Current evidence on dietary factors and kidney allograft function in kidney transplant recipients: a systematic review.

BACKGROUND: Currently, there is no accounted-for consensus and practical standard when counseling diet modification for kidney transplant recipients (KTRs). There are many differences between transplant centers regarding what KTRs are needed to follow a diet, what dietary factors and supplements are allowed, and how long KTRs should follow a modified diet. Relatively few scatter data are available for dietary factors in KTRs. Thus, we aimed to systematically review the literature on the purported dietary factors for kidney function. METHODS: A systematic literature search was performed between February and March 2022 and updated in February 2023 using PubMed, Scopus, Web of Science, and Google Scholar. We included human observational and interventional studies that evaluated a dietary factor on kidney function and graft survival in KTRs. Data were extracted, and the risk of bias was assessed using established tools relevant to the study design. RESULTS: Of the 5341 citations retrieved, seven prospective cohorts, five cross-sectional, seventeen randomized, and ten non-randomized clinical trials were included that evaluated seven purported dietary factors. Almost half of the studies (n = 22; 56%) were classified as having a low degree of bias and sufficient support. Twenty-one studies (54%) reported a positive effect on KTRs. DASH and Mediterranean diets decreased graft failure, low-sodium diet reduced blood pressure, and antioxidants improved creatinine, GFR, and graft function. Of these, only twelve studies (31%) were at low risk of bias. CONCLUSION: Some dietary factors, including DASH, Mediterranean, moderate protein, and low-sodium diet, as well as antioxidants, may be associated with improved survival and kidney function in KTRs. However, more research is needed.

Curcumin: A dietary phytochemical for boosting exercise performance and recovery.

Curcumin, as the main natural compound in the turmeric plant (Curcuma longa), is a yellowish polyphenol that has been used traditionally in Asian countries as a medicinal herb for various types of disease and pathological conditions caused by inflammation and oxidative stress. In the present review, we conducted a comprehensive literature search for evidence that shows the effect of curcumin on factors influencing exercise performance, including muscle damage, muscle soreness, inflammation, and oxidative stress. During exercise, reactive oxygen species and inflammation are increased. Thus, if there is no balance between endogenous and exogenous antioxidants and increases in oxidative stress and inflammation, which is important for maintaining redox homeostasis in skeletal muscle, it can lead to muscle soreness and muscle damage and ultimately result in reduced exercise performance. Due to the anti-oxidant and anti-inflammatory properties of curcumin, it can increase exercise performance and decrease exercise-induced muscle soreness and muscle damage. It appears that curcumin supplementation can have positive effects on exercise performance and recovery, muscle damage and pain, inflammation, and oxidative stress. However, there is still a need to precisely evaluate factors to more accurately assess/quantify the beneficial therapeutic effects of curcumin with regard to enhancing exercise performance and recovery.

Evaluation of non-invasive arterial stiffness parameters and their relationship with physical activity, anthropometric indices and lipid profiles in healthy middle-aged adults: Results of the PERSIAN cohort study.

BACKGROUND: Arterial stiffness (AS) indicates the initial stage of cardiovascular disease (CVD), which is associated with modifiable and lifestyle risk factors. We aimed to examine the association of AS with anthropometric indices, lipid profiles and physical activity (PA). METHODS: Six hundred and fifty-eight healthy middle-aged adults were selected and anthropometric indices [body mass index, waist circumferences (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), neck circumferences, a body shape index (ABSI), body roundness index (BRI), body fat mass (BFM), visceral fat area, fat-free mass (FFM), lipid profiles and PA] were measured. AS is measured by carotid-femoral pulse wave velocity (cf-PWV) and central augmentation index (cAIx). RESULTS: Our results show that cf-PWV was positively associated with TGs (ß = 0.10, P = .01) and anthropometric indices correlated with WC (ß = 0.11, P = .02), WHR (ß = 0.09, P = .03), WHtR (ß = 0.1, P = .02) and BRI (ß = 0.09, P = .04). cAIx was independently positively associated with cholesterol (ß = 0.08, P = .03), WC (ß = 0.1, P = .03), WHR (ß = 0.09, P = .02), ABSI (ß = 0.09, P = .01), BRI (ß = 0.08, P = .05), visceral fat area (ß = 0.09, P = .03) and BFM (ß = 0.08, P = .04) and negatively associated with PA (ß = -0.08, P = .03). CONCLUSIONS: WC, WHR and BRI were associated with both cf-PWV and cAIx. TGs and WHtR were associated with cf-PWV, while cAIx was associated with ABSI, improving these indices may be helpful to prevent CVD.

Impact of curcumin on fatty acid metabolism.

Free fatty acids (FFAs) and fatty acid synthesis (FAS) activity have significantly contributed to disease states such as insulin resistance, obesity, type 2 diabetes, myocardial infarction, blood pressure, and several types of cancer. Currently, several treatment options are available for patients with these conditions. Due to safety concerns, adverse effects, limited efficacy, and low tolerability associated with many medications, the identification of novel agents with less toxicity and a more favorable outcome is warranted. Curcumin is a phenolic compound derived from the turmeric plant with various biological activities, including anticarcinogenic, antioxidant, antiinflammatory, and hypolipidemic properties. PubMed, Scopus, and Web of Science were searched up to February 2020 for studies that demonstrated the efficacy and mechanisms of curcumin action on FFAs, FAS, and ß-oxidation activity, as well as the desaturation system. Most of the evidence is in-vivo and in-vitro studies that demonstrate that curcumin possesses regulatory properties on FFAs levels through its effects on FAS and ß-oxidation activity as well as desaturation system, which could improve insulin resistance, obesity, and other FFAs-related disorders. The present study provides a review of the existing in-vitro, in-vivo, and clinical evidence on the effect of curcumin on FFAs and FAS activity, ß-oxidation, and desaturation system.

