The fast spread of the coronavirus disease 2019 (COVID-19) epidemic and its high mortality were quickly noticed by the health community. B vitamins are essential micronutrients for the body with antioxidant, anti-inflammatory and immune-regulating properties. The present study can provide a comprehensive picture of the associations between B vitamins and COVID-19 incidence. This study was undertaken on 9189 adult participants of the Yazd Health Study (YaHS) and Taghzieh Mardom-e-Yazd (TAMIZ) study aged 20 to 69 years. Data on dietary intakes were obtained using a validated FFQ. Multivariable logistic regression analysis was used to evaluate the association between B vitamins and COVID-19. Our findings indicated that participants in the fourth quartile of vitamin B5 intake compared with the first quartile had a protective effect against COVID-19 (OR: 0·53, 95 % CI 0·28, 0·99, P-trend = 0·02) after adjustment for all possible confounds in model 3. In addition, participants in the third quartile of vitamin B12 intake compared with the first quartile (OR: 0·63, 95 % CI 0·40, 0·98, P-trend = 0·11) had fewer odds of COVID-19 after full adjustments for confounders. Our findings indicated no significant relationship between dietary intake of vitamin B1, B2, B3, B9 and B-complex and COVID-19. A higher intake of vitamin B5 could reduce the odds of COVID-19 by 47 %, and a moderate intake of vitamin B12 had a protective effect on COVID-19. Although our study has promising results, stronger clinical studies are needed.

The Mediterranean (MED) diet was associated with a reduced risk of chronic disease, but the epidemiological studies reported inconsistent findings related to the MED diet and non-alcoholic fatty liver disease (NAFLD) risk. This age and the gender-matched case-control study were conducted among 247 adult patients. The MED diet score was obtained based on the Trichopoulou model. Multivariate logistic regression was used to examine the association between the MED diet and NAFLD risk. NAFLD prevalence in people with low, moderate and high adherence to the MED diet was 33, 13⋅1 and 4⋅6 %, respectively. The increasing intake of the MED diet was significantly related to the increment intake of nuts and fruits, vegetables, monounsaturated fatty acid/polyunsaturated fatty acid ratio, legumes, cereals and fish. However, total energy consumption, low-fat dairy and meats intake were reduced (P for all < 0⋅05). Following control for age, the person in the highest of the MED diet tertile compared with the lowest, the odds of NAFLD decreased (OR: 0⋅40, 95 % CI: 0⋅17–0⋅95). This relation became a little stronger after further adjusting for sex, diabetes, physical activity and supplement intake (OR: 0⋅36, 95 % CI: 0⋅15–0⋅89). However, this association disappeared after adjusting for body mass index, waist and hip circumference (OR: 0⋅70, 95 % CI: 0⋅25–1⋅97). High adherence to the MED diet was associated with a 64 % reduction in NAFLD odds before some anthropometric variable adjustments. However, further prospective studies are required, particularly in BMI-stratified models.

Elevated levels of liver enzymes are the main markers of liver dysfunction. Liver enzymes are the important indicators of non-alcoholic fatty liver disease (NAFLD) in the general population. Previous randomised clinical trials (RCT) investigated the effects of Mediterranean diet (MedDiet) as a plant-based diet on features of NAFLD like liver enzymes, but their results are contradictory. This study aimed to systematically review and meta-analyse RCT investigating the effect of MedDiet on liver enzymes. PubMed, Web of Science, Scopus and Google Scholar were searched until December 2020. A total of ten RCT (n 705 participants) evaluating the effect of MedDiet on liver enzymes including aspartate aminotransferase (AST), alanine transaminase (ALT) and γ-glutamyltransferase (GGT) were included. A random effects model was used to estimate the pooled effect size. To evaluate the heterogeneity among the included studies, the Cochran’s Q-test and I-squared test were used. The MedDiet significantly reduced AST (weighted mean difference (WMD) = −0·38 IU/l; 95 % CI − 0·73, −0·03 IU/l; P = 0·03) and GGT (WMD = −0·16 IU/l; 95 % CI − 0·32, −0·006 IU/l; P = 0·04) but had no significant effect on ALT (WMD = −0·55 IU/l; 95 % CI − 1·25, 0·13 IU/l; P = 0·11). However, sensitivity analysis revealed that the overall effects of MedDiet on AST, GGT and ALT were significantly influenced by removing some studies. There was no publication bias based on Begg’s and Egger’s tests. Generally, MedDiet can improve liver enzymes. To better conclusion, further RCT investigating the effect of MedDiet on liver enzymes, especially in patients with NAFLD, are still required.

