Blood lipid and oxidative stress responses to soy protein with isoflavones and phytic acid in postmenopausal women

The Antioxidant Role of Soy and Soy Foods in Human Health

Oxidative stress seems to play a role in many chronic diseases, such as cardiovascular diseases, diabetes, and some cancers. Research is always looking for effective approaches in the prevention and treatment of these pathologies with safe strategies. Given the central role of nutrition, the identification of beneficial healthy foods can be the best key to having a safe and at the same time effective approach. Soy has always aroused great scientific interest but often this attention is galvanized by the interaction with estrogen receptors and related consequences on health. However, soy, soy foods, and soy bioactive substances seem to have antioxidant properties, suggesting their role in quenching reactive oxygen species, although it was frequently mentioned but not studied in depth. The purpose of this review is to summarize the scientific evidence of the antioxidant properties of soy by identifying the human clinical trials available in the literature. A total of 58 manuscripts were individuated through the literature search for the final synthesis. Soy bioactive substances involved in redox processes appear to be multiple and their use seems promising. Other larger clinical trials with adequate standardization and adequate choice of biomarkers will fill the gap currently existing on the suggestive role of soy in antioxidant mechanisms.

The Role of Meat Protein in Generation of Oxidative Stress and Pathophysiology of Metabolic Syndromes

Various processing methods have a great impact on the physiochemical and nutritional properties of meat that are of health concern. Hence, the postmortem processing of meat by different methods is likely to intensify the potential effects on protein oxidation. The influence of meat protein oxidation on the modulation of the systemic redox status and underlying mechanism is well known. However, the effects of processed meat proteins isolated from different sources on gut microbiota, oxidative stress biomarkers, and metabolomic markers associated with metabolic syndromes are of growing interest. The application of advanced methodological approaches based on OMICS, and mass spectrometric technologies has enabled to better understand the molecular basis of the effect of processed meat oxidation on human health and the aging process. Animal studies indicate the involvement of dietary proteins isolated from different sources on health disorders, which emphasizes the impact of processed meat protein on the richness of bacterial taxa such as (Mucispirillum, Oscillibacter), accompanied by increased expression of lipogenic genes. This review explores the most recent evidences on meat processing techniques, meat protein oxidation, underlying mechanisms, and their potential effects on nutritional value, gut microbiota composition and possible implications on human health.

The effects of soy on scopolamine-induced spatial learning and memory impairments are comparable to the effects of estradiol

Background Modulatory effects of soy extract and estradiol on the central nervous system (CNS) have been reported. The effect of soy on scopolamine-induced spatial learning and memory in comparison to the effect of estradiol was investigated. Materials and methods Ovariectomized rats were divided into the following groups: (1) control, (2) scopolamine (Sco), (3) scopolamine-soy 20 (Sco-S 20), (4) scopolamine-soy 60 (Sco-S 60), (5) scopolamine-estradiol 20 (Sco-E 20) and (6) scopolamine-estradiol 60 (Sco-E 60). Soy extract, estradiol and vehicle were administered daily for 6 weeks before training in the Morris water maze (MWM) test. Scopolamine (2 mg/kg) was injected 30 min before training in the MWM test. Results In the MWM, the escape latency and traveled path to find the platform in the Sco group was prolonged compared to the control group (p < 0.001). Treatment by higher doses of soy improved performances of the rats in the MWM (p < 0.05 - p < 0.001). However, treatment with both doses of estradiol (20 and 60 μg/kg) resulted in a statistically significant improvement in the MWM (p < 0.01 - p < 0.001). Cortical, hippocampal and serum levels of malondialdehyde (MDA), as an index of lipid peroxidation, were increased which was prevented by soy extract and estradiol (p < 0.001). Cortical, hippocampal as well as serum levels of the total thiol, superoxide dismutase (SOD) and catalase (CAT) in Sco group were lower than the control group (p < 0.001) while they were enhanced when the animals were treated by soy extract and estradiol (p < 0.01 - p < 0.001). Conclusions It was observed that both soy extract and estradiol prevented learning and memory impairments induced by scopolamine in ovariectomized rats. These effects can be attributed to their protective effects on oxidative damage of the brain tissue.

Processed Meat Protein Promoted Inflammation and Hepatic Lipogenesis by Upregulating Nrf2/Keap1 Signaling Pathway in Glrx-Deficient Mice

Oxidative stress may play a critical role in the progression of liver disorders. Increasing interest has been given to the associations among diet, oxidative stress, gut-liver axis, and nonalcoholic fatty liver disease. Here, we investigated the effects of processed meat proteins on biomarkers of lipid homeostasis, hepatic metabolism, antioxidant functions, and gut microbiota composition in glutaredoxin1 deficient (Glrx1^-/-) mice. The wild-type (WT) and Glrx1^-/- mice were fed a soy protein diet (SPD), a dry-cured pork protein diet (DPD), a braised pork protein diet (BPD), and a cooked pork protein diet (CPD) at a dose of 20% of protein for 3 months. Serum and hepatic total cholesterol, serum endotoxin, hepatic liver droplet %, and antioxidant capacity were significantly increased in the CPD fed WT mice. In addition, CPD fed Glrx1^-/- mice significantly increased total cholesterol, triacylglycerol, and pro-inflammatory cytokines which are accompanied by higher steatosis scores, intrahepatic lipid accumulation, and altered gene expression associated with lipid metabolism. Furthermore, hepatic gene expression of Nrf2/keap1 signaling pathway and its downstream signaling targets were determined using RT-qPCR. Glrx1 deficiency increased Nrf2 activity and expression of its target genes (GPx, catalase, SOD1, G6pd, and Bbc3), which was exacerbated by intake of CPD. Metagenomic analyses revealed that Glrx1^-/- mice fed meat protein diets had higher abundances of Mucispirillum, Oscillibacter, and Mollicutes but lower abundances of Bacteroidales S24-7 group_norank, Blautia, and Anaerotruncus than their wild-type counterparts. In summary, Glrx1 deficiency induced an increase in serum biomarkers for lipid homeostasis, gut microbiota imbalance, and upregulation of Nrf2/Keap1 and antioxidant defense genes, which was aggravated by cooked meat protein diet.

Clinical and metabolic response to soy administration in older women with metabolic syndrome: a randomized controlled trial

BACKGROUND

There are many studies on the health effects of soy, only a few describe the effects of the simultaneous use of two types of soy on multiple components of metabolic syndrome (MetS). The present study was designed to determine the effects of roasted soy-nut and textured soy protein (TSP) intake on clinical and metabolic status of older women with MetS borderline parameters.

