-
1.
Coffee Consumption and Risk of Hypertension in Adults: Systematic Review and Meta-Analysis.
Haghighatdoost, F, Hajihashemi, P, de Sousa Romeiro, AM, Mohammadifard, N, Sarrafzadegan, N, de Oliveira, C, Silveira, EA
Nutrients. 2023;15(13)
-
-
-
Free full text
Plain language summary
High blood pressure (hypertension) is the main risk factor for cardiovascular diseases. Over the past decades the number of people experiencing high blood pressure has steadily increased, making it a serious concern for public health. Many dietary factors influence the development of high blood pressure, either increasing of decreasing the risk. Coffee is a widely consumed beverage. The caffeine in coffee can stimulate stress hormones like adrenaline. Adrenaline increases blood pressure, inflammation and decreases sensitivity to insulin, which are all regarded as risk factors for cardiovascular diseases. At the same time coffee contains many blood pressure lowering nutrients and compounds. Whether coffee contributes or diminishes the risks of developing high blood pressure has remained controversial. Hence, this systematic review and meta-analysis aimed to summarise the current evidence on coffee and hypertension risk. The analysis included 25 observational studies published between 2002 and 2023. The results concluded that coffee consumption was associated with a small reduction in risk for high blood pressure development. An inverse association was found, suggesting that as coffee consumption rose, high blood pressure risk falls. However, upon closer examination this inverse relationship was only found in the USA, but not in Europe and Asia. The authors suggested that geographics, genetics, gender, coffee preparation methods, and differences in lifestyle habits (smoking, salt consumption etc.) may contribute to the discrepancies between outcomes and make it harder to compare studies to form a uniform consensus. Hence, they urged for a cautious interpretation of the findings. In the absence of clear, consistent evidence, coffee consumption and cardiovascular risk may need to be assessed on an individual basis in clinical practice.
Abstract
OBJECTIVES The association between coffee intake and hypertension (HTN) risk is controversial. Therefore, this systematic review and meta-analysis aimed at summarizing the current evidence on the association of coffee with hypertension risk in observational studies. METHODS PubMed/Medline and Web of Science were searched for observational studies up to February 2023. Observational studies which assessed the risk of HTN in the highest category of coffee consumption in comparison with the lowest intake were included in the current meta-analysis (registration number: CRD42022371494). The pooled effect of coffee on HTN was evaluated using a random-effects model. RESULTS Twenty-five studies i.e., thirteen cross-sectional studies and twelve cohorts were identified to be eligible. Combining 13 extracted effect sizes from cohort studies showed that higher coffee consumption was associated with 7% reduction in the risk of HTN (95% CI: 0.88, 0.97; I2: 22.3%), whereas combining 16 effect sizes from cross-sectional studies illustrated a greater reduction in HTN risk (RR = 0.79, 95% CI: 0.72, 0.87; I2 = 63.2%). These results varied by studies characteristics, such as the region of study, participants' sex, study quality, and sample size. CONCLUSIONS An inverse association was found between coffee consumption and hypertension risk in both cross-sectional and cohort studies. However, this association was dependent on studies characteristics. Further studies considering such factors are required to confirm the results of this study.
-
2.
Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention.
Li, S, Yin, S, Ding, H, Shao, Y, Zhou, S, Pu, W, Han, L, Wang, T, Yu, H
Cell proliferation. 2023;56(1):e13346
-
-
-
Free full text
-
Plain language summary
Multiple risk factors could lead to the development of liver cancer, one of the most common malignant tumours in the world. These risk factors include hepatitis infection, non-alcoholic fatty liver disease and excessive alcohol consumption. Polyphenols are bioactive compounds with antioxidant, anti-inflammatory, anti-mutagenic, anti-viral, hypoglycaemic, anti-hypertensive, antibacterial and anti-proliferative properties. Polyphenols may be effective in reducing the risk of developing liver cancer by altering the metabolism. This review evaluated the effectiveness of polyphenols in protecting the liver and inhibiting hepatocarcinoma development. In addition, the review evaluated several mechanisms by which polyphenols affect glucose and lipid metabolism and mitochondrial metabolism and reduce the effects of oxidative stress, inflammation and toxic metabolites. Further robust studies are required to assess the beneficial effects of polyphenols as a therapeutic agent, as the current knowledge is limited. However, healthcare professionals can use the results of this study to understand the protective effects of polyphenols against liver disease.
