Tocotrienol-Rich Vitamin E from Palm Oil (Tocovid) and Its Effects in Diabetes and Diabetic Nephropathy: A Pilot Phase II Clinical Trial

The use of vitamin E in ocular health: Bridging omics approaches with Tocopherol and Tocotrienol in the management of glaucoma

Vitamin E, encompassing tocopherols and tocotrienols is celebrated for its powerful antioxidant properties, which help neutralize free radicals and protect cells from oxidative damage. Over the years, research has shown that both tocopherols and tocotrienols offer significant benefits, including protection against radiation damage, cholesterol regulation, cardiovascular health, and neurological disorders. This wide range of benefits highlights the need for further exploration of vitamin E's role in managing various diseases. One particularly promising area is its potential application in treating ocular diseases like glaucoma. Despite advances in treatment, current options have limitations, making the investigation of alternative approaches crucial. Omics technologies, which allow for a detailed examination of biological systems, could provide valuable insights into how tocopherols and tocotrienols work at a molecular level. Their neuroprotective and antioxidative properties make them promising candidates for glaucoma management. Additionally, the sustainability of vitamin E is noteworthy, as by-products from its production can be repurposed into valuable resources for nutraceuticals and pharmaceuticals. As research continues, integrating omics technologies with the study of vitamin E derivatives could unveil new therapeutic possibilities, further enhancing our understanding of its diverse health benefits and its potential role in preventing and managing diseases.

Clinical study on prescription used for invigorating spleen, reinforcing kidney and warming yang combined with calcium dobesilate in treatment of senile diabetic nephropathy

OBJECTIVE

To analyze the clinical effect of prescription used for invigorating spleen, reinforcing kidney and warming yang combined with calcium dobesilate to treat senile diabetic nephropathy (DN).

METHODS

The clinical data of 110 elderly patients with DN in our hospital from November 2020 to November 2021 were selected for retrospective analysis, and they were divided into the observation group (OG, n = 55) and the control group (CG, n = 55) according to the principle of random grouping. The CG received conventional therapy and calcium dobesilate, and the OG received conventional therapy, calcium dobesilate and prescription used for invigorating spleen, reinforcing kidney and warming yang to evaluate the clinical value of different treatment programs by comparing their clinical indicators after treatment.

RESULTS

The total effective rate of clinical treatment in the OG was clearly higher than the CG (P < 0.05). The blood glucose indexes, and the levels of ALB and RBP in the OG were visibly lower than the CG after treatment (P < 0.001). After treatment, the average levels of BUN and Cr in the OG were visibly lower than the CG (P < 0.001), while the average eGFR level was significantly higher than the CG (P < 0.001).

CONCLUSION

The prescription used for invigorating spleen, reinforcing kidney and warming yang combined with calcium dobesilate is a reliable method to improve the hemorheology indexes and renal function of DN patients, which benefits patients, and further studies are helpful to establish a better solution for such patients.

Single and mixed associations of composite antioxidant diet on triglyceride-glucose index

BACKGROUND

Although the relationship between oxidative stress and insulin resistance (IR) has been established, the associations of the composite dietary antioxidant index (CDAI) and its components with the surrogate index of insulin resistance (IR), triglyceride-glucose index (TyG), is still not clear.

METHODS

This study analyzed the cross-sectional data of the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. Multivariate linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to analyze the associations of the CDAI and its components with the TyG. In addition, subgroup analysis and several sensitivity analyses were conducted.

RESULTS

A total of 14,673 participants with complete data were included, with a median age of 50 years and 7,257 women (49%). Multivariate linear regression showed that after full adjustment, the CDAI was significantly negatively associated with the TyG [β: -0.005, 95% CI: (-0.008, -0.002), p = 0.002]. The model in which six nutrients were mutually corrected showed that vitamin E (per-SD increase) was most strongly associated with the TyG [β: -0.062, 95% CI: (-0.074, -0.050), p < 0.0001]. In the WQS model, the WQS index of the antioxidant diet was negatively associated with the TyG (β: -0.060; P < 0.0001). Similar effects were observed in the BKMR analysis. Notably, in the WQS and BKMR models, vitamin E became the most influential component. In addition, in the subgroup analysis, the association between the CDAI and the TyG in overweight or obese and diabetic populations was significantly weaker.

CONCLUSION

Antioxidant diets, especially vitamin E, are significantly negatively correlated with TyG. This study emphasizes the important value of supplementing vitamin E to improve IR. However, patients with poor weight management and diabetes seem to benefit less from antioxidant diets.

Increased calcium intake from skimmed milk in energy-restricted diets reduces glycation markers in adults with type 2 diabetes and overweight: A secondary analysis of a randomized clinical trial

The effect of calcium (Ca) on glycation markers is unknown. We hypothesized that increased Ca intake from skimmed milk associated with an energy-restricted diet intake will reduce glycation markers. This reduction will be associated with a greater improvement in markers of metabolic control in adults with type 2 diabetes, overweight, and low habitual Ca intake (<600 mg/d). In this secondary data analysis based on a crossover clinical trial, 14 adults were allocated into 2 groups: high calcium (shake containing 700 mg Ca/day) or low calcium (shake with 6.4 mg Ca/day), for 12 consecutive weeks per session. Energy-restricted diets were also prescribed (-500 kcal/d, 800 mg of dietary Ca/d) to all participants. Advanced glycation end products (AGEs), soluble receptor for AGEs (sRAGE), glycemic control, and lipid profile were assessed at baseline and after 12 weeks. High-calcium serum AGE concentrations and AGE/sRAGE ratio were lower at the end of the study. ΔAGE and ΔAGE/sRAGE ratio were both positively associated with Δtriglycerides, Δtotal cholesterol, Δtriglyceride-glucose index and variations, and Δvisceral adiposity index. ΔAGE/sRAGE was positively associated with Δfructosamine and Δhigh-density lipoprotein-cholesterol, and negatively associated with male sex. Consumption of approximately 1200 mg/day of calcium (3 servings of skim milk) reduced serum AGEs concentrations and the AGE/sRAGE ratio in individuals with diabetes. In general, positive changes in glycation markers are associated with lipid profile, insulin resistance, and adiposity markers worsening. ΔAGEs/ΔsRAGE ratio seems to be a better marker of metabolic status than ΔAGEs and ΔsRAGE alone. Registered in ClinicalTrials.gov (NCT02377076).