METHOD

This randomized, single-blind, controlled clinical trial included 75 women ≥ 60 years old with a diagnosis of MetS based on ATP III criteria. The participants were randomly allocated into three groups of 25 people; soy-nut, TSP and control groups for 12 week. Fasting blood samples were taken at the beginning and end of the trial to compare the metabolic responses. All participants provided three dietary records and physical activity records during the intervention. We used the Kolmogorov-Smirnov, ANOVA, ANCOVA, paired-t test, and the Generalized Linear Model (GLM) repeated measures analysis.

RESULTS

Dietary intake and physical activity of the participants in two groups were not significantly different. After 12 weeks of intervention the participants who received soy-nut had a significant decrease in total cholesterol (TC) (p < 0.001), low density lipoprotein, very low density lipoprotein, apolipoprotein B100, fasting blood glucose, insulin (p < 0.05), HOMA-IR, malondialdehyde (MDA) (p < 0.01) level. Morever, a significant increase in total antioxidant capacity (TAC) (p < 0.01) level compared with the control group. At the same time, the TSP brought significant decrease only in TC, insulin, MDA (p < 0.05) level and a significant increase in total TAC (p < 0.05) level. We did not find any significant effect in intervention groups, on apolipoprotein AI, triglyceride (TG), high density lipoprotein (HDL-C), TG/HDL, C-reactive protein and fibrinogen levels after intervention.

CONCLUSION

Short-term intakes of roasted soy-nut and TSP have shown to improve the lipid profiles, markers of glucose intolerance and oxidative stress; although the roasted soy-nut was more effective than TSP. Therefore, a moderate daily intake of roasted soy-nut as snacks or TSP as a meal complement by individuals with borderline parameters of MetS can be a safe and a practical modality to avoid the progression of the disease as well as to limit the side effects of drug intake.Trial registration MUBABOL.REC.1388.1.

Isoflavone supplementation plus combined aerobic and resistance exercise do not change phase angle values in postmenopausal women: A randomized placebo-controlled clinical trial

OBJECTIVE

The aim of this study was to evaluate the effect of isoflavone supplementation plus combined exercise protocol on phase angle (PhA) values in postmenopausal women.

METHODS

Thirty postmenopausal women were randomly assigned in a double blind, placebo-controlled clinical trial divided into two groups: 100 mg/day of isoflavone supplementation (n = 16) and 100 mg/day of starch (placebo; n = 14). In addition, both groups performed a combined aerobic and resistance exercise during 10 weeks. Body composition and PhA were evaluated by bioelectrical impedance.

RESULTS

PhA values did not change in the isoflavone group (PRE: 6.7 ± 0.7° to POST: 6.7 ± 0.6°) and in the placebo group (PRE: 7.2 ± 1.0° to POST: 6.8 ± 0.5°); p group = 0.304, p time = 0.227, p group x time interaction = 0.137. Additionally, delta values were not different (0.04 ± 0.5° vs. -0.40 ± 0.99°; p = 0.176) between isoflavone and placebo groups, respectively.

CONCLUSION

We conclude that isoflavone supplementation plus combined aerobic and resistance exercise did not change PhA in postmenopausal women. The patients were part of ClinicalTrials.gov: NCT03008785.

Low-density lipoprotein oxidation biomarkers in human health and disease and effects of bioactive compounds

Based on the significance of oxidized low-density lipoprotein (LDL) in health and disease, this review focuses on human studies addressing oxidation of LDL, including three lines of biomarkers, (i) ex vivo LDL resistance to oxidation, a "challenge test" model, (ii) circulating oxidized LDL, indicating the "current in vivo status", and (iii) autoantibodies against oxidized LDL as fingerprints of an immune response to oxidized LDL, along with circulating oxysterols and 4-hydroxynonenal as biomarkers of lipid peroxidation. Lipid peroxidation and oxidized LDL are hallmarks in the development of various metabolic, cardiovascular and other diseases. Changes further occur across life stages from infancy to older age as well as in athletes and smokers. Given their responsiveness to targeted nutritional interventions, markers of LDL oxidation have been employed in a rapidly growing number of human studies for more than 2 decades. There is growing interest in foods, which, besides providing energy and nutrients, exert beneficial effects on human health, such as protection of DNA, proteins and lipids from oxidative damage. Any health claim, however, needs to be substantiated by supportive evidence derived from human studies, using reliable biomarkers to demonstrate such beneficial effects. A large body of evidence has accumulated, demonstrating protection of LDL from oxidation by bioactive food compounds, including vitamins, other micronutrients and secondary plant ingredients, which will facilitate the selection of oxidation biomarkers for future human intervention studies and health claim support.

Soya products and serum lipids: a meta-analysis of randomised controlled trials

Soya proteins and isoflavones have been reported to exert beneficial effects on the serum lipid profile. More recently, this claim is being challenged. The objective of this study was to comprehensively examine the effects of soya consumption on the lipid profile using published trials. A detailed literature search was conducted via MEDLINE (from 2004 through February 2014), CENTRAL (The Cochrane Controlled Clinical Trials Register) and ClinicalTrials.gov for randomised controlled trials assessing the effects of soya on the lipid profile. The primary effect measure was the difference in means of the final measurements between the intervention and control groups. In all, thirty-five studies (fifty comparisons) were included in our analyses. Treatment duration ranged from 4 weeks to 1 year. Intake of soya products resulted in a significant reduction in serum LDL-cholesterol concentration, -4.83 (95% CI -7.34, -2.31) mg/dl, TAG, -4.92 (95% CI -7.79, -2.04) mg/dl, and total cholesterol (TC) concentrations, -5.33 (95% CI -8.35, -2.30) mg/dl. There was also a significant increase in serum HDL-cholesterol concentration, 1.40 (95% CI 0.58, 2.23) mg/dl. The I² statistic ranged from 92 to 99%, indicating significant heterogeneity. LDL reductions were more marked in hypercholesterolaemic patients, -7.47 (95% CI -11.79, -3.16) mg/dl, than in healthy subjects, -2.96 (95% CI -5.28, -0.65) mg/dl. LDL reduction was stronger when whole soya products (soya milk, soyabeans and nuts) were used as the test regimen, -11.06 (95% CI -15.74, -6.37) mg/dl, as opposed to when 'processed' soya extracts, -3.17 (95% CI -5.75, -0.58) mg/dl, were used. These data are consistent with the beneficial effects of soya proteins on serum LDL, HDL, TAG and TC concentrations. The effect was stronger in hypercholesterolaemic subjects. Whole soya foods appeared to be more beneficial than soya supplementation, whereas isoflavone supplementation had no effects on the lipid profile.