Abstract
BACKGROUND Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation. METHODS We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention. RESULTS Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer. CONCLUSION This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.
-
3.
Polyphenol Intake in Pregnant Women on Gestational Diabetes Risk and Neurodevelopmental Disorders in Offspring: A Systematic Review.
Salinas-Roca, B, Rubió-Piqué, L, Montull-López, A
Nutrients. 2022;14(18)
-
-
-
Free full text
Plain language summary
In Europe, gestational diabetes affects approximately 10.9% of pregnant women. According to previous research, the cardiometabolic health of the mother and the mother's dietary habits during pregnancy may affect the foetus' neurodevelopment. Taking polyphenol supplements and eating foods rich in polyphenols is beneficial for promoting health across generations. In this systematic review, fourteen studies were included in order to evaluate the effects of polyphenols on gestational diabetes and mental health in the offspring. A higher prevalence of neurodevelopmental diseases in offspring is associated with gestational diabetes. The results of this systematic review revealed that polyphenol intake during pregnancy might have a beneficial effect on improving cardiometabolic health, reducing inflammation, DNA methylation and oxidative stress, thus reducing the risk of developing fetal neurodevelopmental disorders, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorders. There is a need for further robust research, as the existing evidence regarding the safety of long-term polyphenol supplementation and its effects on gestational diabetes and fetal neurodevelopment is very limited. In spite of this, healthcare professionals can use the findings of this systematic review to learn more about the positive health benefits of polyphenols in pregnant women.
Abstract
The intake of foods containing polyphenols can have a protective role to avoid comorbidities during pregnancy and, at the same time, promote transgenerational health. This review aims to describe the effect of polyphenol intake through supplements or polyphenol-rich foods during pregnancy on the incidence and evolution of gestational diabetes mellitus (GDM), as well as the link with the neurodevelopment of the fetus. Using PRISMA procedures, a systematic review was conducted by searching in biomedical databases (PubMed, Cinahl and Scopus) from January to June 2022. Full articles were screened (n = 419) and critically appraised. Fourteen studies were selected and were divided into two different thematic blocks considering (i) the effect of polyphenols in GDM and (ii) the effect of GDM to mental disorders in the offspring. A positive relationship was observed between the intake of polyphenols and the prevention and control of cardiometabolic complications during pregnancy, such as GDM, which could be related to thwarted inflammatory and oxidative processes, as well as neuronal factors. GDM is related to a greater risk of suffering from diseases related to neurodevelopment, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorder. Further clinical research on the molecule protective mechanism of polyphenols on pregnant women is required to understand the transgenerational impact on fetal neurodevelopment.
-
4.
Consumption of flavonoids and risk of hormone-related cancers: a systematic review and meta-analysis of observational studies.
Liu, F, Peng, Y, Qiao, Y, Huang, Y, Song, F, Zhang, M, Song, F
Nutrition journal. 2022;21(1):27
-
-
-
-
Free full text
Plain language summary
Hormone-related cancers (HRCs) are greatly influenced by hormone levels and generally respond to hormone regulation, which plays an indispensable role in tumour growth. Encouragingly, diets rich in vegetables, fruits and tea are found to reduce the cancer risk, having the potential to exert chemo-preventive effects with the presence of anticarcinogenic phytochemicals. The aim of this study was to elucidate the association between flavonoids intake and HRCs risk. This study is a meta-analysis of fifty-one studies. It consisted of 22 prospective cohort studies, 1 nested case–control study, 18 population-based case–control studies and 10 hospital-based case–control studies. Results show that higher consumption of total flavonoids was only associated with an increased risk of men-specific cancers, mainly prostate cancer. Furthermore, the subclasses, flavanols, flavones, and isoflavones, and the three main individual compounds of isoflavones (daidzein, genistein and glycitein) may have protective effects on women-specific cancers, whereas flavones and flavanones have been found to cause potentially dangerous effects in thyroid cancer. Additionally, there was no evidence in support of any role for anthocyanidins in HRCs. Authors conclude that there is a small amount of evidence that total flavonoids, flavanols, flavones, flavanones, flavan-3-ols and isoflavones may be associated with a lower or higher risk of certain HRCs, which may provide guidance for dietary guidelines to a certain extent in the future.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Dietary flavonoids are widely available in plant-based foods such as vegetables, citrus fruits, green tea and berries
- Menopausal status may be an important consideration for flavonoid intake when considering breast cancer risk
- Differences in results for Asians and non-Asians need to be considered for the use of flavonoids in women-specific hormonal cancers and prostate cancer in men
- Caution should be exercised when considering flavones and flavanones and thyroid cancer risk until further research is available
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Background
Hormone-related cancers (HRCs) are the most frequently diagnosed cancers globally , accounting for more than a quarter of new cancer cases worldwide in 2018. They include breast, ovarian, endometrial, prostate, testicular and thyroid cancer which share a similar carcinogenic mechanism. Diets rich in vegetables, fruit, legumes and tea may reduce cancer risk due to anticarcinogenic phytochemicals, such as flavonoids. Flavonoids are claimed to have many different physiological and pathological functions in the cancer process, including tumour cell proliferation, inflammation, angiogenesis, invasion and metastasis.. This study aimed to summarise the relationships between consumption of flavonoids with the risk of HRC.