Health Benefits of Palm Tocotrienol-Rich Fraction: A Systematic Review of Randomized Controlled Trials

CONTEXT

Vitamin E, a well-known antioxidant with numerous positive effects on human health, encompasses tocotrienol-rich fraction (TRF), a natural variant abundant in palm oil.

OBJECTIVE

This systematic review analyzed findings from randomized controlled trials published until 2022 to evaluate the health impacts of palm TRF.

DATA SOURCES

A literature search was performed in Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, OVID Medline, SCOPUS, and Web of Science from inception until December 2022. Thirty studies involving 2646 patients, including both healthy individuals and those with underlying conditions, were identified.

RESULTS

This review shows palm TRF to be a promising natural supplement against inflammation and lipid peroxidation and that can significantly enhance overall health. Additionally, the study underscores the necessity for further research to ascertain the optimal dosage, formulation, and duration of supplementation, maximizing the potential health advantages.

CONCLUSION

This systematic review provides evidence supporting the health benefits associated with palm TRF.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020204070.

Vitamin E and conflicting understandings in noncommunicable diseases: Is it worth supplementing?

Vitamin E is a lipid-soluble nutrient found mainly in vegetable oils and oilseeds. It is divided into eight homologous compounds; however, only α-tocopherol exhibits vitamin activity. Many advantages are related to these compounds, including cellular protection through antioxidant and anti-inflammatory activity, and improving lipid metabolism. Physiopathology of many diseases incepts with reduced antioxidant defense, characterized by an increased reactive oxygen species production and activation of transcription factors involved in inflammation, such as nuclear factor-kappa B (NF-κB), that can be linked to oxidative stress. Moreover, disorders of lipid metabolism can increase the risk of cardiovascular diseases. In addition, intestinal dysbiosis plays a vital role in developing chronic non-communicable diseases. In this regard, vitamin E can be considered to mitigate those disorders, but data still needs to be more conclusive. This narrative review aims to elucidate the mechanisms of action of vitamin E and if supplementation can be beneficial in a disease scenario regarding non-communicable diseases.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

Effects of Tocotrienol-Rich Fraction Supplementation in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There are a large number of studies that have reported benefits of tocotrienol-rich fraction (TRF) in various populations with different health status. To date, no systematic reviews have examined randomized controlled trials (RCTs) on the effect of TRF supplementations specifically in patients with type 2 diabetes mellitus (T2DM). This systematic review and meta-analysis aim to examine the changes in HbA1c (glycated hemoglobin), blood pressure, and serum Hs-CRP (C-reactive protein high sensitivity) levels at post-TRF supplementation. Online databases including PubMed, Scopus, OVID Medline, and Cochrane Central Register of Controlled Trials were searched from inception until March 2023 for RCTs supplementing TRF in patients with T2DM. A total of 10 studies were included in the meta-analysis to estimate the pooled effect size. The Cochrane Risk-of-Bias (RoB) Assessment Tool was utilized to evaluate the RoB in individual studies. The meta-analysis revealed that TRF supplementation at a dosage of 250-400 mg significantly decreased HbA1c (-0.23, 95% CI: -0.44, -0.02, P < 0.05, n = 754), particularly where the intervention duration is less than 6 mo (-0.47%, 95% CI: -0.90, -0.05, P < 0.05, n = 126) and where duration of diabetes is less than 10 y (-0.37, 95% CI: -0.68, -0.07, P < 0.05, n = 83). There was no significant reduction in systolic and diastolic blood pressure and serum Hs-CRP (P > 0.05). The present meta-analysis demonstrated that supplementing with TRF in patients with T2DM decreased HbA1c but does not decrease systolic and diastolic blood pressure and serum Hs-CRP.

Safety and efficacy of oil palm phenolic supplementation in improving lipid profile among hyperlipidemic adults: a phase 2, randomized, double-blind, placebo-controlled clinical trial

Introduction: Oil palm phenolic (OPP) is an antioxidant aqueous palm oil by-product and contains a high amount of phenolics. OPP has been proven to have many therapeutical benefits, and one of them is as an antihyperlipidemic agent. The previous phase 1 clinical trial proved OPP was safe to be orally consumed by healthy volunteers and yielded a good lipid profile. Thus, this phase 2 clinical trial was conducted to determine the effectiveness of OPP in improving the lipid profile among hyperlipidemic subjects. Methods: A parallel, placebo-controlled, randomized, double-blinded clinical trial was conducted for 2 months on 50 hyperlipidemic subjects aged 20-50 years old. The subjects were randomly distributed to two treatment arms with 25 participants each: control/placebo (11 males and 14 females) and 250 mg of OPP (10 males and 15 females). The subjects were required to consume one capsule per day for 60 days. Fasting blood sampling for routine blood profile (hematology, liver function, renal function, and lipid) analysis and a medical examination were conducted at baseline, day 30, and day 60. t-test analysis was used to compare the difference between two test groups. Results: The baseline lipid profile between control group (TC, 5.78 ± 0.52 mmol/L; LDL, 3.88 ± 0.51 mmol/L; HDL, 1.30 ± 0.25; TG, 1.30 ± 0.82), and 250 mg OPP (TC, 5.76 ± 0.54 mmol/L; LDL, 3.82 ± 0.59 mmol/L; HDL, 1.37 ± 0.34; TG, 1.25 ± 0.54) is insignificant. No serious adverse events (SAEs) were reported. No abnormality in fasting blood parameters in all groups was found. Compared to the control group among male participants, the 250 mg OPP group showed an improved serum triglyceride level. There were no statistically significant changes in all blood parameters from day 1 to day 60 with the exception of triglyceride level. Conclusion: The absence of SAEs reported and no abnormal findings in biochemistry and hematology results suggested that the 250 mg OPP was safe to be taken by hyperlipidemic patients with a high probability of reducing triglyceride level in hyperlipidemic male patients The outcomes from this phase II trial suggest that by incorporating OPP supplements into the diet may be a promising strategy for individuals with hyperlipidemia to improve their lipid profiles and reduce cardiovascular risk. However, more research is needed to fully understand the mechanisms of action and establish the long-term efficacy and safety of OPP supplementation in larger scale. Limitation: Small samples size hence lack of diversity (25 subjects per groups) and early sharing of treatment-response results. Clinical Trial Registration: clinicaltrials.gov, identifier NCT04573218.