The short-term effects of soybean intake on oxidative and carbonyl stress in men and women

Beyond other beneficial effects, a soy-rich diet has been shown to reduce the risk of cardiovascular diseases and diabetic complications. Reduction of oxidative and carbonyl stress has been proposed as the underlying mechanism, but the evidence for this is lacking. The aim of our study was to evaluate the effects of short-term increased soy intake on oxidative and carbonyl stress parameters in young volunteers. Young healthy probands (omnivores) of both genders (55 women, 33 men) were given soybeans (2 g/kg bodyweight daily) for one week. Markers of oxidative and carbonyl stress were measured in plasma at the beginning and at the end of one week soybean intake and after another week of a wash-out period. Total antioxidant capacity was increased by soybean intake in both genders. This led to decreased levels of advanced oxidation protein products in women, but not in men. On the contrary, in men, soybean intake increased lipoperoxidation. No effects on carbonyl stress markers (advanced glycation end products-specific fluorescence and fructosamine) were found. Soybean intake has gender-specific effects on oxidative stress in young healthy probands potentially due to divergent action and metabolism of phytoestrogens in men and women. Effects of soybean intake on carbonyl stress should be evaluated in longer studies.

Antioxidant characterization of soy derived products in vitro and the effect of a soy diet on peripheral markers of oxidative stress in a heart disease model

This study analyzed and compared the content of isoflavones in 2 soy products, the effectiveness of isoflavones as antioxidants, in vitro, and demonstrated the antioxidant effect of a soy diet in rats with myocardial infarction (MI). Isoflavone content was analyzed in soybean hypocotyl (SH) and isolated soy protein (ISP). The quality (TAR) and quantity (TRAP) of antioxidants present in the samples was quantified. The amount of daidzin was higher in SH (9 times) and genistein in ISP (5 times). SH presented a 3-fold increase in TAR, while both products exhibited same TRAP. The rats were fed an ISP diet for 9 weeks. Animals were distributed among 6 treatment groups: (i) Sham Casein; (ii) Infarct Casein < 25%; (iii) Infarct Casein > 25%; (iv) Sham Soy; (v) Infarct Soy < 25%; and (vi) Infarct Soy > 25%. MI was induced 5 weeks after the commencement of the diets. Lipid peroxidation (LPO), antioxidant enzyme activity, and levels of nitrites/nitrates were determined in blood. Rats receiving the ISP diet demonstrated increased activity of antioxidant enzyme activity and nitrite/nitrate content. In addition, the increase in LPO seen in rats subjected to MI was significantly mitigated when the ISP diet was given. These findings suggest a nutritional approach of using a soy-based diet for the prevention of oxidative-stress-related diseases such as heart failure.

[Evaluation of the intake of a low daily amount of soybeans in oxidative stress, lipid and inflammatory profile, and insulin resistance in patients with metabolic syndrome]

OBJECTIVE

Studies show that regular consumption of soybeans reduces the risk of diabetes and cardiovascular diseases. However, most of these studies recommend daily intake of 25 g or more of soy protein, an amount considered high and not well tolerated by patients. The objective of this study was to assess the effect of low daily intake of soybeans in oxidative stress and in components of the metabolic syndrome (MS).

SUBJECTS AND METHODS

Forty individuals with MS were selected and divided into two groups: control group (n = 20) and soybean-treated group (n = 20), which consumed 12.95 g of soy protein for 90 days.

RESULTS

After the treatment, the soybean-treated group showed a decrease in fasting glucose and increase in serum HDL and adiponectin.

CONCLUSION

Low intake of soy protein for 90 days, besides being well tolerated by the patients, was able to improve several parameters related to the pathophysiology of MS.

Effect of free or protein-associated soy isoflavones on the antioxidant status in rats

BACKGROUND

The objective of this study was to investigate the effect of chronic ingestion of free and protein-associated soy isoflavones on the antioxidant status in male Wistar rats. Free isoflavone (iso), protein-associated soy isoflavone (iso + prot) and soy protein (prot) extracts were administered for 30 days by gavage to the rats at a dosage of 1 mg aglycone isoflavones per 200 g body weight, adjusted daily, and the prot group was given the same concentration of soy protein received by the iso + prot group. Antioxidant capacity of plasma, thiobarbituric acid-reactive substance (TBARS) and glutathione (GSH) levels and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma, erythrocytes and tissues and gene expression levels in liver and kidney were evaluated.

RESULTS

Chronic ingestion of free but not of protein-associated soy isoflavones nor of solely soy protein increased plasma antioxidant capacity and GPx activity in erythrocytes. Soy protein increased CAT activity and gene expression in liver. SOD activity in erythrocytes was increased by all treatments.

CONCLUSION

The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism.

Fermented soymilk increases voluntary wheel running activity and sexual behavior in male rats

Wheel running by rodents is thought to reflect voluntary exercise in humans. The present study examined the effect of fermented soymilk (FSM) on voluntary wheel running in rats. FSM was prepared from soymilk (SM) using the bacteria Leuconostoc pseudomesenteroides . The rats were fed a normal diet for 3 weeks followed by a 3-week administration of diet containing FSM or SM (5% w/w), and then the diets were switched back to a normal diet for 3 weeks. The voluntary wheel running activity was increased by FSM administration, although no changes were observed by SM administration. This effect was observed 2 weeks after FSM administration and lasted 1 week after deprivation of FSM. Then we evaluated the effect of FSM on sexual behavior in male rats. FSM administration for 10 days significantly increased the number of mounts. The protein expression of tyrosine hydroxylase (TH) increased in the hippocampus by FSM administration and it is suggested that FSM may change norepinephrine or dopamine signaling in the brain. Our study provides the first evidence that FSM increases voluntary wheel running activity and sexual behavior and suggests that TH may be involved in these effects.

One-year soy protein supplementation does not improve lipid profile in postmenopausal women

OBJECTIVE

The risk of heart disease increases significantly in women after menopause mostly because of estrogen deficiency. Soy protein, a good source of isoflavones that are known to bind estrogen receptors, has also been promoted as a dietary means for reducing the risk of heart disease. The aim of this study was to examine the effects of soy protein consumption on heart disease risk in postmenopausal women.

METHODS

Moderately hypercholesterolemic postmenopausal women were randomly assigned to consume soy or control foods daily for 1 year. Serum samples were analyzed for total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein (Apo) A, and Apo B. Sixty-two women completed the study.