Methods:
The meta-analysis was carried out following PRISMA guidelines and registered on PROSPERO. A literature search in PubMed and Embase was conducted using the keywords flavonoids, flavanols and isoflavones and breast, ovarian, endometrial, prostate, testicular and thyroid cancer. 51 studies published between 1999 and 2022 consisted of 22 prospective cohort, 18 population-based and 10 hospital-based case-control studies. On the Newcastle-Ottawa Scale assessment all studies were of medium or high methodological quality.
Results:
Results were analysed using Stata 15.1 software and ORs with 95% CIs used to measure the association between flavonoid intake and HRCs risk. Statistical I2 evaluated heterogeneity among the studies.
Funnel plots were inspected for publication bias and calculated by Begg’s/Egger’s regression tests. Sensitivity analyses were performed to explore the source of heterogeneity. Subgroup analysis was performed on study design and region, as well as menopausal status.
Higher consumption of flavonoids was associated with a decreased risk of women-specific cancers but a significant elevated risk of prostate cancer as seen below.
Women specific cancers:
For flavonoid sub-classes, higher consumption of flavanols (OR=0.85; 95% CI, 0.76–0.94; I2=75.5%; p<0.001), flavones (OR=0.85; 95% CI, 0.77–0.95; I2=76.3%; p<0.001) and isoflavones (OR=0.87; 95% CI, 0.82–0.92; I2=73.8%; p<0.001) was associated with a decreased risk of women-specific cancers (breast, ovarian and endometrial), especially among the case–control studies. Similar results were seen in the main compounds of isoflavones: daidzen, genistein and glycitein. There were differences in the association between isoflavones in Asian and non-Asian regions.
Men-specific cancers:
The higher consumption of total flavonoids (OR=1.11; 95% CI, 1.02–1.21; I2 = 0%; p = 0.484) was associated with an increased risk of prostate cancer and this was only found in non-Asian populations.
Conclusion:
Despite limitations of the meta-analysis, such as the use of observational studies and small sample sizes of the included studies, this systematic review may provide some preliminary dietary evidence for the use of flavonoids in HRCs.
Clinical practice applications:
- The promotion of a plant-based diet, rich in vegetables, fruits, green tea and legumes may have protective effects on women-specific cancers due to the rich presence of flavanols, flavones and isoflavones, as well as the compounds genistein, glycitein and daidzein.
- Results show no associations between total flavonoids intake and women-specific cancer however, the sub-groups of flavanols, flavones and isoflavones were associated with a decreased risk in women-specific cancers. Similar results were seen in the individual compounds of isoflavones: genistein, glycitein and daidzein. These results may guide decision-making when recommending the inclusion of these compounds for protective benefits in women-specific cancers.
- The positive association between total flavonoids and prostate cancer risk was only seen in non-Asians, and between higher consumption of flavones and flavanones and thyroid cancer risk albeit in limited studies (n=3) may provide important guidelines when considering which foods to include from a plant-based diet.
