Selenium supplementation in chronic kidney disease patients undergoing haemodialysis: a systematic review of the effects on plasma selenium, antioxidant and inflammatory markers, immunological parameters and thyroid hormones.

Selenium (Se) is a mineral with several biological functions, and studies have shown that its deficiency can be linked to many complications in patients with chronic kidney disease (CKD). This study aims to systematically review the effects of Se supplementation in patients with CKD undergoing haemodialysis (HD). This systematic review was carried out according to the PRISMA statement. Clinical trials were searched in PubMed, Lilacs, Embase, Scopus and Cochrane Library databases from inception to July 2021 and updated in July 2024. The protocol was registered on PROSPERO (CRD42021231444). Two independent reviewers performed the study screening and data extraction, and the risk of bias was evaluated using the Cochrane Collaboration tool. Thirteen studies were included in this review. Only nine studies showed results on Se levels; in all, reduced Se levels were observed before supplementation. A positive effect of supplementation on plasma Se level was demonstrated. Of the ten studies analysed, six demonstrated positive effects on antioxidant and inflammatory markers. Only one study analysed immunological parameters, showing a positive impact. From two studies that analysed thyroid hormones, only one showed positive results. All studies were classified as high risk of bias. The findings suggest that Se supplementation significantly increases plasma Se levels in these patients; however, there are still not enough studies to clarify the effects of Se supplementation on the antioxidant and inflammatory markers, immune system and thyroid hormones. Further studies are needed to elucidate the effects of Se supplementation and to provide a recommendation for patients with CKD undergoing HD.

The magical smell and taste: Can coffee be good to patients with cardiometabolic disease?

Coffee is a beverage consumed globally. Although few studies have indicated adverse effects, it is typically a beneficial health-promoting agent in a range of diseases, including depression, diabetes, cardiovascular disease, and obesity. Coffee is rich in caffeine, antioxidants, and phenolic compounds, which can modulate the composition of the gut microbiota and mitigate both inflammation and oxidative stress, common features of the burden of lifestyle diseases. This review will discuss the possible benefits of coffee on complications present in patients with diabetes, cardiovascular disease and chronic kidney disease, outwith the social and emotional benefits attributed to caffeine consumption.

Can Resveratrol Supplementation Reduce Uremic Toxin Plasma Levels From the Gut Microbiota in Nondialyzed Patients With Chronic Kidney Disease?

OBJECTIVES: Uremic toxins such as indoxyl sulfate (IS), p-cresyl sulfate (pCS), and indole-3-acetic acid (IAA) produced by the gut microbiota are recognized as risk factors for many comorbidities, including cardiovascular diseases. Patients with chronic kidney disease (CKD) have an accumulation of these toxins, and nutritional strategies have been proposed to mitigate gut dysbiosis and, consequently, reduce these toxins. This study aimed to evaluate the effects of resveratrol supplementation on the plasma levels of IS, pCS, and IAA in nondialyzed patients with CKD. METHODS: In this placebo-controlled crossover study, twenty nondialyzed patients were randomly divided into two groups: they received either one capsule/day containing 500 mg of trans-resveratrol (63 ± 7.5 years, glomerular filtration rate [GFR]: 34 ± 14 mL/min, body mass index: 26.8 ± 5.6 kg/m2) or a placebo containing 500 mg wheat flour (62 ± 8.4 years, GFR: 34 ± 13 mL/min, body mass index: 28.6 ± 4.4 kg/m2) during 4 weeks. After 8 weeks of washout (no supplementation), another 4 weeks of supplementation with crossover was initiated. IS, IAA, and pCS plasma levels were quantified by the reverse phase high-efficiency liquid chromatography method with fluorescent detection. The mRNA expression of nuclear factor erythroid 2-related factor 2 and nuclear factor kappa B in peripheral blood mononuclear cells was evaluated by polymerase chain reaction. C-reactive protein plasma levels were also evaluated. RESULTS: As expected, the uremic toxin levels were negatively correlated with the GFR, but no effect of trans-resveratrol supplementation was found on levels of IS, IAA, and pCS. There was a positive correlation between IS and nuclear factor erythroid 2-related factor 2 (r = 0.24, P = .03) and also between IS and C-reactive protein (r = 0.21, P = .05). CONCLUSION: Supplementation with trans-resveratrol did not reduce the plasma levels of IS, pCS, and IAA in nondialyzed patients with CKD. The interactions among uremic toxins and anti-inflammatory and proinflammatory pathways deserve more studies.