RESULTS

There was a trend for total cholesterol and high-density lipoprotein cholesterol levels to increase after 1 year of soy protein supplementation (230.04 +/- 6.1 vs 242.57 +/- 6.2 mg/dL, P < 0.1, and 56.87 +/- 2.5 vs 60.33 +/- 2.5 mg/dL, P < 0.1, respectively). There were no significant differences in low-density lipoprotein cholesterol or triglyceride levels; however, a significant increase in Apo B levels (105.5 +/- 5.9 vs 120.21 +/- 5.9 mg/dL; P = 0.002) and a significant decrease in Apo A levels (189.36 +/- 10 vs 173.21 +/- 10 mg/dL; P = 0.009) were seen.

CONCLUSIONS

Our data indicate that 1-year soy protein supplementation did not confer cardiovascular benefits, in terms of favorable alterations in the lipid profile, in this cohort of postmenopausal women. These findings, as well as those from other studies, lend credence to the decision of the Food and Drug Administration to reevaluate the soy protein health claim issued a decade ago.

Effect of dietary sodium phytate and microbial phytase on the lipase activity and lipid metabolism of broiler chickens

The objective of the present study was to investigate the effect of dietary phytate and microbial phytase on the lipase activity, lipid metabolism and mRNA expressions of fatty acid synthase (FASN) and leptin in broiler chickens. The study was conducted as a 2 x 3 factorial arrangement of treatments with phytate phosphorus at 0.20 and 0.40 % (added as the sodium phytate) and supplemental microbial phytase at 0, 500, or 1000 phytase units/kg. The results showed that phytase improved (P < 0.05) the growth performance and ileal digestibility of nutrients of broilers, but phytate had no effect (P>0.05) on these parameters, except the decrease (P < 0.01) in the digestibility of Ca. Phytate decreased (P < 0.05) the lipase activity, serum total cholesterol (T-CHO) and hepatic TAG, and elevated (P < 0.01) serum NEFA and HDL cholesterol. Phytase decreased (P < 0.05) serum NEFA, but increased (P < 0.01) serum T-CHO and hepatic TAG. Phytate and phytase also influenced (P < 0.01) the mRNA expressions of leptin in the liver. There were significant (P < 0.05) interactions of phytate and phytase on the concentrations of serum TAG and LDL cholesterol, hepatic NEFA and T-CHO, and the mRNA expressions of FASN. The results suggest that phytate and phytase can affect lipase activity and lipid metabolism of broiler chickens.

Effect of dietary phytate and phytase on metabolic change of blood and intestinal mucosa in chickens

The objective of this study was to investigate the effect of dietary phytate and phytase on the metabolic parameters of lipid, protein, enzyme, electrolyte in the blood or intestinal mucosa of broiler chickens. Diets containing phytate phosphorus (0.22% or 0.44%) with phytase supplementation (0, 500 or 1000 U/kg) were administrated to 504 Cobb chicks for 4 weeks. Results showed that the serum concentrations of total cholesterol (T-CHO), albumin, albumin/globulin, total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and glutamic pyruvic transaminase (GPT) were decreased by 9-41% in high phytate diets (p < 0.05) and the concentrations of blood P, K, Fe, Cu, Zn and Mg were decreased by 4-14% for birds fed high phytate diets (p < 0.05), whereas inclusion of phytase compensated these adverse influences. In the duodenum, phytate decreased the level of T-AOC by 13% (p < 0.05), whereas phytase increased the levels of T-SOD, T-AOC and alkaline phosphatase (ALP) by 9-16% (p < 0.05). Also, in the jejunum, diets with high phytate showed lower activity of T-SOD, T-AOC and glutamic oxaloacetic transaminase (GOT) (p < 0.05), and phytase increased T-SOD, T-AOC and ALP (p < 0.05). However, phytase decreased transaminase activity in the low phytate basal diets (p < 0.05). This study suggests that dietary phytate can adversely interfere with the metabolisms of lipid and protein, as well as the antioxidation of blood and intestinal cells, while phytase supplementation may compensate these effects for broiler chickens.

Effects of Soy Consumption on Serum Lipids and Apoproteins in Peritoneal Dialysis Patients: A Randomized Controlled Trial

Background

Lipid abnormalities, particularly high serum concentration of lipoprotein(a) [Lp(a)], are one of the major risk factors for cardiovascular disease (CVD) in peritoneal dialysis (PD) patients. The present study was designed to investigate the effects of soy consumption on serum lipids and apoproteins, especially Lp(a), in PD patients.

Methods

This study was a randomized clinical trial in which 40 PD patients (20 males, 20 females) were randomly assigned to either the soy or the control group. Patients in the soy group received 28 g/day textured soy flour (containing 14 g of soy protein) for 8 weeks, whereas patients in the control group received their usual diet, without any soy. At baseline and the end of week 8 of the study, 5 mL of blood was collected from each patient after a 12- to 14-hour fast and serum triglyceride, total cholesterol, low density lipoprotein-cholesterol (LDL-C), high density lipoprote-incholesterol (HDL-C), apoprotein B100 (apo B100), apoprotein AI (apo AI), and Lp(a) were measured.

Results

In the present study, serum Lp(a) concentrations were above the normal range in 86% of the PD patients. Mean serum Lp(a) concentration was reduced significantly, by 41%, in the soy group at the end of week 8 compared to baseline ( p < 0.01); the reduction was also significant compared to the control group ( p < 0.05). During the study, mean serum Lp(a) concentration did not change significantly in the control group. There were no significant differences between the two groups in mean changes in serum triglyceride, total cholesterol, HDL-C, LDL-C, apo B100, or apoAI.

Conclusion

The results of our study indicate that soy consumption reduces serum Lp(a) concentration, which is a risk factor for cardiovascular disease in peritoneal dialysis patients.

Soy constituents: modes of action in low-density lipoprotein management

Reviewed here are the modes of action of soy components used as ingredients in foods, which can lower plasma levels of low-density lipoprotein (LDL) and cholesterol, which are markers for the risk for atherosclerosis. Soy ingredients act via more than one mode of action including the following: LDL absorption suppression, cholesterol efflux stimulation, LDL resorption stimulation, LDL oxidation prevention, LDL particle size increase, cholesterol synthesis reduction, and bile secretion increase. Individual genetics, lifestyle, and nutrition habits alter LDL management and a better understanding of the various modes of actions of soy ingredients may facilitate the composition of effective ingredient cocktails. The optimization of food components offers further alternatives to LDL management to augment drug therapy for patients who are unable to reach their target LDL cholesterol levels or who are suffering from side effects or drug insensitivity.