Considerations for future research:
- Further meta-analysis of prospective studies with larger sample sizes
- The use of a validated and reliable questionnaire for measuring flavonoid intake
- Intervention studies evaluating flavonoid subclasses
- Comparisons between Asian and non-Asian populations
- Consideration of menopausal status as an effect modifier
Abstract
BACKGROUND Flavonoids seem to have hormone-like and anti-hormone properties so that the consumption of flavonoids may have potential effects on hormone-related cancers (HRCs), but the findings have been inconsistent so far. This meta-analysis was aimed to explore the association between flavonoids intake and HRCs risk among observational studies. METHODS Qualified articles, published on PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) from January 1999 to March 2022 and focused on relationships between flavonoids (total, subclass of and individual flavonoids) and HRCs (breast, ovarian, endometrial, thyroid, prostate and testicular cancer), were retrieved for pooled analysis. Random effects models were performed to calculate the pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Funnel plots and Begg's/Egger's test were used to evaluate the publication bias. Subgroup analyses and sensitivity analyses were conducted to explore the origins of heterogeneity. RESULTS All included studies were rated as medium or high quality. Higher consumption of flavonols (OR = 0.85, 95% CI: 0.76-0.94), flavones (OR = 0.85, 95% CI: 0.77-0.95) and isoflavones (OR = 0.87, 95% CI: 0.82-0.92) was associated with a decreased risk of women-specific cancers (breast, ovarian and endometrial cancer), while the higher intake of total flavonoids was linked to a significantly elevated risk of prostate cancer (OR = 1.11, 95% CI: 1.02-1.21). A little evidence implied that thyroid cancer risk was augmented with the higher intake of flavones (OR = 1.24, 95% CI: 1.03-1.50) and flavanones (OR = 1.31, 95% CI: 1.09-1.57). CONCLUSIONS The present study suggests evidence that intake of total flavonoids, flavonols, flavones, flavanones, flavan-3-ols and isoflavones would be associated with a lower or higher risk of HRCs, which perhaps provides guidance for diet guidelines to a certain extent. TRIAL REGISTRATION This protocol has been registered on PROSPERO with registration number CRD42020200720 .
-
5.
Efficacy and safety of dietary polyphenol supplementation in the treatment of non-alcoholic fatty liver disease: A systematic review and meta-analysis.
Yang, K, Chen, J, Zhang, T, Yuan, X, Ge, A, Wang, S, Xu, H, Zeng, L, Ge, J
Frontiers in immunology. 2022;13:949746
-
-
-
Free full text
Plain language summary
Non-alcoholic fatty liver disease (NAFLD) is characterised by fat accumulation in the liver that can result in liver damage. NAFLD affects approximately 25% of the global population. There is evidence that dietary polyphenols can improve metabolism and insulin resistance and reduce inflammation and oxidative stress, which are the mechanisms that lead to liver damage in NAFLD. This systematic review and meta-analysis aimed to assess the effectiveness of dietary polyphenols in the treatment of non-alcoholic fatty liver disease (NAFLD). Eight dietary polyphenols, such as curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein, were evaluated for their efficacy and safety. The administration of 80-3,000 mg of Curcumin for an 8-12 week duration is effective and safe for reducing body mass index, aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides (TG), total cholesterol (TC), and insulin resistance (HOMA-IR). Compared with the placebo, Naringenin reduced the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Hesperidin may potentially decrease body mass index (BMI), AST, ALT, TG, TC, and HOMA-IR. Catechin is safe, and 500-1000 mg supplementation for 12 weeks may reduce BMI, HOMA-IR, and TG. NAFLD patients who received silymarin showed improvements in ALT and AST, as well as reductions in hepatic fat accumulation and liver stiffness. 94–2100 mg of Silymarin supplementation for 8–48 weeks may reduce liver enzyme levels. Researchers can use the results of this study to understand the clinical utility of different polyphenol supplements in the treatment of NAFLD. Because the current evidence is highly heterogeneous in nature and limited in scope, further robust research is required on various classes of polyphenols and their effectiveness in reducing the severity of NAFLD.