Consumption of Fish in Chronic Kidney Disease - A Matter of Depth.

Fish is an excellent source of ω-3 polyunsaturated fatty acids (PUFAs), amino acids, collagen, vitamins, and iodine and its intake is associated with health benefits, mainly reduces risk of cardiovascular mortality. However, recent studies have shown that fish is also an important source of trimethylamine N-oxide (TMAO), a uremic toxin produced by the gut microbiota that promotes an increased risk of cardiovascular diseases. In patients with chronic kidney disease (CKD), TMAO levels are markedly increased due to gut dysbiosis and reduced kidney function. No study has yet evaluated the effects of a fish-rich diet on TMAO plasma levels and cardiovascular outcomes. This review discusses the pros and cons of a fish-rich diet in patients with CKD - a matter of depth.

Nutritional benefits of ginger for patients with non-communicable diseases.

Ginger (Zingiber officinale) is a famous dietary spice rich in bioactive components like gingerols, and it has been used for a long time as food and medicine. Indeed, clinical studies have confirmed the anti-inflammatory and antioxidant properties of ginger. Thus, ginger seems to be an excellent complementary nutritional strategy for non-communicable diseases (NCD) such as obesity, diabetes, cardiovascular disease and chronic kidney disease. This narrative review aims to discuss the possible effects of ginger on the mitigation of common complications such as inflammation, oxidative stress, and gut dysbiosis in NCD.

Effect of cranberry supplementation on toxins produced by the gut microbiota in chronic kidney disease patients: A pilot randomized placebo-controlled trial.

BACKGROUND & AIMS: Patients with Chronic Kidney Disease (CKD) have an imbalance in the gut microbiota that can lead to increase levels of lipopolysaccharides (LPS) and uremic toxins such as indoxyl sulfate (IS), p-cresyl sulfate (p-CS), and indole-3 acetic acid (IAA). Among the therapeutic options for modulating gut microbiota are the bioactive compounds such as polyphenols present in cranberry, fruit with potential antioxidant and anti-inflammatory effects. This clinical trial focuses on evaluating the effects of supplementation with a dry extract of cranberry on plasma levels of LPS and uremic toxins in non-dialysis CKD patients. METHODS: It was a randomized, double-blind, placebo-controlled study. Patients were randomized into two groups: the cranberry group received 500 mg of dry cranberry extract (2 times daily), and the placebo group received 500 mg of corn starch (2 times daily) for two months. LPS plasma levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and uremic toxins (IS, p-CS, and IAA) by high-performance liquid chromatography-fluorescence detection. Anthropometric measurements and food intake using the 24-h food recall technique were also evaluated before and after the intervention. RESULTS: Twenty-five participants completed two months of supplementation: 12 patients in the cranberry group (8 women, 56.7 ± 7.5 years, estimated glomerular filtration rate (eGFR) of 39.2 ± 21.9 mL/min); 13 patients in the placebo group (9 women, 58.8 ± 5.1 years, eGFR of 39.7 ± 12.9 mL/min). As expected, there was a negative association between glomerular filtration rate and p-CS and IS plasma levels at the baseline. No change was observed in the uremic toxins and LPS levels. CONCLUSION: Cranberry dry extract supplementation for two months did not reduce the LPS and uremic toxins plasma levels produced by the gut microbiota in non-dialysis CKD patients.

Resveratrol: why is it a promising therapy for chronic kidney disease patients?

Resveratrol, a phenolic compound found in various plants, including grapes, berries, and peanuts, shows promise for the treatment of cancer, aging, type 2 diabetes, and cardiovascular diseases. Resveratrol can promote transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) activation, increase the expression level of SIRT-1, which is a sirtuin family protein, and reduce mTOR pathway signaling. This compound has anti-inflammatory properties in that it inhibits or antagonizes the nuclear factor-κB (NF-κB) activity, which is a redox-sensitive transcription factor that coordinates the inflammatory response. Inflammation and oxidative stress, which are common features in patients with chronic kidney disease (CKD), are interrelated and associated with cardiovascular disease and the progression of CKD itself. Because of the modulation of the mechanisms involved in the inflammatory-oxidative stress cycle, resveratrol could play an important role in controlling CKD-related metabolic derangements. Although resveratrol supplementation in theory is a promising therapy in this patient group, there are no studies evaluating its effects. Thus, the present review aims to describe the role of resveratrol in inflammation and oxidative stress modulation and its possible benefits to patients with CKD.