Effect of vitamin E intake on glycemic control and insulin resistance in diabetic patients: an updated systematic review and meta-analysis of randomized controlled trials

Since a 2014 meta-analysis, several randomized controlled trials (RCTs) evaluating the effect of vitamin E intake on glycemic indices and insulin resistance in adults with diabetes have reached inconsistent conclusions. Therefore, we updated the previous meta-analysis to summarize the current evidence in this regard. Online databases including PubMed, Scopus, ISI Web of Science, and Google Scholar were searched to identify relevant studies published up to September 30, 2021, using relevant keywords. Random-effects models were used to obtain overall mean difference (MD) comparing vitamin E intake with a control group. In total, 38 RCTs with a total sample size of 2171 diabetic patients (1110 in vitamin E groups and 1061 in control groups) were included. Combining the results from 28 RCTs on fasting blood glucose, 32 RCTs on HbA1c, 13 RCTs on fasting insulin, and 9 studies on homeostatic model assessment for insulin resistance (HOMA-IR) showed a summary MD of -3.35 mg/dL (95% CI: -8.10 to 1.40, P = 0.16), -0.21% (95% CI: -0.33 to -0.09, P = 0.001), -1.05 µIU/mL (95% CI: -1.53 to -0.58, P < 0.001), and -0.44 (95% CI: -0.82 to -0.05, P = 0.02), respectively. This indicates a significant lowering effect of vitamin E on HbA1c, fasting insulin and HOMA-IR, while no significant effect on fasting blood glucose in diabetic patients. However, in subgroup analyses, we found that vitamin E intake significantly reduced fasting blood glucose in studies with an intervention duration of < 10 weeks. In conclusion, vitamin E intake has a beneficial role in improving HbA1c and insulin resistance in a population with diabetes. Moreover, short-term interventions with vitamin E have resulted in lower fasting blood glucose in these patients. This meta-analysis was registered in PROSPERO with code CRD42022343118.

Diabetes, Ramadan, and driving - Ensuring patient safety while respecting religious autonomy: A qualitative study

BACKGROUND AND AIMS

Hypoglycaemia due to fasting during Ramadan may affect the ability to perform complex activities among people with type 2 diabetes mellitus (T2D), but it is unclear how this affects one's ability to drive. This study aims to explore driving experiences and coping strategies to ensure safe driving among people with T2D who fast during Ramadan.

METHODS

We conducted an exploratory qualitative study and purposefully selected people with T2D who drove and fasted during the past Ramadan period in 2019. In-depth face-to-face interviews were conducted and transcribed verbatim. Data were analysed thematically using a constant comparative method until saturation was achieved (n = 16).

RESULTS

Two major themes were identified, namely: (1) knowing oneself and (2) voluntary self-restriction. Participants described the importance of understanding how Ramadan fasting affected them and their level of alertness. As such, participants often adjusted their daily activities and tested their blood glucose levels to prevent experiencing hypoglycaemia. Other coping strategies reported include adjusting their medications and driving restrictions or driving in the mornings when they were more alert. Findings from this study shed light on participants' experiences and coping mechanisms while driving during Ramadan.

CONCLUSION

Given the risks and effects of hypoglycaemia among those who fast, there is a need to provide appropriate and focused patient education during Ramadan to people with T2D to ensure they can perform complex activities such as driving safely, especially in Muslim majority countries.

The Role of Diacylglycerol Kinase in the Amelioration of Diabetic Nephropathy

The drastic increase in the number of patients with diabetes and its complications is a global issue. Diabetic nephropathy, the leading cause of chronic kidney disease, significantly affects patients’ quality of life and medical expenses. Furthermore, there are limited drugs for treating diabetic nephropathy patients. Impaired lipid signaling, especially abnormal protein kinase C (PKC) activation by de novo-synthesized diacylglycerol (DG) under high blood glucose, is one of the causes of diabetic nephropathy. DG kinase (DGK) is an enzyme that phosphorylates DG and generates phosphatidic acid, i.e., DGK can inhibit PKC activation under diabetic conditions. Indeed, it has been proven that DGK activation ameliorates diabetic nephropathy. In this review, we summarize the involvement of PKC and DGK in diabetic nephropathy as therapeutic targets, and its mechanisms, by referring to our recent study.

The Use of Durum Wheat Oil in the Preparation of Focaccia: Effects on the Oxidative Stability and Physical and Sensorial Properties

Durum wheat oil is an innovative oil that could be considered the “second life” of durum wheat milling by-products. In this study, we proposed the use of this oil in the reformulation of a traditional Italian greased flat bread, namely focaccia, whose typical sensorial features are due to the presence of relevant amounts of oil in its formulation. The chemical, physical, and sensorial features of focaccia with durum wheat oil (DWO) were compared with those of focaccia prepared with olive oil (OO) and sunflower oil (SO). The results showed the prevalence of polyunsaturated fatty acids in DWO, followed by SO. DWO was more resistant to oxidation than SO (induction time 86.2 and 66.3 min, respectively), due to its higher content of tocotrienols (1020 and 70.2 mg/kg in DWO and SO, respectively), but was less resistant than OO, richer in monounsaturated fatty acids, and contained phenolic compounds. The volatile oxidation markers, namely hexanal and nonanal, were less prevalent in OO and DWO than in SO. Texture and color were positively influenced by the use of durum wheat oil, allowing the nutritional improvement of this flat bread in a sustainable and circular manner.