Abstract
Background: Dietary polyphenol treatment of non-alcoholic fatty liver disease (NAFLD) is a novel direction, and the existing clinical studies have little effective evidence for its therapeutic effect, and some studies have inconsistent results. The effectiveness of dietary polyphenols in the treatment of NAFLD is still controversial. The aim of this study was to evaluate the therapeutic efficacy of oral dietary polyphenols in patients with NAFLD. Methods: The literature (both Chinese and English) published before 30 April 2022 in PubMed, Cochrane, Medline, CNKI, and other databases on the treatment of NAFLD with dietary polyphenols was searched. Manual screening, quality assessment, and data extraction of search results were conducted strictly according to the inclusion and exclusion criteria. RevMan 5.3 software was used to perform the meta-analysis. Results: The RCTs included in this study involved dietary supplementation with eight polyphenols (curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein) and 2,173 participants. This systematic review and meta-analysis found that 1) curcumin may decrease body mass index (BMI), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Triglycerides (TG) total cholesterol (TC), and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) compared to placebo; and curcumin does not increase the occurrence of adverse events. 2) Although the meta-analysis results of all randomized controlled trials (RCTs) did not reveal significant positive changes, individual RCTs showed meaningful results. 3) Naringenin significantly decreased the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) but had no significant effect on AST and ALT, and it is a safe supplementation. 4) Only one team presents a protocol about anthocyanin (from Cornus mas L. fruit extract) in the treatment of NAFLD. 5) Hesperidin may decrease BMI, AST, ALT, TG, TC, HOMA-IR, and so on. 6) Catechin may decrease BMI, HOMA-IR, and TG level, and it was well tolerated by the patients. 7) Silymarin was effective in improving ALT and AST and reducing hepatic fat accumulation and liver stiffness in NAFLD patients. Conclusion: Based on current evidence, curcumin can reduce BMI, TG, TC, liver enzymes, and insulin resistance; catechin can reduce BMI, insulin resistance, and TG effectively; silymarin can reduce liver enzymes. For resveratrol, naringenin, anthocyanin, hesperidin, and catechin, more RCTs are needed to further evaluate their efficacy and safety.
-
6.
Buckwheat and Cardiometabolic Health: A Systematic Review and Meta-Analysis.
Llanaj, E, Ahanchi, NS, Dizdari, H, Taneri, PE, Niehot, CD, Wehrli, F, Khatami, F, Raeisi-Dehkordi, H, Kastrati, L, Bano, A, et al
Journal of personalized medicine. 2022;12(12)
-
-
-
Free full text
Plain language summary
Buckwheat is a gluten-free, pseudo-grain rich in bioactive compounds that are cardiometabolic health protective. Bioactive cardioprotective compounds include proteins, fibre, and polyphenols such as rutin and quercetin-3-glucoside. This systematic review and meta-analysis investigated the supplementation and consumption of buckwheat and its effects on cardiovascular risk markers. Sixteen studies were included in the systematic review, and ten were included in the meta-analysis. This systematic review and meta-analysis showed a modest, non-significant improvement in total cholesterol and glucose levels. Further robust studies are required to investigate the beneficial effects of bioactive compounds found in buckwheat due to the high heterogeneity of the included studies and the poor quality of the included studies. However, healthcare professionals can use the results of this research to understand the potential of buckwheat in improving or maintaining cardiometabolic health.
Abstract
Buckwheat (BW) is suggested to have beneficial effects, but evidence on how it affects cardiometabolic health (CMH) is not yet established. We aimed to assess the effects of BW and/or its related bioactive compounds on cardiovascular disease (CVD) risk markers in adults. Five databases were searched for eligible studies. Observational prospective studies, nonrandomized or randomized trials were considered if they assessed BW, rutin or quercetin-3-glucoside intake and CVD risk markers. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting. We selected 16 human studies based on 831 subjects with mild metabolic disturbances, such as hypercholesterolemia, diabetes and/or overweight. Eight studies, investigating primarily grain components, were included in the meta-analyses (n = 464). High study heterogeneity was present across most of our analyses. Weighted mean difference (WMD) for subjects receiving BW supplementation, compared to controls, were - 0.14 mmol/L (95% CI: -0.30; 0.02) for total cholesterol (TC), -0.03 mmol/L (95% CI: -0.22; 0.16) for LDL cholesterol, -0.14 kg (95% CI: -1.50; 1.22) for body weight, -0.04 mmol/L (95% CI: - 0.09;0.02) for HDL cholesterol, -0.02 mmol/L (95% CI: -0.15; 0.11) for triglycerides and -0.18 mmol/L (95% CI: -0.36; 0.003) for glucose. Most of the studies (66.7%) had concerns of risk of bias. Studies investigating other CVD markers were scarce and with inconsistent findings, where available. Evidence on how BW affects CMH is limited. However, the available literature indicates that BW supplementation in mild dyslipidaemia and type 2 diabetes may provide some benefit in lowering TC and glucose, albeit non-significant. Our work highlights the need for more rigorous trials, with better methodological rigor to clarify remaining uncertainties on potential effects of BW on CMH and its utility in clinical nutrition practice.
