RESUMO
BACKGROUND: Clinical studies have reported the beneficial effects of unfermented soy product consumption on blood lipids in various populations. However, contradictory results have been reported regarding the influence of unfermented soy product consumption on blood lipids in postmenopausal women. OBJECTIVE: The aim of this systematic review and meta-analysis was to evaluate the effects of diets with unfermented soy products compared with diets without unfermented soy products on blood lipids in postmenopausal women. METHODS: The Cochrane Library, PubMed, Scopus, Web of Science, and Embase electronic databases were searched for eligible randomized controlled trials (RCTs) published up to February 21, 2023. RCTs were included if they were published in English and investigated the effect of unfermented soy product consumption on blood lipids in postmenopausal women who had discontinued hormone replacement therapy at least 3 months before randomization. A random-effects model was used to calculate the overall effect size of the mean difference (MD) and 95% CI. Risk of bias was assessed using the Cochrane Risk-of-Bias Tool for Randomized Trials, version 2. RESULTS: Twenty-nine RCTs involving 2,457 participants were included. The results showed that, compared with the control group that did not consume unfermented soy products, consumption of unfermented soy products significantly reduced total cholesterol (TC) (MD, -9.46 mg/dL [to convert mg/dL cholesterol to mmol/L, multiply mg/dL by 0.0259; to convert mmol/L cholesterol to mg/dL, multiply by 38.7]; 95% CI -15.04 to -3.89 mg/dL; P = .001) and triglycerides (TGs) (MD, -10.86 mg/dL [to convert mg/dL TGs to mmol/L, multiply mg/dL by 0.0113; to convert mmol/L TGs to mg/dL, multiply mmol/L by 88.6]; 95% CI -19.70 to -2.02 mg/dL; P = .016), while significantly increasing high-density lipoprotein cholesterol (MD, 2.32 mg/dL; 95% CI 0.87 to 3.76 mg/dL; P = .002) in postmenopausal women, but had no significant effect on low-density lipoprotein cholesterol (MD, -4.55 mg/dL; 95% CI -10.90 to 1.80 mg/dL; P = .160). Results of soy preparation subgroup analysis showed that soy isolate protein significantly reduced TC and soy protein-containing isoflavones significantly reduced TC and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Furthermore, unfermented soy product consumption significantly reduced TC, low-density lipoprotein cholesterol, and TG levels in postmenopausal women with lipid disorders and TGs in healthy postmenopausal women. CONCLUSIONS: The results showed that unfermented soy product consumption reduced TC and TG levels significantly, and increased high-density lipoprotein cholesterol levels in postmenopausal women. The findings of this review contribute to the evidence-base for dietary management of blood lipids in postmenopausal women.
RESUMO
As one of the most significant probiotics, Limosilactobacillus reuteri (L. reuteri) has been exploited as a nutritional supplement. We hypothesized that L. reuteri consumption might improve the significant risk factors of cardiovascular disease, including blood pressure, blood lipid, and blood glucose. However, previous clinical studies have shown controversial results. This study aims to explore the effect of L. reuteri consumption on these risk factors. PubMed, Embase, Scopus, the Cochrane Library, and Web of Science were searched for eligible randomized controlled trials published before May 2022. A total of 6 studies with 4 different L. reuteri strains and including 512 participants were included. The results showed that L. reuteri consumption significantly reduced total cholesterol (TC) by -0.26 mmol/L compared with the control group. In contrast, it did not affect systolic blood pressure, diastolic blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), or triglycerides. Subgroup analysis showed a significant reduction in TC when participants were <55 years old, had a body mass index between 25 and 30, or had hypercholesterolemia. In addition, TC decreased significantly when L. reuteri supplementation was >5 × 109 colony-forming unit or the length of the intervention was <12 weeks. Strain subgroup analysis showed that L. reuteri NCIMB 30242 significantly reduced TC and LDL-C. In conclusion, L. reuteri consumption has a significant TC-lowering effect, which can effectively reduce the risks of cardiovascular disease associated with hypercholesterolemia. However, the results do not support the effectiveness of L. reuteri consumption on other metabolic outcomes. Further examination of larger sample sizes is needed to confirm these findings.