Revisiting the therapeutic potential of tocotrienol

The therapeutic potential of the tocotrienol group stems from its nutraceutical properties as a dietary supplement. It is largely considered to be safe when consumed at low doses for attenuating pathophysiology as shown by animal models, in vitro assays, and ongoing human trials. Medical researchers and the allied sciences have experimented with tocotrienols for many decades, but its therapeutic potential was limited to adjuvant or concurrent treatment regimens. Recent studies have focused on targeted drug delivery by enhancing the bioavailability through carriers, self-sustained emulsions, nanoparticles, and ethosomes. Epigenetic modulation and computer remodeling are other means that will help increase chemosensitivity. This review will focus on the systemic intracellular anti-cancer, antioxidant, and anti-inflammatory mechanisms that are stimulated and/or regulated by tocotrienols while highlighting its potent therapeutic properties in a diverse group of clinical diseases.

Antioxidant for treatment of diabetic complications: A meta-analysis and systematic review

Antioxidants may provide a complementary treatment for patients with chronic diseases. Nevertheless, studies that have measured the effects of antioxidant on diabetes complications have provided conflicting results. This study aimed to elucidate the association between antioxidant and diabetic complications and to develop robust evidence for clinical decisions by systematic reviews and meta-analysis. PubMed, Embase, The Cochrane Library, Web of Science, Scopus databases were searched to collect clinical studies related to the efficacy of antioxidants in the treatment of diabetes complications from inception to May 5, 2021. Statistical meta-analyses were performed using the RevMan 5.4 software. Stata16 software was used to detect publication bias. The data of diabetic nephropathy (DN), diabetic nonalcoholic fatty liver disease (NAFLD), and diabetic periodontitis were collected to analyze the effect of antioxidant on diabetes and the above three complications. The meta-analysis results showed that antioxidant treatment was associated with significantly changes in the fasting plasma glucose (FPG) (standardized mean difference [SMD]: - 0.21 [95% confidence interval [CI]: - 0.33, -0.10], p < 0.001), hemoglobin A1c (HbA1c) (MD: - 0.41 [95% CI: - 0.63, -0.18], p < 0.001), total antioxidant capacity (TAC) (SMD: 0.44 [95% CI: 0.24, 0.63], p < 0.001) and malondialdehyde (MDA) (SMD: - 0.82 [95% CI: - 1.24, -0.41], p < 0.001) than the control group. Antioxidant supplements have the potential to treat three complications of diabetes. In conclusion, the meta-analysis results indicate that antioxidant treatment is effective clinically for diabetes mellitus and its complications.

Impact of Malaysian palm oil on sustainable development goals: co-benefits and trade-offs across mitigation strategies

Palm oil (PO) is an important source of livelihood, but unsustainable practices and widespread consumption may threaten human and planetary health. We reviewed 234 articles and summarized evidence on the impact of PO on health, social and economic aspects, environment, and biodiversity in the Malaysian context, and discuss mitigation strategies based on the sustainable development goals (SDGs). The evidence on health impact of PO is equivocal, with knowledge gaps on whether moderate consumption elevates risk for chronic diseases, but the benefits of phytonutrients (SDG2) and sensory characteristics of PO seem offset by its high proportion of saturated fat (SDG3). While PO contributes to economic growth (SDG9, 12), poverty alleviation (SDG1, 8, 10), enhanced food security (SDG2), alternative energy (SDG9), and long-term employment opportunities (SDG1), human rights issues and inequities attributed to PO production persist (SDG8). Environmental impacts arise through large-scale expansion of monoculture plantations associated with increased greenhouse gas emissions (SDG13), especially from converted carbon-rich peat lands, which can cause forest fires and annual trans-boundary haze; changes in microclimate properties and soil nutrient content (SDG6, 13); increased sedimentation and change of hydrological properties of streams near slopes (SDG6); and increased human wildlife conflicts, increase of invasive species occurrence, and reduced biodiversity (SDG14, 15). Practices such as biological pest control, circular waste management, multi-cropping and certification may mitigate negative impacts on environmental SDGs, without hampering progress of socioeconomic SDGs. While strategies focusing on improving practices within and surrounding plantations offer co-benefits for socioeconomic, environment and biodiversity-related SDGs, several challenges in achieving scalable solutions must be addressed to ensure holistic sustainability of PO in Malaysia for various stakeholders.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11625-021-01052-4.

Tocotrienols-rich naringenin nanoemulgel for the management of diabetic wound: Fabrication, characterization and comparative in vitro evaluations

The present research had been attempted to formulate and characterize tocotrienols-rich naringenin nanoemulgel for topical application in chronic wound conditions associated with diabetes. In due course, different phases of the nanoemulsion were chosen based on the solubility study, where combination of Capryol 90 and tocotrienols, Solutol HS15, and Transcutol P were selected as oil, surfactant, and cosurfactant, respectively. The nanoemulsions were formulated using the spontaneous emulsification method. Subsequently, Carbopols were incorporated to develop corresponding nanoemulgels of the optimized nanoemulsions. Thermodynamically stable optimized nanoemulgels were evaluated for their globule size, polydispersity index (PDI), surface charge, viscosity, mucoadhesive property, spreadability, in vitro release and release mechanism. Further, increasing polymer concentration in the nanoemulgels was reflected with the increased mucoadhesive property with corresponding decrease in the release rate of the drug. The optimized nanoemulgel (NG1) consisted of uniform dispersion (PDI, 0.452 ​± ​0.03) of the nanometric globules (145.58 ​± ​12.5) of the dispersed phase, and negative surface charge (−21.1 ​± ​3.32 ​mV) with viscosity 297,600 ​cP and good spreadability. In vitro release of naringenin in phosphate buffer saline revealed a sustained release profile up to a maximum of 74.62 ​± ​4.54% from the formulated nanoemulgel (NG1) within the time-frame of 24 ​h. Alternatively, the release from the nanoemulsion was much higher (89.17 ​± ​2.87%), which might be due to lack of polymer coating on the dispersed oil droplets. Moreover, the in vitro release kinetics from the nanoemulgel followed the first-order release and Higuchi model with non-Fickian diffusion. Therefore, encouraging results in this research is evident in bringing a promising future in wound management, particularly associated with diabetes complications.

