Association of Omnivorous and Vegetarian Diets With Antioxidant Defense Mechanisms in Men

Effects of vegetarian diets on blood lipids, blood glucose, and blood pressure: a systematic review and meta-analysis

High blood lipids, blood glucose, or blood pressure ("3Bs") are established risk factors for cardiovascular diseases. However, the effects of vegetarian diets on these parameters were inconsistent in previous meta-analyses. We conducted a systematic review and meta-analysis with comprehensive subgroup analyses, quality assessment, and sensitivity analyses to confirm the effects of vegetarian diets on 3Bs. The literature was searched from PubMed, Cochrane, and Web of Science databases from the inception to February 2024. Human studies [both observational studies and randomized controlled trials (RCTs)] related to vegetarian diets and reporting 3Bs were included. The subjects were adults; the intervention/exposure was vegetarian diet which excludes the consumption of any meat, fish, and seafood and the control was an omnivorous diet; the minimum study length was two weeks. The results showed that the vegetarian diets significantly reduced the blood total cholesterol [WMD: -0.54 (95% CI: -0.60, -0.48) mmol L-1, p < 0.001 for observational studies; WMD: -0.24 (95% CI -0.37, -0.10) mmol L-1, p < 0.001 for RCTs], low-density lipoprotein cholesterol [WMD: -0.41 (95% CI: -0.48, -0.34) mmol L-1, p < 0.001 for observational studies; WMD: -0.25 (95% CI: -0.38, -0.12) mmol L-1, p < 0.001 for RCTs], and high-density lipoprotein cholesterol [WMD: -0.07 (95% CI: -0.09, -0.05) mmol L-1, p < 0.001 for observational studies; WMD: -0.07 (95% CI: -0.11, -0.04) mmol L-1, p < 0.001 for RCTs] level compared with the omnivorous diet in both healthy subjects and subjects with chronic diseases, while it had a null effect on the blood triglyceride level. In addition, the vegetarian diets significantly reduced the fasting blood glucose (FBG) [WMD: -0.35 (95% CI: -0.50, -0.21) mmol L-1, p < 0.001], glycated hemoglobin [WMD: -0.15 (95% CI: -0.28, -0.01) %, p = 0.034], and HOMA-IR [WMD: -0.98 (95% CI: -1.46, -0.51), p < 0.001] compared with the omnivorous diet, particularly when the duration was more than 12 weeks. The reduction effect on FBG was particularly significant by a vegan diet and/or in subjects with chronic diseases. The effects of the vegetarian and omnivorous diets on systolic and diastolic blood pressure were not significantly different.

Dietary Antioxidants and Natural Compounds in Preventing Thrombosis and Cardiovascular Disease

Reactive oxygen species (ROS) contribute to endothelial dysfunction, platelet activation, and coagulation abnormalities, promoting thrombus formation. Given the growing interest in non-pharmacological approaches to modulate oxidative stress, we examine the potential of various dietary interventions and antioxidant supplementation in reducing oxidative damage and preventing thrombotic events. Key dietary patterns, such as the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and ketogenic diets, as well as antioxidant-rich supplements like curcumin, selenium, and polyphenols, demonstrate promising effects in improving oxidative stress markers, lipid profiles, and inflammatory responses. This review highlights recent advances in the field, drawing from in vitro, ex vivo, and clinical studies, and underscores the importance of integrating dietary strategies into preventive and therapeutic approaches for managing thrombosis and cardiovascular health. Further research is needed to better understand long-term effects and personalize these interventions for optimizing patient outcomes.

The potential impact of a vegetarian diet on glaucoma

Treatment of primary open-angle glaucoma has centered on the lowering of intraocular pressure that damages the optic nerve; however, this strategy is not uniformly successful, especially in normal tension glaucoma, and there is interest in antioxidant, anti-inflammatory, and other neuroprotective strategies. Vegetarian diets are known to be rich in antioxidant and anti-inflammatory components and have a number of established health benefits. Thus, it would be reasonable to assume that vegetarian diets would be beneficial in glaucoma, but this approach has not been well studied. We examine the possible role of vegetarian diets and their components in the incidence and progression of glaucoma.