Effects of soy consumption on oxidative stress, blood homocysteine, coagulation factors, and phosphorus in peritoneal dialysis patients

OBJECTIVE

We studied the effects of soy consumption on oxidative stress, blood homocysteine, coagulation factors, and phosphorus in peritoneal dialysis patients.

DESIGN

This was an unblinded, randomized clinical trial.

SETTING

This study involved peritoneal dialysis centers in Tehran, Iran.

PATIENTS

We included 40 peritoneal dialysis patients (20 males and 20 females).

INTERVENTION

Peritoneal dialysis patients were randomly assigned to either a soy or control group. Patients in the soy group received 28 g/day textured soy flour (containing 14 g of soy protein) for 8 weeks, whereas patients in the control group received their usual diet, without any soy.

MAIN OUTCOME MEASURES

Blood oxidized low-density lipoprotein (ox-LDL), homocysteine, phosphorus, fibrinogen concentrations, and the activities of coagulation factors VII, IX, and X were measured at baseline and at the end of week 8 of the study.

RESULTS

The percentage of plasma coagulation factor IX activity decreased significantly by 17% in the soy group at the end of week 8 compared with baseline (P < .01), and the reduction was significant compared with the control group (P < .05). There were no significant differences between the two groups in mean changes of blood ox-LDL, homocysteine, phosphorus, fibrinogen concentrations, and the activities of coagulation factors VII and X.

CONCLUSION

Soy consumption reduces plasma coagulation factor IX activity, which is a risk factor for thrombosis in peritoneal dialysis patients.

Diet with isolated soy protein reduces oxidative stress and preserves ventricular function in rats with myocardial infarction

We investigated the effects of an isolated soy protein (ISP) diet offered over a 9-week period to rats in whom myocardial infarction (MI) had been induced, and a casein diet given as a control. Male Wistar rats were assigned to six groups after infarct size determination (n=8/group): Sham Casein (SC); Infarct Casein <25% (IC<25%); Infarct Casein >25% (IC>25%); Sham Soy (SS); Infarct Soy <25% (IS<25%); and Infarct Soy >25% (IS>25%). MI surgery was performed at the fifth week, and one month later, the animals were hemodynamically assessed to evaluate left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), contractility and relaxation indexes (+/-dP/dt). Lung and liver specimens were also collected for the estimation of organ congestion. Oxidative stress was evaluated in heart homogenates through chemiluminescence (CL), carbonyl groups, and antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Infarcted groups treated with casein showed cardiac hypertrophy, lung and liver congestion, increased LVEDP and decreased LVSP and +/-dP/dt, all typical signals of heart failure. Ventricular dysfunction was correlated with increased myocardial oxidative damage as seen by CL and carbonyl groups data in the groups IC<25% and IC>25% (3 and 10-fold increase, respectively). The ISP diet was able to improve ventricular systolic and diastolic function in the groups IS<25% and IS>25% (LVEDP was reduced by 44% and 24%, respectively) and to decrease myocardial oxidative stress. The overall results confirm the preventive role of soy-derived products in terms of post-MI myocardial dysfunction probably by an antioxidant action.

Functional foods for cardiovascular disease in women

Cardiovascular disease (CVD) is the leading cause of death in women. Functional food consumption can play an important role in the prevention and treatment of CVD. The purpose of this review is to establish recommendations for the intake of functional food ingredients in a healthy diet, such as soy proteins and isoflavone, omega-3 fatty acids (FAs) from fish oils (FOs) including eicosapentaenoic acid (EPA) and docoshexaenoic acid (DHA) and plant sterols-(PS) enriched foods – for prevention and treatment of CVD in postmenopausal women. First, controversial results exist on CVD risk factors after intake of soy protein and isoflavone that indicates that further clinical studies need to be done to better understand their role in maintaining and improving cholesterol levels. However, since soy contains polyunsaturated fats, replacing some higher fat meat protein sources with soy products may contribute to cardiovascular health. Secondly, FOs, including EPA and DHA, have shown promising effects for lowering triglyceride levels. In addition, emerging research appears to show that omega-3 FAs may have additional health effects with improved arterial health and a reduction in oxidative stress in postmenopausal women. Thirdly, foods and beverages supplemented with PS may reduce cholesterol; therefore, are a worthy addition to interventions aimed at lowering heart disease risk in women. Overall, incorporating functional foods into a healthy diet may be beneficial in helping to reduce lipids levels and thus the risk of CVD.

Pasta naturally enriched with isoflavone aglycons from soy germ reduces serum lipids and improves markers of cardiovascular risk

Most studies of soy and cholesterol have tested foods made from purified soy proteins containing mainly isoflavone glycosides. Fermented soy foods have mainly isoflavone aglycons and account for a high proportion of the soy protein source in Asia, where there is an inverse relationship between soy intake and serum cholesterol. The aim of this study was to compare a novel soy germ pasta, naturally enriched in isoflavone aglycons as a result of the manufacturing process, with conventional pasta for effects on serum lipids and other cardiovascular risk markers. In this randomized, controlled, parallel study design of 62 adults with hypercholesterolemia who consumed a Step II diet that included one 80-g serving/d of pasta, we measured serum lipids, high sensitivity C-reactive protein (hsCRP), urinary isoprostanes, and brachial artery flow-mediated vasodilatation at baseline and after 4 and 8 wk. The pasta delivered 33 mg of isoflavones and negligible soy protein and led to a serum isoflavone concentration of 222 +/- 21 nmol/L; 69% of subjects were equol producers. Soy germ pasta reduced serum total and LDL cholesterol by 0.47 +/- 0.13 mmol/L (P = 0.001) and 0.36 +/- 0.10 mmol/L (P = 0.002) more than conventional pasta, representing reductions from baseline of 7.3% (P = 0.001) and 8.6% (P = 0.002), respectively. Arterial stiffness (P = 0.003) and hsCRP (P = 0.03) decreased and improvements in all the above risk markers were greatest in equol producers. All measures returned to baseline when patients were switched to conventional pasta. In conclusion, pasta naturally enriched with isoflavone aglycons and lacking soy protein had a significant hypocholesterolemic effect beyond a Step II diet and improved other cardiovascular risk markers.

Isoflavones--safe food additives or dangerous drugs?