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Thermodynamically stable naringenin-loaded tocotrienol-rich nanoemulgels were fabricated using spontaneous method.

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Developed nanoemulgel possesses nanometric globule size with good spreadability.

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Controlled in vitro release was obtained over a period of 24 ​h.

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First-order release and Higuchi model with non-Fickian diffusion was established in the in vitro release kinetic profile.

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This nanoemulgel could be a promising tool in the management of chronic wound condition.

Scrubbed Palm Fatty Acid Distillate as Vitamin E Concentrate

Vitamin E (VitE) production from crude palm oil (CPO) has been extensively studied and industrially conducted. VitE in CPO is in the range of 600 to 1,000 ppm, and is usually produced from one of the main by-products of edible palm oil production, namely palm fatty acid distillate (PFAD). PFAD contains 4,000 to 5,500 ppm of VitE, and is produced from deodorization process of palm oil purification. This paper presents an innovative process of VitE concentrate production from CPO. A scrubber was designed and installed between the deodorizer and conventional PFAD scrubber. The main objective of this new scrubber was a recovery of glycerides from PFAD. This new scrubber is operated at 150 to 160℃. The scrubbed oil is named as Scrubbed Palm Fatty Acid Distillate (S-PFAD). This simple and efficient modified process can retrieve glycerides as S-PFAD at 0.3% recovery and it enhances VitE concentration in S-PFAD to the range of 28,000 to 32,000 ppm, which is the highest concentration of VitE that has ever been produced in the palm oil production. Fatty acids and glycerides in S-PFAD were esterified and transesterified to methyl esters. The methyl esters were evaporated from S-PFAD, and S-PFAD residue oil contained 24.7% VitE.

A Review of Key Sustainability Issues in Malaysian Palm Oil Industry

The palm oil industry has contributed enormously to the economic growth of developing countries in the tropics, including Malaysia. Despite the industry being a development tool for emerging economies, the oil palm crop is inundated with allegations of its unsustainable plantation practices and viewed as environmentally detrimental and socially adverse. These negative perceptions are amplified through anti-palm oil campaigns and protectionist trade regulations in developed countries, particularly in the European Union (EU). This situation, if further exacerbated, could potentially affect the export of palm oil and the industry as a whole. As such, this article provides a critical review of the key sustainability issues faced by the Malaysian palm oil industry as the second biggest exporter of palm oil to the global market. The various insights and the interpretations of sustainability are contested according to the contexts and the interests of the countries involved. Hence, palm oil is constantly exposed to bias masked by non-tariff barriers from consumer countries to protect their domestically produced vegetable oils. This could constrain the commodity competitiveness in the international market. As issues on palm oil sustainability continue to evolve, policymakers at key stakeholder agencies need to devise strategies to manage global disruption in the palm oil trade.

Effects of tocotrienols supplementation on markers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

Studies investigating the effects of tocotrienols on inflammation and oxidative stress have yielded inconsistent results. This systematic review and meta-analysis aimed to evaluate the effects of tocotrienols supplementation on inflammatory and oxidative stress biomarkers. We searched PubMed, Scopus, and Cochrane Central Register of Controlled Trials from inception until 13 July 2020 to identify randomized controlled trials supplementing tocotrienols and reporting circulating inflammatory or oxidative stress outcomes. Weighted mean difference (WMD) and corresponding 95% confidence interval (CI) were determined by pooling eligible studies. Nineteen studies were included for qualitative analysis, and 13 studies were included for the meta-analyses. A significant reduction in C-reactive protein levels (WMD: −0.52 mg/L, 95% CI: −0.73, −0.32, p < 0.001) following tocotrienols supplementation was observed, but this finding was attributed to a single study using δ-tocotrienols, not mixed tocotrienols. There were no effects on interleukin-6 (WMD: 0.03 pg/mL, 95% CI: −1.51, 1.58, p = 0.966), tumor necrosis factor-alpha (WMD: −0.28 pg/mL, 95% CI: −1.24, 0.68, p = 0.571), and malondialdehyde (WMD: −0.42 μmol/L, 95% CI: −1.05, 0.21, p = 0.189). A subgroup analysis suggested that tocotrienols at 400 mg/day might reduce malondialdehyde levels (WMD: −0.90 μmol/L, 95% CI: −1.20, −0.59, p < 0.001). Future well-designed studies are warranted to confirm the effects of tocotrienols on inflammatory and oxidative stress biomarkers, particularly on different types and dosages of supplementation. PROSPERO registration number: CRD42020198241.

Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt?

Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers' interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.

The effects of tocotrienols intake on obesity, blood pressure, inflammation, liver and glucose biomarkers: a meta-analysis of randomized controlled trials

The objective of this study is to accomplish a systematic review and meta-analysis of all randomized controlled trials that dissected the influence of tocotrienol supplementation on various anthropometric and cardiometabolic indices in all individuals, irrespective of health condition. This research was carried out in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. 17 eligible articles were included in the final quantitative analysis. Current study revealed that tocotrienol consumption was not associated with CRP, WC, MDA, BMI, IL-6, HbA1C, ALT, AST, creatinine TNF-α, FPG, BW, DBP, and SBP. We did observe an overall increase in BW (SMD: 0.063 kg, 95% CI: -0.200, 0.327, p = 0.637) and DBP (SMD: 0.249 mmHg, 95% CI: 0.053, 0.446, p = 0.013). In addition, a significant reduction in SBP was observed (SMD: -0.616 mmHg, 95% CI: -1.123, -0.110, p = 0.017). In summary, our meta-analysis revealed that tocotrienol consumption was associated with increase in BW and DBP and decrease in SBP. Significant associations were not observed for other outcomes.