-
7.
The Effect of Walnut (Juglans regia) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Mirzababaei, A, Daneshvar, M, Abaj, F, Daneshzad, E, Hosseininasab, D, Clark, CCT, Mirzaei, K
Clinical nutrition research. 2022;11(2):120-132
-
-
-
Free full text
Plain language summary
The main characteristics of type 2 diabetes mellitus (T2DM) are hyperinsulinemia, insulin resistance, and β-cells decline, concomitant to dyslipidaemia. The latter includes abnormalities in concentrations of triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), or total cholesterol (TC), which are major risk factors for cardiovascular diseases. The aim of this study was to evaluate the effect of Juglans regia leaf extract (JRLE) on glycaemic control and lipid profile in T2DM patients. This study is a systematic review and meta-analysis of four randomised controlled studies. All studies were conducted in Iran, on T2DM patients, and both genders. Results show that JRLE supplementation did not have any significant effect on TC, LDL-C, and HDL-C; however, it significantly reduced fasting blood glucose and significantly increased alanine transaminase [enzyme]. Authors conclude that their findings strengthen the available evidence of JRLE as an alternative adjunctive therapy to better control glycaemic targets and lipid parameters.
Abstract
Numerous clinical trials have examined the beneficial effects of Juglans regia leaf extract (JRLE) in patients with type 2 diabetes mellitus (T2DM); however, the results of these studies are inconsistent. Therefore, we conducted the current systematic review and meta-analysis to evaluate the effect of JRLE on glycemic control and lipid profile in T2DM patients. We searched online databases including PubMed, Scopus, EMBASE, and Web of Science for randomized controlled clinical trials that examined the effect of JRLE on glycemic and lipid indices in T2DM patients. Data were pooled using both fixed and random-effect models and weighted mean difference (WMD) was considered as the overall effect size. Of the total records, 4 eligible studies, with a total sample size of 195 subjects, were included. The meta-analysis revealed that JRLE supplementation significantly reduces fasting blood glucose (WMD, -18.04; 95% confidence interval [CI], -32.88 mg/dL, -3.21 mg/dL; p = 0.017) and significantly increases fasting insulin level (WMD, 1.93; 95% CI, 0.40 U/L, 3.45 U/L; p = 0.014). Although the overall effect of JRLE supplementation on hemoglobin A1c was not significant, a significant reduction was seen in studies with an intervention duration of > 8 weeks (WMD, -0.64; 95% CI, -1.16%, -0.11%; p = 0.018). Moreover, we also found no significant change in lipid parameters. Our findings revealed a beneficial effect of JRLE supplementation on glycemic indices in T2DM patients, but no significant improvement was found for lipid profile parameters.
-
8.
Effects of the Treatment with Flavonoids on Metabolic Syndrome Components in Humans: A Systematic Review Focusing on Mechanisms of Action.