The sales volume of products containing isoflavone has increased since the publication of the Women's Health Initiative. The many apparently contradictory results published on the effects of isoflavones on a variety of estrogen-regulated organs point to both beneficial as well as adverse effects on human health. It is of particular importance that psychovegetative climacteric complaints such as hot flushes are, if at all, only slightly influenced by isoflavones. The substances appear to have weak anti-osteoporotic effect. Their anti-atherosclerotic action is debatable, as not all authors find any beneficial effect on lipids. Most importantly, there is dispute as to whether isoflavones derived from soy or red clover have negative, positive or any effect at all on the mammary gland or endometrium. It is beyond any doubt that soy products may have cancer preventing properties in a variety of organs including the mammary gland. However, these properties may only be exerted if the developing organ was under the influence of isoflavones during childhood and puberty. This may also explain the often quoted "Japanese Phenomenon", the fact that breast cancer occurs to a lesser extent in Japanese women. When administered to isoflavone "inexperienced" women at the time of menopause, the phytoestrogens appear to share the same effects as estrogen used in classical preparations for hormone replacement therapy, i.e. they may stimulate the proliferation of endometrial and mammary gland tissue with at present unknown and unpredictable risk to these organs. Therefore, the following question arises for the clinician: Why should soy or red clover products containing isoflavone be recommended, if the positive effects are only negligible but the adverse effects serious?

Modificaciones en el perfil lipídico tras el consumo regular de conservas de pescado. Influencia de la adición de isoflavonas, ácidos grasos omega-3 y fitoesteroles

BACKGROUND AND OBJECTIVE

Changes in dietary habits are associated with an improvement of lipid profile. We decided to assess changes in lipid profile reached with a dietary enrichment with canned tuna in olive oil and compared them with those reached with canned tuna with additional supplementation.

SUBJECTS AND METHOD

In a prospective, randomized, single blind study, 400 participants were assigned to a daily intake of canned tuna in olive oil alone (control group) or enriched with: isoflavones, omega-3 fatty acids of phytosterols, during three months. Plasmatic lipid levels were measured before and after intervention. Changes of lipid levels between basal and final visits and differences between the 4 types of supplementations were evaluated.

RESULTS

The mean age of the study population was 53 years, 45% of them being males. In all 4 groups a significant reduction of total cholesterol, low-density lipoprotein (LDL)-cholesterol levels and total cholesterol/high-density lipoprotein (HDL)-cholesterol ratio was observed after 3 months of follow-up; there were no significant changes of triglycerides nor HDL-cholesterol levels. The comparison between different types of supplementation revealed that only phytosterols addition reached a greater reduction of total cholesterol and LDL-cholesterol levels than canned tuna in olive oil alone (p < 0.05), and the differences between the remaining 2 supplementations and the control group were not significant.

CONCLUSIONS

Regular intake of enrichment with canned tuna supplementation is associated with improvement of lipid profile. The addition of isoflavones, omega-3 fatty acids or phytosterols supplementations increases fish consume effect, although only the enrichment with phytosterols reaches significantly better results.

Dietary soya intake alters plasma antioxidant status and lipid peroxidation in postmenopausal women with the metabolic syndrome

Postmenopausal women with the metabolic syndrome are at high risk of oxidative stress. Several studies have suggested possible antioxidant properties of soya, but little evidence is available regarding the effect of soya on oxidative stress in postmenopausal women with the metabolic syndrome. The objective of the present study was to determine the effects of soya consumption on plasma total antioxidant capacity (TAC) and malondialdehyde (MDA) level in postmenopausal women with the metabolic syndrome. A randomised cross-over trial was undertaken on forty-two postmenopausal women with the metabolic syndrome. Participants were randomly assigned to consume a control (Dietary Approaches to Stop Hypertension; DASH) diet, a soya protein diet, or a soya nut diet, each for 8 weeks. Red meat in the DASH diet (one serving per d) was replaced by soya protein in the soya protein period and by soya nuts in the soya nut period. Significant differences between the end values of the control diet, soya protein diet and soya nut diet were seen for MDA (0.70, 0.64 and 0.63 mumol/l; global P < 0.01). The results also showed a significant difference between the end values for TAC (1950, 2030 and 2110 mumol/l, respectively; P < 0.01). The difference from control for TAC was +4.5 % (P < 0.01) in the soya nut period and +5.8 % (P < 0.01) in the soya protein regimen. Both soya nuts and soya protein decreased MDA significantly compared with the control diet (difference from control was - 7.9 % (P < 0.01) in the soya nut period and - 9.4 % (P < 0.01) in the soya protein diet). We conclude that soya consumption reduces plasma MDA and increases plasma TAC levels in postmenopausal women with the metabolic syndrome.

Soy isoflavones lower serum total and LDL cholesterol in humans: a meta-analysis of 11 randomized controlled trials

BACKGROUND

Clinical trials have reported the cholesterol-lowering effects of soy protein intake, but the components responsible are not known.

OBJECTIVE

This meta-analysis was primarily conducted to evaluate the precise effects of soy isoflavones on lipid profiles. The effects of soy protein that contains enriched and depleted isoflavones were also examined.

DESIGN

PUBMED was searched for English-language reports of randomized controlled trials published from 1990 to 2006 that described the effects of soy protein intake in humans. Eleven studies were selected for the meta-analysis.

RESULTS

Soy isoflavones significantly decreased serum total cholesterol by 0.10 mmol/L (3.9 mg/dL or 1.77%; P = 0.02) and LDL cholesterol by 0.13 mmol/L (5.0 mg/dL or 3.58%; P < 0.0001); no significant changes in HDL cholesterol and triacylglycerol were found. Isoflavone-depleted soy protein significantly decreased LDL cholesterol by 0.10 mmol/L (3.9 mg/dL or 2.77%; P = 0.03). Soy protein that contained enriched isoflavones significantly decreased LDL cholesterol by 0.18 mmol/L (7.0 mg/dL or 4.98%; P < 0.0001) and significantly increased HDL cholesterol by 0.04 mmol/L (1.6 mg/dL or 3.00%; P = 0.05). The reductions in LDL cholesterol were larger in the hypercholesterolemic subcategory than in the normocholesterolemic subcategory, but no significant linear correlations were observed between reductions and the starting values. No significant linear correlations were found between reductions in LDL cholesterol and soy protein ingestion or isoflavone intakes.

CONCLUSIONS

Soy isoflavones significantly reduced serum total and LDL cholesterol but did not change HDL cholesterol and triacylglycerol. Soy protein that contained enriched or depleted isoflavones also significantly improved lipid profiles. Reductions in LDL cholesterol were larger in hypercholesterolemic than in normocholesterolemic subjects.

Effect of soy protein from differently processed products on cardiovascular disease risk factors and vascular endothelial function in hypercholesterolemic subjects

BACKGROUND

The magnitude of the effect of soy protein on lipoprotein concentrations is variable. This discordance is likely attributable to the various forms of soy protein used and to unrecognized shifts in dietary fatty acid, cholesterol, and fiber.

