five days after surgery, 1 SHAM and 1 OVX group were killed to examine the occurrence of bone loss. Thereafter, the other SHAM and 1 OVX groups continued to receive the casein-based diet. Whereas the remaining 2 OVX groups received diets in which casein was replaced by soy protein with normal (OVX+SOY) or reduced (OVX+SOY-) isoflavone content for 65 days. The OVX control group had significantly lower femoral and fourth lumbar vertebral bone densities than the SHAM group. Femoral density of rats fed SOY or SOY- diets were not significantly different from SHAM or OVX controls. This suggests a slight reversal of cortical bone loss that may be partially due to higher femoral insulin-like growth factor I mRNA transcripts resulting from both the SOY and SOY- diets. The ovariectomy-induced increases in indexes of bone turnover were not ameliorated by either of the soy diets, suggesting that any positive effect of soy was achieved through enhanced bone formation rather than slowed bone resorption. Long-term consumption of soy or its isoflavones may be needed to produce small but continued increments in bone mass.

Our previous studies showed that a soy-protein diet prevents ovariectomy-induced bone loss. The purpose of this study was to determine whether isoflavones in soy protein are responsible for this bone-protective effect. Forty-eight 95-d-old Sprague-Dawley rats were divided into 4 groups: sham-operated fed a casein-based diet (SHAM), ovariectomized fed a casein-based diet (OVX+CASEIN), ovariectomized fed soy protein with normal isoflavone content (OVX+SOY), and ovariectomized fed soy protein with reduced isoflavone content (OVX+SOY-). The OVX+SOY group had significantly greater femoral bone density (in g/cm3 bone vol) than the OVX+CASEIN group, whereas OVX+SOY- was similar to OVX+CASEIN (mean +/- SD; SHAM, 1.522 +/- 0.041; OVX+CASEIN, 1.449 +/- 0.044; OVX+SOY, 1.497 +/- 0.030; OVX+SOY-, 1.452 +/- 0.030). Ovariectomy resulted in greater bone turnover as indicated by higher serum alkaline phosphatase activity, serum insulin-like growth factor I and insulin-like growth factor binding protein 3 concentrations, and urinary hydroxyproline. These increases were not affected by soy with either normal or reduced isoflavone content. Similarly, histomorphometry revealed a greater bone formation rate with ovariectomy, and this was not altered by the soy diets. The findings of this study suggest that isoflavones in soy protein are responsible for its bone-sparing effects. Further studies to evaluate the mechanism of action of isoflavones on bone are warranted.

To improve the ability to predict the occurrence of coagulation disorders in ascites retransfusion and, in addition, to better define the nature of the coagulation disorder, several proteases and antiproteases were analyzed in ascites and plasma before ascites retransfusion in 17 patients. Plasminogen, alpha 2-antiplasmin, antithrombin III, and fibrin(ogen) degradation products in ascites were significantly altered in patients who later developed abnormal coagulation as compared to those who did not. Only plasminogen and alpha 2-antiplasmin in ascites achieved a sufficient predictive value for the occurrence of coagulation abnormalities. The pattern of the coagulation abnormalities observed strongly suggests fibrinolysis induced by the infusion of plasminogen activators as the cause of the coagulation disorder in ascites retransfusion procedures.

Histological changes in the aorta were used as criteria to assess the effect of treadmill exercise on the development of atherosclerosis in rats consuming a moderately hyperlipemic diet. While grossly visible atherosclerotic plaques were absent, microscopic examination of sections of the abdominal aorta were distinctly different between exercised and sedentary rats. Aortas of sedentary rats fed a diet containing lard and cholesterol had a high degree of plaque development, fat accumulation, mineralization, erosion and necrosis. Aortas of exercised rats fed the same diet had considerably less atherogenic involvement. Both hyperlipemic groups had greater plaque formation than sedentary rats fed a normolipemic diet. In addition, there were marked differences in plasma lipids; exercise ameliorated the diet-induced changes in plasmatic atherogenic lipids. Our results indicate that exercise retards the development of atherosclerosis in rats fed a hyperlipemic diet.

The present investigation was conducted to assess the effects of exercise on diet-induced arteriosclerosis in retired breeder rats. Thirty-two 8- to 9-mo-old male Sprague-Dawley rats were allocated to one of four treatment groups: hypercholesterolemic diet-exercise (HE), hypercholesterolemic diet-sedentary (HS), normocholesterolemic diet-exercise (NE) and normocholesterolemic diet-sedentary (NS). The hypercholesterolemic diet contained 10% lard and 0.4% cholesterol. Exercise consisted of running on a motor-driven treadmill at an 8% grade 1 h per day at 0.5 mph, 6 d weekly for 5 mo. A histological assessment of the aortas demonstrated that although grossly visible atherosclerotic plaques were absent, there were significant microscopic differences among groups in the thoracic aorta, iliac bifurcation and aortic arch. Aortic histopathological changes were greatest in cross sections from rats in the HS group. The accumulation of collagen and sulfated mucosubstances was greater in the HS versus HE group. Our results demonstrate a beneficial effect of exercise on diet-induced histopathological changes in the aortas of male retired breeder rats.