Differences in carotid to femoral pulse wave velocity and carotid intima media thickness between vegetarian and omnivorous diets in healthy subjects: a systematic review and meta-analysis

Background: Arterial stiffness and atherosclerosis are known risk factors for cardiovascular morbidity and mortality. Vegetarian diets have been associated with cardiovascular benefits, including improvements in metabolic parameters. However, the impact of a vegetarian diet on cardiovascular parameters, specifically arterial stiffness and atherosclerosis, in healthy individuals remains unclear. Thus, this study aims to analyze differences in arterial stiffness and atherosclerosis between vegetarian and omnivorous diets in healthy subjects. Methods: A systematic review and meta-analysis were conducted following established guidelines. PubMed, Scopus, Web of Science, and Cochrane Library databases were searched for studies examining the association between vegetarian and omnivorous diets with arterial stiffness and atherosclerosis. Cross-sectional studies reporting carotid to femoral pulse wave velocity (cf-PWv) as a measure of arterial stiffness and carotid intima media thickness (c-IMT) as a measure of atherosclerosis were included. Data were synthesized using random effects models, and sensitivity analyses, meta-regressions, and assessment of publication bias were performed. Results: Ten studies were included in the systematic review, and seven studies were included in the meta-analysis. The pooled analysis demonstrated that individuals following a vegetarian diet had differences in the levels of arterial stiffness (cf-PWv) compared to those following an omnivorous diet (MD: -0.43 m s-1; 95% CI: -0.63, -0.23). Similarly, atherosclerosis (c-IMT) was found to be different in individuals adhering to a vegetarian dietary pattern (MD = -29.86 mm; 95% CI: -58.41, -1.32). Conclusions: Our findings suggest that a vegetarian diet is associated with improved arterial stiffness and reduced atherosclerosis in healthy individuals. These results support the inclusion of a well-balanced vegetarian dietary pattern in the prevention and management of cardiovascular diseases. However, further research is needed to explore the effects of a vegetarian diet on arterial health in diverse populations and to assess long-term cardiovascular outcomes.

A comprehensive review of healthy effects of vegetarian diets

AIMS

A comprehensive review comparing the effect of vegetarian (V) and non-vegetarian (NV) diets on the major cardiometabolic diseases' outcomes was performed.

DATA SYNTHESIS

We performed literature research (up to December 31, 2022) of the evidence separately for vascular disease (VD), obesity (OB), dyslipidemia (Dysl), hypertension (HPT), type 2 diabetes (T2D), metabolic syndrome (MetS), analyzing only cohort studies and randomized controlled studies (RCTs) and comparing the effect of V and NV diets. Cohort studies showed advantages of V diets compared to NV diets on incidence and/or mortality risk for ischemic heart disease, overweight and OB risk. Most cohort studies showed V had lower risk of HPT and lower blood pressure (BP) than NV and V diets had positive effects on T2D risk or plasma parameters. The few cohort studies on the risk of MetS reported mixed results. In RCTs, V diets, mainly low-fat-vegan ones, led to greater weight loss and improved glycemic control than NV diets and in the only one RCT a partial regression of coronary atherosclerosis. In most RCTs, V diets significantly reduced LDL-C levels (but also decreased HDL-C levels) and BP.

CONCLUSIONS

In this comprehensive review of the association between V diets and cardiometabolic outcomes, we found that following this type of diet may help to prevent most of these diseases. However, the non-uniformity of the studies, due to ethnic, cultural, and methodological differences, does not allow for generalizing the present results and drawing definitive conclusions. Further, well-designed studies are warranted to confirm the consistency of our conclusions.

The impact of a vegetarian diet on chronic kidney disease (CKD) progression - a systematic review

BACKGROUND

A vegetarian diet is a popular alternative to the casual diet - it is considered healthy, and was proven to positively affect cardiovascular health. The Chronic Kidney Disease (CKD) progression is a major issue in the healthcare system, and constitutes a leading cause of death for 1.5% of the global population. The objective of this systematic review was to investigate the potential impact of a vegetarian diet on kidney function in CKD patients.