Effects of delta-tocotrienol supplementation on Glycemic Control, oxidative stress, inflammatory biomarkers and miRNA expression in type 2 diabetes mellitus: A randomized control trial

The study aimed to ascertain the effects of delta-tocotrienol (δT3) supplementation on glycemic control, oxidative stress, inflammation and related micro-ribonucleic acid (miRNA) expression in patients with type 2 diabetes mellitus (T2DM). Total 110 patients of T2DM on oral hypoglycemic agents, were randomly divided into tocotrienol and placebo groups and given 250 mg δT3 or cellulose soft gel capsule once daily respectively for 24 weeks. Glycemic control, oxidative stress, inflammatory biomarkers, and miRNAs expression were measured in serum at baseline and end of the intervention by using standard laboratory methods. Compared to the placebo, δT3 supplementation resulted in a significant (p ≤ .05) reduction [mean difference (95% confidence interval)] in plasma glucose [-0.48 (-0.65, -0.30)], insulin [-1.19 (-1.51, -0.87)], homeostatic model assessment of insulin resistance [-0.67 (-0.86, -0.49)], glycosylated hemoglobin [-0.53 (-0.79, -0.28)], malondialdehyde [-0.34 (-0.45, -0.22)], high sensitive-C-reactive protein[-0.35 (-0.54, -0.16)], tumor necrosis factor-alpha [-1.22 (-1.62, -0.83)], and interleukin-6[-2.30 (-2.91, -1.68)]. More than twofold downregulation in miRNA-375, miRNA-34a, miRNA-21, and upregulation in miRNA-126, miRNA-132 expression was observed in the δT3 group compared to the placebo. The study demonstrated that δT3 supplementation in addition to oral hypoglycemic agents, improved glycemic control, inflammation, oxidative stress, and miRNA expression in T2DM without any adverse effect. Thus, δT3 might be considered as an effective dietary supplement to prevent long-term diabetic complications.

Serum antioxidant vitamin concentrations and oxidative stress markers associated with symptoms and severity of premenstrual syndrome: a prospective cohort study

Background

It has been suggested that premenstrual syndrome (PMS) may derive from either elevated oxidative stress or reduced antioxidant vitamin levels in the body; however, these relationships have been minimally studied in a large cohort of healthy women. Our objective was to estimate the association between serum concentrations of antioxidant vitamins (A, C, and E) and markers of oxidative stress (F2-isoprostane) with symptoms and severity of PMS.

Methods

The BioCycle study was a prospective cohort study following 259 healthy premenopausal women aged 18–44 years for up to 2 menstrual cycles. Frequency/severity of 20 PMS symptoms were assessed via questionnaires 4 times/cycle, and antioxidant vitamins and oxidative stress biomarkers were measured up to 8 times/cycle to correspond with specific cycle phases. Generalized linear models were used to estimate associations between mean antioxidant concentrations and oxidative stress biomarkers with PMS symptoms and severity; linear mixed models were used to evaluate associations with symptom severity scores within groups (e.g. depression, cravings, pain).

Results

Higher concentrations of serum antioxidant vitamins were largely not associated with prevalence or severity of PMS symptoms. Though a few associations were observed, only associations between mean γ-tocopherol and decreased odds of swelling of the hands/feet survived adjustment for multiple comparisons (OR 0.33, 95% CI 0.16, 0.65, per ug/dL). However, F2-isoprostanes were associated with prevalence and severity of several symptoms specifically related to depression and cravings (depression score β = 0.07, 95% CI 0.02, 0.12, per 10 ug/dL; cravings score β = 0.16, 95% CI 0.10, 0.22, per 10 ug/dL), as well as with classification of PMS severity (OR 1.07, 95% CI 1.01, 1.14, per 10 pg/dL), with these associations surviving adjustment for false discovery rate.

Conclusions

F2-isoprostanes, but not antioxidant vitamins, were associated with select PMS symptoms, as well as symptom and severity categories. Specific symptom relationships merit further research.

A Phase IIb Randomized Controlled Trial Investigating the Effects of Tocotrienol-Rich Vitamin E on Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a debilitating complication of diabetes, which develops in 40% of the diabetic population and is responsible for up to 50% of end-stage renal disease (ESRD). Tocotrienols have shown to be a potent antioxidant, anti-inflammatory, and antifibrotic agent in animal and clinical studies. This study evaluated the effects of 400 mg tocotrienol-rich vitamin E supplementation daily on 59 DKD patients over a 12-month period. Patients with stage 3 chronic kidney disease (CKD) or positive urine microalbuminuria (urine to albumin creatinine ratio; UACR > 20–200 mg/mmol) were recruited into a randomized, double-blind, placebo-controlled trial. Patients were randomized into either intervention group (n = 31) which received tocotrienol-rich vitamin E (Tocovid SupraBio^TM; Hovid Berhad, Ipoh, Malaysia) 400 mg daily or a placebo group which received placebo capsules (n = 28) for 12 months. HbA1c, renal parameters (i.e., serum creatinine, eGFR, and UACR), and serum biomarkers were collected at intervals of two months. Tocovid supplementation significantly reduced serum creatinine levels (MD: −4.28 ± 14.92 vs. 9.18 ± 24.96), p = 0.029, and significantly improved eGFR (MD: 1.90 ± 5.76 vs. −3.29 ± 9.24), p = 0.011 after eight months. Subgroup analysis of 37 patients with stage 3 CKD demonstrated persistent renoprotective effects over 12 months; Tocovid improved eGFR (MD: 4.83 ± 6.78 vs. −1.45 ± 9.18), p = 0.022 and serum creatinine (MD: −7.85(20.75) vs. 0.84(26.03), p = 0.042) but not UACR. After six months post washout, there was no improvement in serum creatinine and eGFR. There were no significant changes in the serum biomarkers, TGF-β1 and VEGF-A. Our findings verified the results from the pilot phase study where tocotrienol-rich vitamin E supplementation at two and three months improved kidney function as assessed by serum creatinine and eGFR but not UACR.