Although grape polyphenols can decrease chronic inflammations, their effect on C-reactive protein (CRP) levels is still controversial. So, this meta-analysis was conducted to investigate the effect of grape products containing polyphenols on CRP concentrations. In order to collect the relevant randomised controlled trials (RCT), the databases of PubMed, Scopus, Web of Science and Google Scholar were searched up to 30 March 2020. The random effects model, standardised mean difference (SMD) and 95 % CI were applied in data analysis. Meta-analysis was conducted over seventeen eligible RCT containing a total of 668 participants. The study registration number is CRD42018110169. Based on the results, grape products containing polyphenols decreased CRP levels significantly (SMD = −0·229; 95 % CI −0·41, −0·05; P = 0·013). Sensitivity analysis was performed by removing each individual study and the results did not change. According to the subgroup analysis, higher doses of grape polyphenols (>500 mg/d) and longer intervention periods (≥12 weeks) had significant effects on CRP levels. Furthermore, grape polyphenols significantly reduced the CRP levels in patients with a clinical condition. In the same vein, grape seed extract and other grape products, such as grape extract, juice and raisins, decreased CRP levels significantly. According to the meta-regression results, the CRP level depends on the dose and duration of the grape polyphenol supplementation. Based on the findings, grape products containing polyphenols had a significant effect on CRP levels. Further well-designed and long-term clinical trials are highly recommended to achieve more comprehensive and accurate results.

As the results of clinical trials are inconsistent, we conducted this research to assess the effect of purified anthocyanins or anthocyanin-rich extract supplementation on C-reactive protein (CRP) levels. We searched several databases to identify and extract data on characteristics, methods and outcomes of the eligible randomised controlled trials (RCT). A random-effects model, weighted mean difference (WMD) and 95 % CI were applied for data analysis. To investigate the effects of the study quality score or design on our results, we performed the same analysis by excluding the studies of Karlsen et al., with the lowest quality score, and Hassellund et al., with a cross-over design. Meta-analysis showed that anthocyanins had no significant impact on CRP levels (WMD=0·018; 95 % CI –0·44, 0·47; P=0·94). Although the effect of anthocyanins was independent of supplementation duration (slope: 0·01; 95 % CI –0·002, 0·03; P=0·08), their effect depended on the dose of anthocyanins (slope: 0·001; 95 % CI 0·0007, 0·002; P<0·001). However, no significant relationship was found between the anthocyanin dosage and CRP levels after excluding the studies of Karlsen et al. and Hassellund et al. Finally, anthocyanins had no effect on CRP levels regarding healthy participants, patients and types of anthocyanins. Although changes in CRP concentrations had no association with trial duration, a significant relationship was found between anthocyanin dosage and CRP level. No significant result was observed between the anthocyanin dosage and CRP levels after excluding the mentioned studies. Further well-designed RCT are needed to validate these findings.

In this paper, the opacity of plasma in local thermodynamic equilibrium condition was investigated numerically. The plasma was assumed to be produced by interaction of high power pulse laser with carbon and aluminum. Spectrally resolved opacities under different plasma temperature and density conditions were calculated and radiative absorption due to three absorption mechanisms; inverse bremsstrahlung, photo-ionization, and line absorption in plasmas was studied numerically. The purpose of this study is to calculate the values of absorption for inverse bremsstrahlung and photo-ionization processes for aluminum and carbon plasmas and to compare them for those of cold matter. In this investigation, the influences of density and temperature on plasma absorption were evaluated. The calculation results show that the opacity strength strongly depends on the plasma temperature and density.