METHOD

Our systematic review focused on randomized controlled trials (RCTs) which compared the effects of a vegetarian diet (experimental) and a standard omnivore diet (comparator) in terms of the estimated glomerular filtration rate (eGFR) in CKD patients. Inclusion criteria were based on PICO elements, with two researchers involved in browsing the Cochrane and Pubmed search engines. The investigation was performed using the PRISMA 2020 Checklist and PRISMA 2020 flow diagram. The search terms included: 'vegetarian diet' AND 'nephropathy', 'eGFR', 'albuminuria', 'chronic kidney disease'. Bias assessment was performed using RoB 2 tool to determine the validity of the data collected from studies.

RESULTS

Four RCTs with a total of 346 participants were included in the presented systematic review. Two largest RCTs reported an increase in eGFR following a change to a vegetarian diet (p = 0.01 and p = 0.001). Another two found no significant differences between the experimental and control groups, also these trials were associated with a high risk of bias in terms of missing data outcome and the randomization process.

CONCLUSIONS

The findings collected in this systematic review suggest that a vegetarian diet improves renal filtration function in CKD patients. Therefore, it seems essential to conduct further research involving the impact of the diet on the progression of CKD.

Spontaneous Reversal of Vitiligo, a Rare Phenomenon Reported in a Case in Saudi Arabia with an Insight into Metabolic Biochemical Derangements

Background and Objectives: Vitiligo is a skin disorder characterized by hypopigmented macules occurring due to melanocyte destruction. An interplay of several biochemical mechanisms has been proposed to explain the etiopathogenesis of vitiligo, such as genetic, autoimmune responses, generation of inflammatory mediators, oxidative stress, and melanocyte detachment mechanisms. There is no cure for vitiligo; however, pharmacological treatment measures (cosmetic camouflage creams, steroids, psoralen and ultraviolet A (PUVA) therapy, narrowband UVB) are available, but they could have certain side effects. We reported an interesting case of vitiligo in Saudi Arabia that showed reversal of vitiligo, which is an extremely rare phenomenon, with the objective of probing the probable reasons for this reversal. To the best of our knowledge, there is no study on vitiligo that has reported spontaneous reversal of vitiligo in Saudi Arabia so far. Materials and Method: The patient presented to the Family Medicine clinic with a history of restoration of melanin pigment in his lesions after 3 years of the onset of vitiligo. Patients history was taken carefully along with clinical examination, carried out necessary biomedical lab investigations and compiled the data. The data at the time of pigment restoration were compared to the previous data when he developed the lesions. Result: The probable reasons for vitiligo reversal could be markedly decreased psychological stress, regular consumption of an antioxidant-rich herbal drink made of curcumin and honey, and dietary switchover to vegetarianism and an alcohol-free lifestyle. Conclusions: Curcumin-based herbal remedies could be an alternative option to treat vitiligo. These methods must be further explored through clinical trials as they are safer, easily available, and more affordable.

Maternal Adherence to a Dietary Approaches to Stop Hypertension (DASH) Dietary Pattern and the Relationship to Breast Milk Nutrient Content

BACKGROUND

Maternal lifestyle factors, such as diet and nutritional status are likely to affect the composition of breast milk (BM). This study aimed to investigate the association between adherence to a Dietary Approaches to Stop Hypertension (DASH) dietary pattern (DP) and BM nutrient content.

METHOD

A total of 700 milk samples were obtained from 350 lactating women. The dietary intakes of the women in the study were estimated using a validated food frequency questionnaire, which included 65 food items. The total antioxidant activity (TAC) of BM samples was evaluated using the Ferric reducing antioxidant power (FRAP), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), thiobarbituric acid reactive substances (TBARS), and Ellman's assay. Also using commercially available kits, the total protein, calcium, and triglyceride contents in milk were determined.