Cellular uptake and anti-inflammatory effects of palm oil-derived delta (δ)-tocotrienol in microglia

Tocopherols long dominated studies on vitamin E, although interest has shifted to tocotrienols. It was previously shown that δ-tocotrienol derived from palm oil reduced nitric oxide released by BV2 microglia as early as 18 h after lipopolysaccharide stimulation. The current study measured δ-tocotrienol uptake by BV2 over a 24 h incubation period and its anti-inflammatory effects on primary microglia. Uptake of 17.5 μg/mL δ-tocotrienol by BV2 microglia began as early as 5 min and rose steeply to 21 ± 3% of the amount administered at 24 h. The amount of δ-tocotrienol retained in the lipopolysaccharide-stimulated microglia at 24 h was 14 ± 2%, with no substantial difference seen in unstimulated microglia. The same δ-tocotrienol regimen reduced nitric oxide levels by 82% at 24 h after lipopolysaccharide stimulation (p < 0.05). This was accompanied by decreased inducible nitric oxide synthase protein expression by 67 ± 5% compared to untreated controls (p < 0.05). In primary microglia, δ-tocotrienol downregulated IL-1β production, but TNF-α and IL-6 were not affected. δ-Tocotrienol also reduced prostaglandin E2 production by ~78%% and decreased transcription of COX-2 and 5-LOX, but not COX-1. This study showed the anti-inflammatory effects of δ-tocotrienol derived from palm oil and opens up interest for tocotrienol supplementation to reduce the effects of inflammatory conditions.

The effects of tocotrienol supplementation on lipid profile: A meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE

Tocotrienol supplementation has been emerged as a potent candidate for the treatment of dyslipidemia. In the present study, a systematic review and meta-analysis of randomized controlled trials was performed with the aim of examining the effects of tocotrienol supplementation on the lipid profile.

METHODS

Four databases (Scopus, PubMed/Medline, Web of Science and Embase) were used to accomplish the literature search up to November 2019. Clinical trials encompassing the impact of tocotrienol supplementation on lipid profile were extracted regardless of clinical condition, with studies included involving only adults patients.

RESULTS

A total of 15 articles with 20 arms were eligible and included in the meta-analysis to estimate the pooled effect size. Overall results showed a significant effect of tocotrienol supplementation on increasing high-density lipoprotein cholesterol (HDL-C) levels (weight mean difference (WMD): 0.146 mmol/L, I² = 85.9%) and a non-significant influence on total cholesterol (TC) (WMD: 0.010 mmol/L, I² = 64.5%), low-density lipoprotein cholesterol (LDL-C) (WMD: 0.095 mmol/L, I² = 87.4%), and triglycerides (TG) (WMD: -0.112 mmol/L, I² = 67.4%) levels. Increment in HDL-C levels was significant greater for the tocotrienol dosage ≥ 200 mg/d (WMD: 0.202 mmol/L) and ≤8 weeks (WMD: 0.278 mmol/L). Moreover, studies that investigated tocotrienol dose ≥200 mg had no heterogeneity, while showing a significant decrease in TG levels (WMD: -0.177 mmol/L).

CONCLUSION

The present meta-analysis demonstrated that supplementing with tocotrienols does not decrease the concentrations of LDL-C, TC and TG. However, tocotrienol supplementation was considered a candidate for increasing HDL-C levels.

A Clinical Review on Nutritional Requirements and Assessment for Type 2 Diabetes Mellitus with Chronic Renal Disease

BACKGROUND

A significant correlation exists between type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD), where up to 40% of diabetic patients suffer from CKD as a direct result of diabetic complications. The management of diabetes in CKD patients can be challenging due to their need for disease-specific diets, as well as increased risks of complications due to malnutrition, which is why their dietary needs and nutritional requirements require attention to detail, and have to be assessed and tailored according to the patient's needs.

OBJECTIVES

This systematic review aimed to assess nutritional requirements for type 2 diabetes mellitus patients with chronic renal failure.

METHODS

In this review, 85 articles were screened, and 22 articles were then analyzed and selected as per the study criteria. PRISMA guidelines were used to select and screen the articles. Data search included a PubMed search using MeSH terms, and a literature review through the Cochrane library and the British Medical Journal.

RESULTS

The study highlighted the important nutrients and minerals needed to be maintained within a specified range in accordance with the patient's needs and conditions. In addition, dietary restrictions must be set to prevent disease progression and deterioration. Dietary intake in hemodialysis patients must be carefully calculated based on their needs, with tight monitoring of their blood glucose. Protein intake in hemodialysis patients should be determined based on risk-to-benefit ratios.

CONCLUSION

Dietary requirements should be individualized based on the patient's disease severity and progression. Assessment of the patient's previous and current diet, as well as matching it with their dietary requirements and preferences is crucial.