OBJECTIVE

The objective was to evaluate the effect of soybean processing as well as soy consumption relative to animal protein, independent of alterations in major dietary variables, on cardiovascular disease risk factors and vascular endothelial function.

DESIGN

Twenty-eight hypercholesterolemic subjects (LDL cholesterol >/=3.36 mmol/L) aged >50 y consumed each of 4 diets for 6-wk periods according to a randomized crossover design. The diets [55% of energy as carbohydrate, 30% of energy as fat, and 15% of energy as protein-7.5% of energy as experimental protein (37.5 g/d)] were designed to contain products made from either whole soybeans, soyflour, or soymilk and were compared with a diet containing an equivalent amount of animal protein (meat, chicken, and dairy products). The cholesterol, fiber, and fatty acid profiles of the diets were equalized. All food and drink were provided, and body weight was maintained throughout the study.

RESULTS

No significant differences in blood pressure, vascular endothelial function, or total cholesterol, VLDL-cholesterol, triacylglycerol, apolipoprotein B, or C-reactive protein concentrations were observed between the diets. Consumption of the soymilk diet resulted in a modest decrease (4%) in LDL-cholesterol concentrations compared with the animal-protein and soyflour diets (P < 0.05) and higher HDL-cholesterol (1%) and apolipoprotein A-I (2%) concentrations compared with the soybean and soyflour diets (P < 0.05).

CONCLUSIONS

The results suggest that the consumption of differently processed soy-based products and different types of protein (animal and soy) has little clinical effect on cardiovascular disease risk factors, including peripheral endothelial function, when other major dietary variables are held constant.

Treatment of natto, a fermented soybean preparation, to prevent excessive plasma vitamin K concentrations in patients taking warfarin

The purpose of this study is to find a method of cooking natto that prevents the appearance of high-plasma vitamin K concentrations after the consumption of natto, so that patients taking warfarin can benefit from eating natto. Five cooking methods were examined to determine which could most effectively decrease the count of the living Bacillus subtilis in natto. Volunteers ate natto or treated natto, and their plasma vitamin K level was measured at 5, 8, 24 and 48 h thereafter. One gram of natto contained 9.7+/-0.1 Log cfu/mL of Bacillus subtilis. Boiling significantly reduced the Bacillus subtilis count to 5.1+/-0.3 Log cfu/mL, and concomitantly reduced the content of menaquinone-7 (MK-7), which is a form of vitamin K synthesized by Bacillus subtilis, from 660.40+/-65.32 ng/mL to 78.50+/- 11.12 ng/mL. Untreated natto increased the MK-7 concentration in blood from 1.86+/-1.51 ng/mL to 14.54+/-4.12 ng/mL at 5 h after intake, and the MK-7 concentration remained elevated at 8, 24 and 48 h (7.29+/-2.20, 6.97+/-2.60, and 5.37+/-1.94 ng/mL, respectively). In contrast, boiled natto increased plasma MK-7 only mildly (from 1.61+/-1.11 to 4.02+/-0.82 ng/ mL at 5 h) and the concentration remained relatively stable up to 48 h (3.46+/-0.83, 4.22+/-1.51 and 2.77+/-0.75 ng/mL at 8, 24 and 48 h, respectively). In conclusion, boiled natto did not cause a marked increase in the plasma concentration of vitamin K in subjects who consumed it. Thus, patients on warfarin may be able to eat boiled natto without ill effects.

Soy and red clover for mid-life and aging

INTRODUCTION

Menopause is associated with mid-life, a time when many women begin to experience the signs and symptoms of aging, such as increases in blood pressure, changes in lipid profiles, loss of bone mass density, and diminished memory and cognition. Given the result of the Women's Health Initiative, many women no longer consider hormone therapy the first option for promoting healthy aging. Instead, they are turning to botanical and dietary supplement (BDS) products in place of hormone therapy. This paper reviews the evidence available for use of isoflavones from soy and red clover for the treatment or prevention of these health issues.

METHODS

The MEDLINE and EMBASE databases were searched for articles relating to soy or red clover supplement use for prevention and/or treatment of heart disease, hyperlipidemia, osteoporosis, mood disorders and cognitive abilities. Studies were included if they were randomized, controlled trials and included peri- or postmenopausal women.

RESULTS

Isoflavone products appear to be the most useful for improving lipid profiles; however, the evidence suggests that isoflavone extracts from soy are less effective than products containing soy protein or red clover isoflavones. Soy protein appears to reduce levels of total cholesterol and low density lipoprotein cholesterol, while red clover reduces levels of triglycerides and increases high density lipoprotein cholesterol. The data were somewhat less convincing, although promising, for increasing bone mass density and improving cognitive abilities.

CONCLUSIONS

Research suggests that isoflavones found in soy foods and red clover appear to have a small but positive health effect on plasma lipid concentrations, bone mass density, and cognitive abilities. Given the lack of serious safety concerns in the short term, it would appear that including soy and red clover in the diet of postmenopausal women, not withstanding a soy allergy, might be beneficial.

Effects of soy isoflavones and phytate on homocysteine, C-reactive protein, and iron status in postmenopausal women

BACKGROUND

Soy protein or its components may protect against the atherosclerotic cardiovascular disease (CVD) risk factors total homocysteine (tHcy), C-reactive protein (CRP), and excess body iron, which generally increase with menopause.

OBJECTIVE

The primary objective of this study was to determine the independent effect of the soy protein components isoflavones and phytate on CVD risk factors in postmenopausal women. The secondary objective was to identify factors [blood lipids, oxidative stress indexes, serum ferritin, plasma folate, plasma vitamin B-12, and body mass index (BMI)] contributing to tHcy and CRP concentrations.

DESIGN

In a double-blind, 6-wk study, 55 postmenopausal women aged 47-72 y were randomly assigned to 1 of 4 soy protein (40 g/d) isolate treatments: native phytate and native isoflavone (n = 14), native phytate and low isoflavone (n = 13), low phytate and native isoflavone (n = 14), or low phytate and low isoflavone (n = 14). We measured iron indexes, tHcy, CRP, and BMI.

RESULTS

Soy protein with native phytate significantly reduced tHcy (P = 0.017), transferrin saturation (P = 0.027), and ferritin (P = 0.029), whereas soy protein with native isoflavones had no effect on any variables. At baseline, BMI was highly correlated with tHcy (r = 0.39, P = 0.003) and CRP (r = 0.55, P < 0.0001), whereas HDL cholesterol was correlated with CRP (r = -0.30, P = 0.02). Multiple regression analysis showed that LDL cholesterol and BMI contributed significantly (R2= 19.9%, P = 0.003) to the overall variance in tHcy.