RESULTS

Individuals in the 3rd tertile of adherence to the DASH diet (highest adherence) consumed more dietary fiber, fruits, vegetables, nuts, legumes, and seeds, low-fat dairy, whole grain, less red and processed meat, sweetened beverages, and sodium than those in the first tertile (lowest adherence). Subjects in the 3rd tertile of DASH DP had higher values of milk DPPH and calcium compared to those in the first tertile (P < 0.05). Milk MDA and triglyceride were significantly lower in the 3rd tertile of DASH diet versus the first tertile (P < 0.05).

CONCLUSION

Our study showed that high adherence to the DASH DP was associated with higher BM DPPH and calcium levels and lower amounts of BM MDA and triglyceride. The adherence to the healthy DPs such as the DASH can improve the quality of BM in lactating women.

Mindfulness-based program to support lifestyle modification and weight loss in infertile women: randomized controlled trial

OBJECTIVE

We evaluated the short-term effects of a mindfulness-based program (MBP) on weight loss through lifestyle modification in infertile women who were overweight or obese.

METHODS

The participants were randomly assigned to 8 consecutive weekly sessions of MBP plus diet or diet alone. Both groups received a customized dietary plan. Body measures were taken and a questionnaire was applied to evaluate dietary habits at baseline and three months later.

RESULTS

The study was completed by 28 women in the MBP group and 24 in the control group. Body weight decreased 1.8 kg (2.1%) in the MBP group (p = 0.001, follow-up vs. baseline) and 1.7 kg (1.9%) in the control group (p = 0.035). There was an average reduction of 2.9 cm of waist circumference in the MBP group (p = 0.008) and 0.3 cm in the control group (p = 0.633). There was a significant reduction in the daily energy intake of the women attending the MBP (mean difference -430 Kcal/day, p=0.010) whereas no significant change was observed in the control group.

CONCLUSION

In the short term, this MBP did not affect weight loss in infertile women, but the MBP intervention contributed to reduce waist circumference, possibly due to a significant decrease in food energy intake.

TRIAL REGISTRATION NUMBER

RBR-7by76r.

Ginsenoside Rb1 Attenuates Triptolide-Induced Cytotoxicity in HL-7702 Cells via the Activation of Keap1/Nrf2/ARE Pathway

Triptolide (TP) is the major bioactive compound extracted from Tripterygium wilfordii Hook F. It exerts anti-inflammatory, antirheumatic, antineoplastic, and neuroprotective effects. However, the severe hepatotoxicity induced by TP limits its clinical application. Ginsenoside Rb1 has been reported to possess potential hepatoprotective effects, but its mechanism has not been fully investigated. This study was aimed at investigating the effect of ginsenoside Rb1 against TP-induced cytotoxicity in HL-7702 cells, as well as the underlying mechanism. The results revealed that ginsenoside Rb1 effectively reversed TP-induced cytotoxicity in HL-7702 cells. Apoptosis induced by TP was suppressed by ginsenoside Rb1 via inhibition of death receptor-mediated apoptotic pathway and mitochondrial-dependent apoptotic pathway. Pretreatment with ginsenoside Rb1 significantly reduced Bax/Bcl-2 ratio and down-regulated the expression of Fas, cleaved poly ADP-ribose polymerase (PARP), cleaved caspase-3, and -9. Furthermore, ginsenoside Rb1 reversed TP-induced cell cycle arrest in HL-7702 cells at S and G2/M phase, via upregulation of the expressions of cyclin-dependent kinase 2 (CDK2), cyclin E, cyclin A, and downregulation of the expressions of p53, p21, and p-p53. Ginsenoside Rb1 increased glutathione (GSH) and superoxide dismutase (SOD) levels, but decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Pretreatment with ginsenoside Rb1 enhanced the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), total Nrf2, NAD(P)H: quinone oxidoreductases-1 (NQO-1), heme oxygenase-1 (HO-1), and Kelch-like ECH-associated protein 1 (Keap1)/Nrf2 complex. Therefore, ginsenoside Rb1 effectively alleviates TP-induced cytotoxicity in HL-7702 cells through activation of the Keap1/Nrf2/ARE antioxidant pathway.