Gouveia, HJCB, Urquiza-Martínez, MV, Manhães-de-Castro, R, Costa-de-Santana, BJR, Villarreal, JP, Mercado-Camargo, R, Torner, L, de Souza Aquino, J, Toscano, AE, Guzmán-Quevedo, O
International journal of molecular sciences. 2022;23(15)
-
-
-
Free full text
Plain language summary
Metabolic syndrome is a condition characterised by at least three of the five risk factors, such as abdominal obesity, elevated fasting glucose, blood pressure and triglycerides and reduced high-density lipoprotein cholesterol (HDL-c). There is a strong link between metabolic syndrome and the development of cardiovascular disease and Type 2 diabetes. Research suggests that increasing consumption of flavonoid-rich foods can be beneficial in reducing cardiovascular morbidity and mortality. Flavonoids are bioactive compounds that possess antioxidative, anti-inflammatory, anti-cancerous, anti-mutagenic, and enzymatic properties. This systematic review of 29 randomised controlled trials evaluated the beneficial effects of long-term flavonoid supplementation in reducing the risk factors of metabolic syndrome. This review included a variety of flavonoid supplements, such as anthocyanin, hesperidin, quercetin, epigallocatechin gallate (egcg), genistein, theaflavin, catechin, and eriocitrin. Additionally, this research investigated the mechanisms behind the beneficial effects of flavonoid supplementation. Results showed that flavonoid supplementation for at least three weeks improved metabolic parameters and inflammatory markers, with hesperidin showing the greatest improvements in metabolic parameters. Healthcare professionals can use these findings to understand the potential benefits of long-term flavonoid supplementation in improving metabolic parameters. However, more robust studies are needed to determine the therapeutic dosages of different flavonoids.
Abstract
Diets high in bioactive compounds, such as polyphenols, have been used to mitigate metabolic syndrome (MetS). Polyphenols are a large group of naturally occurring bioactive compounds, classified into two main classes: non-flavonoids and flavonoids. Flavonoids are distributed in foods, such as fruits, vegetables, tea, red wine, and cocoa. Studies have already demonstrated the benefits of flavonoids on the cardiovascular and nervous systems, as well as cancer cells. The present review summarizes the results of clinical studies that evaluated the effects of flavonoids on the components of the MetS and associated complications when offered as supplements over the long term. The results show that flavonoids can significantly modulate several metabolic parameters, such as lipid profile, blood pressure, and blood glucose. Only theaflavin and catechin were unable to affect metabolic parameters. Moreover, only body weight and body mass index were unaltered. Thus, the evidence presented in this systematic review offers bases in support of a flavonoid supplementation, held for at least 3 weeks, as a strategy to improve several metabolic parameters and, consequently, reduce the risk of diseases associated with MetS. This fact becomes stronger due to the rare side effects reported with flavonoids.
-
9.
Fruit and vegetable consumption and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective studies.
Halvorsen, RE, Elvestad, M, Molin, M, Aune, D
BMJ nutrition, prevention & health. 2021;4(2):519-531
-
-
-
Free full text
Plain language summary
Type 2 diabetes is a growing health concern worldwide, with projections estimating it will affect over 700 million people by 2045. Studies have indicated a link between increased consumption of fruits and vegetables and decreased risk of Type 2 diabetes. This systematic review and meta-analysis of twenty-three prospective cohort studies explored this link further, examining the effects of different types of fruits and vegetables on the risk of Type 2 diabetes. The results suggest that a high intake of combined fruits and vegetables and specific varieties, such as apples, pears, blueberries, grapes, and raisins, may slightly reduce the risk of developing Type 2 diabetes. However, consuming cantaloupe, fruit drinks, fruit juice, potatoes, Brussels sprouts, and cabbage may increase the risk of developing Type 2 diabetes. The protective effect of fruit and vegetable consumption on the reduction of type 2 diabetes could be attributed to the dietary fibre, antioxidants, vitamins and minerals and phytochemicals present in fruits and vegetables. While further studies are necessary to confirm these results and explore the impact of specific types of fruits and vegetables on Type 2 diabetes risk, healthcare professionals can use this information to promote the protective benefits of including specific subtypes of fruits and vegetables in the diet to reduce the risk of Type 2 diabetes.