CONCLUSION

Consuming phytate-rich foods and maintaining a healthy weight may reduce atherosclerotic CVD risk factors in postmenopausal women.

Soy protein containing isoflavones favorably influences macrophage lipoprotein metabolism but not the development of atherosclerosis in CETP transgenic mice

The possibility that soy protein containing isoflavones influences the development of experimental atherosclerosis has been investigated in ovariectomized mice heterozygous for the human CETP transgene and for the LDL-receptor null allele (LDLr(+/-) CETP(+/-)). After ovariectomy at 8 wk of age they were fed a fat/cholesterol-rich diet for 19 wk and divided into three experimental groups: dietary unmodified soy protein containing isoflavones (mg/g of diet), either at low-dose (Iso Low, 0.272, n = 25), or at high-dose (Iso High, 0.535, n = 28); and the atherogenic diet containing an isoflavone-depleted alcohol-washed soy protein as a control group (n = 28). Aortic root lipid-stained lesion area (mean microm2 x 10(3) +/- SD) did not differ among Iso Low (12.3 +/- 9.9), Iso High (7.4 +/- 6.4), and controls (10.7 +/- 12.8). Autoantibody titers against plasma oxidized LDL did not differ among the experimental groups. Using the control mice as the reference value (100%), in vitro mouse peritoneal macrophage uptake of labeled acetylated LDL-cholesterol was lower in the Iso High (68%) than in the Iso Low (85%) group. The in vitro percent removal by exogenous HDL of labeled unesterified cholesterol from macrophages previously enriched with human [4- 14C]-cholesteryl oleate acetylated LDL was enhanced in the Iso High group (50%). In spite of these in vitro potentially antiatherogenic actions, soy protein containing isoflavones did not modify the average size of lipid-stained area in the aortic root.

Cautions in the use of biomarkers of oxidative damage; the vascular and antioxidant effects of dark soy sauce in humans

Dark soy sauce (DSS) is a powerful antioxidant in vitro. We investigated whether this effect could occur in vivo and improve vascular function. Healthy human subjects were given DSS or placebo meals in a randomized, crossover study. Blood and urine were sampled before and 1, 2, 3, and 4h after the meal for F(2)-isoprostanes (total, free, and esterified) and 8OHdG measurements. Blood pressure, vascular augmentation index (AIx), and heart rate (HR) were also measured. Plasma total F(2)-isoprostanes significantly decreased 3h after placebo and the decrease was greater for DSS. Plasma free and esterified F(2)-isoprostanes were also significantly decreased after DSS. Both placebo and DSS meals increased urinary F(2)-isoprostanes at 1h but not thereafter, and lowered urinary 8OHdG levels, DBP and AIx, and increased HR. We conclude that DSS decreases lipid peroxidation in vivo. However, oxidative damage biomarkers changed after the placebo meal, a phenomenon to consider when designing interventional studies.

Soy protein with and without isoflavones fails to substantially increase postprandial antioxidant capacity

Five methods for the assessment of antioxidant capacity [whole plasma conjugated diene formation, low-density lipoprotein oxidation susceptibility, ferric-reducing ability of plasma, oxygen radical absorbance capacity and perchloric-acid-treated oxygen radical absorbance capacity (PCA-ORAC)] were used in a randomized, double blind, crossover study to determine the acute postprandial antioxidant protection imparted by the isoflavone component of soy. On separate days, 16 subjects consumed one of three isocaloric shakes containing 25 g of protein in the form of soy, with 107 mg of total aglycone units of isoflavones, soy with trace isoflavones (<4 mg) or total milk protein. Blood was collected at baseline, 4 h, 6 h and 8 h after consumption. Antioxidant capacity, serum isoflavone levels, fat-soluble antioxidants and plasma vitamin C levels were evaluated. Repeated measures analysis of variance showed no significant differences (P=.05) within treatments over time in four of five antioxidant capacity measurements. Significant differences over time between the soy with trace isoflavones and the total milk protein group were observed using the PCA-ORAC assay. It can be concluded that, on an acute basis, a significant increase in serum antioxidant capacity is not detectable following consumption of soy protein.

[Effects on health of soy in menopausic women]

Phystestrogens are organic compounds produced by a large variety of plants with protective function against the invasion of them by microorganisms. Phystestrogens, and among them isoflavones, have a great similarity with estradiol, principal endogenous estrogen. Those known most for their estrogenic activity are daidzeine and genisteine. Due to the existence of contradictory data on the effects of soy isoflavones on the most outstanding health disorders of menopause such as osteoporosis and hot flushes, and its ineffective role in the improvement of the lipid profile, it is recommendable to continue choosing hygienic-dietary and conventional drug treatments. However, we could introduce soy and soy derived products within a balanced, varied and adequate diet for these women.

Effects of soy or milk protein durign a high-fat feeding challenge on oxidative stress, inflammation, and lipids in healthy men

Soy isoflavones may impede atherogenic processes associated with cardiovascular disease. Research suggests that the postprandial generation of TG-rich remnants contributes to the development of atherosclerosis. The purpose of the current study was to determine if 39 g soy (85 mg aglycone isoflavones, treatment) compared with 40 g milk protein (0 mg aglycone isoflavones, control) in combination with a high-fat meal can modify postprandial, atherogenic-associated events and biomarkers for oxidative stress, inflammation, and thrombosis. Fifteen healthy men (20-47 yr) participated in a double-blind cross-over meal-challenge study occurring on two nonconsecutive days. The study meals consisted of two high-fat apple muffins consumed with either a soy or milk shake (229 mL, 41% fat, 41% carbohydrate, and 18% protein). Blood samples were obtained at baseline (fasted) and hours two, four, and six postprandial. Plasma TG significantly increased in both treatment and control meal challenges compared with baseline. There were no significant differences (P > 0.05) between treatment (soy) and control (milk) for ex vivo copper-induced LDL oxidation, serum C-reactive protein, serum interleukin-6 (IL-6), serum fibrinogen, or plasma lipids (total cholesterol, HDL, LDL, TG). IL-6-concentrations significantly decreased as a function of time during either meal challenge (P = 0.005). These data suggest that consumption of soy or milk protein in conjunction with a high-fat meal does not acutely modify postprandial oxidative stress, inflammation, or plasma lipid concentrations in young, healthy men.