Inflammatory, oxidative and DNA damage status in vegetarians: is the future of human diet green?

The health benefit of a vegetarian diet is still under debate as it may result in a higher intake of some beneficial micronutrients, while others may be reduced, thus influencing various metabolic pathways and health-related biomarkers. This scoping review discusses inflammatory, oxidative and DNA damage status in vegetarians and vegans compared to omnivores. Most of the reviewed studies indicated favorable effects of a vegetarian diet on oxidative status compared to omnivores but did not clearly associate particular dietary habits to genome damage. The evidence on the effect of vegetarian diet on the inflammatory and immunological biomarkers is poor, which could at least partly be explained by methodological constraints such as small sample size, short duration of vegetarianism and inconsistent definitions of the omnivorous diet. The only inflammatory biomarker that seems to be associated with the vegetarian diet was inflammatory mediator C-reactive protein, which in several studies showed lower values in vegetarians as compared to omnivores. There were very few studies on immunological markers and the results on the difference between vegetarians and omnivores were inconclusive. Although several biomarkers involved in oxidative stress and inflammation showed a beneficial association with the vegetarian diet, further research in well-defined and sufficiently sized cohorts is needed to provide more evidence.

Dietary patterns and biomarkers of oxidative stress and inflammation: A systematic review of observational and intervention studies

INTRODUCTION

Oxidative stress and inflammation are known to play a critical role in ageing and chronic disease development and could therefore represent important targets for developing dietary strategies for disease prevention. We aimed to systematically review the results from observational studies and intervention trials published in the last 5 years on the associations between dietary patterns and biomarkers of oxidative stress and inflammation.

METHODS

A systematic search of the PubMed, MEDLINE and Web of Science (January 2015 to October 2020) was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodological quality of selected studies was evaluated based on the NUTRIGRADE and BIOCROSS assessment tools.

RESULTS

In total, 29 studies among which 16 observational studies and 13 intervention studies were found eligible for review. Overall, results indicated an inverse association between plant-based diets - the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diet - and oxidative stress and proinflammatory biomarkers. In observational studies, inverse associations were further revealed for the vegetarian diet, the USDA Healthy Eating Index (HEI) - based diet and the paleolithic diet, whereas a positive association was seen for western and fast food diets. Quality assessment suggested that majority of dietary intervention studies (n = 12) were of low to moderate quality.

CONCLUSIONS

This study provides evidence that the plant-based dietary patterns are associated with lowered levels of oxidative stress and inflammation and may provide valid means for chronic disease prevention. Future large-scale intervention trials using validated biomarkers are warranted to confirm these findings.

Association of Omnivorous and Vegetarian Diets With Antioxidant Defense Mechanisms in Men

Background Evidence that a vegetarian diet rich in antioxidants contributes to cardiovascular health are growing, however, the underlying molecular mechanisms remain unknown. HO-1 (heme-oxygenase-1), a marker of adaptive response, is protective against oxidative stress and has shown cardioprotective effects. Therefore, we evaluated circulating HO-1 levels and the effect of plasma from omnivorous and vegetarians in endothelial cells (human umbilical vein endothelial cells) on modulating NRF2 (nuclear factor erythroid 2-like 2)/HO-1 and nitric oxide production. Methods and Results From 745 participants initially recruited, 44 omnivorous and 44 vegetarian men matched by age and absence of cardiovascular risk factors and diseases were included in this study. Circulating HO-1 was measured using ELISA and human umbilical vein endothelial cells were incubated with plasma from omnivorous and vegetarians. Higher circulating HO-1 concentrations were found in omnivorous compared with vegetarians. Plasma from omnivorous and not from vegetarians induced NRF2/HO-1 and nitric oxide production in human umbilical vein endothelial cells, and increased reactive oxygen species production and caspase activity after incubation with stressor stimulus. Conclusions We suggest that HO-1 induction in omnivorous may indicate a pro-oxidative status since HO-1 is activated under oxidative stress a state not seen in vegetarians.