Abstract
BACKGROUND The association between intake of fruit and vegetables and their subtypes, and the risk of type 2 diabetes has been investigated in several studies, but the results have been inconsistent. OBJECTIVE We conducted an updated systematic review and dose-response meta-analysis of prospective studies on intakes of fruit and vegetables and fruit and vegetable subtypes and the risk of type 2 diabetes. DESIGN PubMed and Embase databases were searched up to 20 October 2020. Prospective cohort studies of fruit and vegetable consumption and type 2 diabetes mellitus were included. Summary relative risks (RRs) and 95% CIs were estimated using a random effects model. RESULTS We included 23 cohort studies. The summary RR for high versus low intake and per 200 g/day were 0.93 (95% CI: 0.89 to 0.98, I2=0%, n=10 studies) and 0.98 (95% CI: 0.95 to 1.01, I2=37.8%, n=7) for fruit and vegetables combined, 0.93 (95% CI: 0.90 to 0.97, I2=9.3%, n=20) and 0.96 (95% CI: 0.92 to 1.00, I2=68.4%, n=19) for fruits and 0.95 (95% CI: 0.88 to 1.02, I2=60.4%, n=17) and 0.97 (95% CI: 0.94 to 1.01, I2=39.2%, n=16) for vegetables, respectively. Inverse associations were observed for apples, apples and pears, blueberries, grapefruit and grapes and raisins, while positive associations were observed for intakes of cantaloupe, fruit drinks, fruit juice, brussels sprouts, cauliflower and potatoes, however, most of these associations were based on few studies and need further investigation in additional studies. CONCLUSIONS This meta-analysis found a weak inverse association between fruit and vegetable intake and type 2 diabetes risk. There is indication of both inverse and positive associations between intake of several fruit and vegetables subtypes and type 2 diabetes risk, however, further studies are needed before firm conclusions can be made.
-
10.
Effects of Dietary Phytoestrogens on Hormones throughout a Human Lifespan: A Review.
Domínguez-López, I, Yago-Aragón, M, Salas-Huetos, A, Tresserra-Rimbau, A, Hurtado-Barroso, S
Nutrients. 2020;12(8)
-
-
-
Free full text
Plain language summary
Phytoestrogens are polyphenolic molecules with a structural similarity to endogenous human hormones. The main dietary source of these plant secondary metabolites is legumes (particularly soy), and to a lesser extent fruits, vegetables, and cereals. The aim of this study was to synthesize the results obtained by human studies and assess the potential hormone-related health effects of dietary phytoestrogens throughout the human lifespan. Literature shows that: - the impact of phytoestrogens can vary according to the life stage. - soy isoflavones appear not to have any influence on sex and thyroid hormones, bone remodelling and insulin-like growth factor. - although phytoestrogens transfer from maternal blood to the foetus, no effects have been observed in early life. - in later stages of childhood, an increase of androgens and decrease of oestrogens associated with dietary phytoestrogens have been observed in girls and boys, respectively. - in adulthood, endocrine changes arising from phytoestrogen consumption are unclear, although goitrogenic [compounds that interfere with the normal function of the thyroid gland] activity has been observed in men. - in premenopausal women results regarding sex hormones, breast cancer protection and bone remodelling are uncertain. Authors conclude that intake of phytoestrogens does have some physiological effects in humans related to hormone regulation, but like hormones, the benefits depend on the stage of life.
Abstract
Dietary phytoestrogens are bioactive compounds with estrogenic activity. With the growing popularity of plant-based diets, the intake of phytoestrogen-rich legumes (especially soy) and legume-derived foods has increased. Evidence from preclinical studies suggests these compounds may have an effect on hormones and health, although the results of human trials are unclear. The effects of dietary phytoestrogens depend on the exposure (phytoestrogen type, matrix, concentration, and bioavailability), ethnicity, hormone levels (related to age, sex, and physiological condition), and health status of the consumer. In this review, we have summarized the results of human studies on dietary phytoestrogens with the aim of assessing the possible hormone-dependent outcomes and health effects of their consumption throughout a lifespan, focusing on pregnancy, childhood, adulthood, and the premenopausal and postmenopausal stages. In pregnant women, an improvement of insulin metabolism has been reported in only one study. Sex hormone alterations have been found in the late stages of childhood, and goitrogenic effects in children with hypothyroidism. In premenopausal and postmenopausal women, the reported impacts on hormones are inconsistent, although beneficial goitrogenic effects and improved glycemic control and cardiovascular risk markers have been described in postmenopausal individuals. In adult men, different authors report goitrogenic effects and a reduction of insulin in non-alcoholic fatty liver patients. Further carefully designed studies are warranted to better elucidate the impact of phytoestrogen consumption on the endocrine system at different life stages.