Tocotrienol-rich vitamin E improves diabetic nephropathy and persists 6-9 months after washout: a phase IIa randomized controlled trial

Chronic hyperglycemia in type 2 diabetes mellitus increases oxidative stress and inflammation which contributes to long-term diabetic kidney disease. Tocotrienol-rich vitamin E, as Tocovid, has been shown to reduce oxidative stress and inflammation to ameliorate diabetes in rat models and human subjects. In this prospective, multicenter, double-blinded, placebo-controlled clinical trial, 54 patients (duration = 18.4 years, HbA1c = 8.8%) with diabetic nephropathy were randomized to receive Tocovid 200 mg or placebo for 12 weeks. Fasting blood samples were taken to measure HbA1c, serum creatinine, estimate glomerular filtration rate (eGFR), urine albumin:creatinine ratio, malondialdehyde, tumor necrosis factor receptor-1, vascular cell adhesion molecule-1 (VCAM-1), and thromboxane-B2. Patients were reassessed 6-9 months post-washout. After 12 weeks of supplementation, Tocovid significantly decreased serum creatinine levels (mean difference: -3.3 ± 12.6 versus 5.4 ± 14.2, p = 0.027) and significantly increase eGFR (mean difference: 1.5 ± 7.6 versus -2.9 ± 8.0, p = 0.045) compared with placebo. There were no significant changes in HbA1c, blood pressure, and other parameters. Subgroup analysis revealed that in patients with low serum vitamin E concentrations at baseline, Tocovid reduced serum creatinine, eGFR, and VCAM-1 significantly. After 6-9 months of washout, persistent difference in serum creatinine remained between groups (mean difference: 0.82 ± 8.33 versus 11.26 ± 15.47, p = 0.031), but not eGFR. Tocovid at 400 mg/day significantly improved renal function in 12 weeks of supplementation, as assessed by serum creatinine and eGFR, which remained significant 6-9 months post-washout.

Serum xanthophyll carotenoids are associated with estimated glomerular filtration rate in an aged cohort

Progressive renal decline is associated with increasing oxidative stress. However, the majority of studies have investigated endogenous antioxidants in predominantly advanced stages of kidney disease. Many traditional risk factors associated with renal dysfunction have been linked with cognitive decline as the kidneys and brain share comparable anatomic and haemodynamic characteristics that leave them susceptible to common pathogenic mechanisms. The objective of this study was to examine serum dietary antioxidants and their association with renal function characterised by estimated glomerular filtration rate (eGFR) in a cross-sectional analysis of 570 participants. High performance liquid chromatography quantified serum levels of retinol, α-tocopherol, γ-tocopherol and six carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene and zeaxanthin) in participants. Multiple regression analyses were used to evaluate associations while adjusting for potential confounders. A sensitivity analysis was performed in cognitively-intact participants only. Serum levels of the xanthophyll carotenoid lutein were positively associated with eGFR in analyses adjusted for age (years), gender, smoking, APOE4 status and Alzheimer’s disease. Retinol was inversely associated with eGFR, although was no longer significant in the smaller sensitivity analysis. Our findings identify significant associations between the xanthophyll carotenoids and eGFR. Further investigations are required to confirm these findings.

Antioxidant, Anti-Inflammatory, and Metabolic Properties of Tocopherols and Tocotrienols: Clinical Implications for Vitamin E Supplementation in Diabetic Kidney Disease

Diabetes mellitus is a metabolic disorder characterized by the development of vascular complications associated with high morbidity and mortality and the consequent relevant costs for the public health systems. Diabetic kidney disease is one of these complications that represent the main cause of end-stage renal disease in Western countries. Hyperglycemia, inflammation, and oxidative stress contribute to its physiopathology, and several investigations have been performed to evaluate the role of antioxidant supplementation as a complementary approach for the prevention and control of diabetes and associated disturbances. Vitamin E compounds, including different types of tocopherols and tocotrienols, have been considered as a treatment to tackle major cardiovascular outcomes in diabetic subjects, but often with conflicting or even negative results. However, their effects on diabetic nephropathy are even less clear, despite several intervention studies that showed the improvement of renal parameters after supplementation in patients with diabetic kidney disease. Then we performed a review of the literature about the role of vitamin E supplementation on diabetic nephropathy, also describing the underlying antioxidant, anti-inflammatory, and metabolic mechanisms to evaluate the possible use of tocopherols and tocotrienols in clinical practice.

The Effect of Antioxidant Vitamins on Patients With Diabetes and Albuminuria: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

This study aimed to investigate the effect of antioxidant vitamins, including vitamins E and C, on patients with diabetes and albuminuria by conducting a meta-analysis of randomized controlled trials.

DESIGN

The PubMed, Embase, CENTRAL (the Cochrane Central Register of Controlled Trials at the Cochrane Library), Web of Science, OVID, and www.clinicaltrials.gov (latest search: December 10, 2018) databases were searched. This study was limited to randomized controlled trials. Patients with diabetes and albuminuria were included regardless of diabetic type, and patients must have received treatment with vitamins C or E.

RESULTS

Ten studies, representing 445 participants, were identified for analysis. Antioxidant vitamins had significant effects on serum creatinine levels (mean difference = -0.11 mg/dL, 95% confidence interval -0.19 to -0.03, P = .007) and systolic pressure (mean difference = -6.02 mm Hg, 95% confidence interval -9.65 to -2.40, P = .001) with low heterogeneity. Antioxidant vitamins had no effect on albuminuria or proteinuria, diastolic blood pressure, glucose, or lipid metabolism.

CONCLUSION

This meta-analysis indicated that antioxidant vitamins can benefit kidney function and systolic blood pressure in patients with diabetes and albuminuria. Further studies with larger sample sizes and longer follow-up are needed to completely understand the effect of antioxidant vitamins in these patients.

Recent advances in the pathogenesis of microvascular complications in diabetes

Millions of people worldwide have diabetes, which is diagnosed by fasting blood glucose levels exceeding 126 mg/dL. Regardless of the type of diabetes, prolonged hyperglycemia is damaging to several organs including eyes, kidneys, nerve, and/or heart. The damages are associated with a high risk of morbidity and mortality. Diabetes has been implicated in ischemia in the microvasculature of the target tissues, which occurs due to the insufficient perfusion of tissues. The resulting occlusion and pain affect the quality of life. Multiple therapeutic approaches have been proposed for a long time to overcome these vascular complications. Apart from systemically controlling high glucose levels, other therapeutic strategies are not well understood. In this review, we summarize the recent literature for biochemical/cellular targets that are being utilized for the treatment of diabetic microvascular diseases. These targets, which are closely associated with mitochondrial dysfunction, include the polyol and diacylglycerol-protein kinase C pathways, oxidative stress, non-enzymatic glycation and the formation of advanced glycation end products, and immune dysregulation/inflammation.