Does Dietary Intake Impact Omentin Gene Expression and Plasma Concentration? A Systematic Review.

BACKGROUND: Omentin is an adipokine with anti-inflammatory and insulin-sensitizing effects that can play a protective role against cardiovascular disease and diabetes. The aim was to systematically review and summarize the existing evidence on the association between overall dietary intake and omentin gene expression and circulation. SUMMARY: A literature search was conducted in PubMed, Scopus, and Web of Science up to September 2019. Of the 1,940 retrieved articles, 20 relevant studies were included, 6 of which were observational, 11 were clinical trials in humans, and 3 were animal studies. Four randomized controlled trials (RCTs) had a high risk of bias (RoB), 1 had "some concerns", and 2 had a low RoB. Among the nonrandomized studies with comparators, 4 had a serious RoB and 2 had a moderate RoB. In the experimental animal studies with a moderate RoB, conflicting results for omentin serum concentration were found for high-fat and low-fat diets. A high-fat diet (HFD) was shown to reduce omentin gene expression in one animal study. In the observational studies, omentin serum concentration was reduced by Ramadan fasting and saturated fatty acid (SFA) intake, and an increase in omentin gene expression was observed with monounsaturated fatty acid (MUFA) intake. There was no association of dietary inflammatory index (DII), macronutrient intake, or total calorie intake with omentin plasma concentrations. In the human interventional studies, omentin plasma concentration increased with a long-term low-calorie, low-fat diet (LFD), and no change was seen with a HFD or a short-term low-calorie diet (LCD). Key Messages: It seems that a long-term diet with a lower fat content and a balanced distribution of fatty acids, i.e., a higher MUFA and lower SFA intake, may effectively increase omentin plasma concentration, possibly via improved insulin resistance and reduced inflammation, but more research is needed to confirm or refute this.

Association of plasma fatty acids pattern with omentin gene expression in human adipose tissues: A cross-sectional study.

BACKGROUND AND AIMS: Omentin, as an adipokine, has been reported to improve insulin resistance and inflammation may be related to fatty acids (FAs). Plasma FAs can be used as biomarkers of dietary FAs and endogenous FA exposure. We aimed to evaluate the association between plasma FAs pattern and omentin gene expression in adipose tissue (AT). METHODS AND RESULTS: Visceral and subcutaneous AT and fasting blood were gathered from 97 adults aged >18 years. Participants were already admitted to hospitals for elective abdominal surgery. Dietary intakes were assessed using a food frequency questionnaire. The relative omentin gene expression in visceral and subcutaneous AT was measured by Real-Time PCR and plasma FAs was determined by gas chromatography. The principal component analysis was performed to derive the FAs pattern from plasma individual FAs. Three patterns were derived from plasma FAs, 1) high de-novo lipogenesis (DNL), 2) high trans saturated fatty acids (SFA), and docosahexaenoic acid (trans-SFA/DHA), and 3) high long-chain SFA (LC-SFA). After adjustment for age, sex, and insulin concentration, only the LC-SFA pattern was associated with omentin gene expression in visceral AT (ß = 2.25, P = 0.03). Other patterns were not associated with omentin gene expression in visceral and subcutaneous AT. CONCLUSION: A pattern characterized by high levels of myristic acid (14:0), heptadecanoic acid (17:0), pentadecanoic acid (15:0), and Cis_heptadecanoic acid (17:1), which named LC-SFA was related to omentin gene expression in visceral AT.

Associations of dairy intake with risk of incident metabolic syndrome in children and adolescents: Tehran Lipid and Glucose Study.

AIMS: This cohort study examined the association of total and individual dairy products with the risk of incident MetS and its components in children and adolescents. METHODS: We prospectively assessed 531 participants aged 6-18 years without the MetS at baseline during an average 6.6-year follow-up period. Dairy consumption was estimated with a valid and reliable food frequency questionnaire. The MetS was defined according to the Cook criteria. The multivariable regression model was used to calculate the odds ratio (OR) for incident MetS associated with the consumption of dairy products. RESULTS: The incidence of MetS was 9.8% after an average 6.6-year follow-up. After adjusting for potential confounders, OR (95% confidence interval) for incident MetS was 0.48 (0.23-1.00) for total dairy, 0.44 (0.21-0.92) for low-fat dairy, 0.46 (0.22-0.98) for low-fat milk, and 0.45 (0.21-0.97) for low-fat yogurt when comparing participants in the highest versus lowest tertile. A moderate intake of regular cheese was associated with decreased risk of MetS (OR = 0.43, 95% CI: 0.19-0.97). Replacing one serving/day of total dairy with nuts was associated with a lower (OR: 0.63, 95% CI: 0.42-0.95), whereas replacement by red and processed meat was associated with higher (OR: 1.55, 95%CI: 1.21-1.97) MetS risk. No significant association was found between high-fat dairy and MetS risk. CONCLUSIONS: Higher consumption of dairy products, particularly low-fat milk and yogurt, was associated with reduced risk of incident MetS, suggesting the capability of low-fat dairy products in the primary prevention of MetS in children and adolescents.