The influence of omega-3 supplementation on vitamin D levels in humans: a systematic review and dose-response meta-analysis of randomized controlled trials

Assessment of performance and egg quality in laying hens of Spanish indigenous breed Black Castellana as compared with a selected white egg-layer strain

Indigenous animal genetic resources should be preserved because of their well adaptation to the environment, their tolerance to low food availability and their sociocultural importance. The characterization of the quality of the products generated by heritage breeds may bring more arguments to encourage the raising of these animals. This study aimed at evaluating the egg performance and quality of Spanish indigenous Black Castellana (BC) breed as compared with a selected strain (Lohmann LSL-Classic). Four groups of 30 hens were arranged: 1) Lohmann hens fed a control diet; 2) BC hens fed the control diet; 3) Lohmann hens fed a diet including linseed at 70 g/kg (omega-3 diet); 4) BC hens fed the omega-3 diet. Egg production was higher by 12.3% for Lohmann hens but, since BC eggs were heavier by 15.4%, no effect of genetics was found on daily egg mass. Feed intake was higher by 5.0% for BC hens. Nonetheless, no difference was detected for feed conversion ratio. Eggshell was thicker by 6.78% in Lohmann eggs. Haugh units did not differ among freshly laid and stored eggs in Lohmann hens, whereas Haugh units decreased in stored BC eggs (80.5 vs. 76.7 vs. 72.3 at 0, 14, and 30 d of storage). Yolks of BC eggs contained less fat (57.5 vs. 60.8% DM), more protein (32.8 vs. 31.9% DM) and more cholecalciferol (1.25 vs. 1.22 μg/g DM), and showed lower proportion of saturated fatty acids (29.0 vs. 37.0%) and higher proportions of monounsaturated (45.7 vs. 39.6%) and polyunsaturated (25.2 vs. 23.4%) fatty acids. Feeding the omega-3 diet reduced the yolk proportions of saturated (32.5 vs. 33.5%) and monounsaturated (42.0 vs. 43.3%) fatty acids and increased those of polyunsaturated (25.4 vs. 23.2%) and ω-3 (7.05 vs. 2.42%) fatty acids. No effect due to genetics or diet was found on yolk color score or on yolk content in cholesterol, cobalamin, retinol and γ-tocopherol. This study represents the first exhaustive characterization of eggs from Spanish indigenous Black Castellana breed.

The Effects of Vitamin D on Markers of Glucose and Obesity in Postmenopausal Women: A Meta-analysis of Randomized Controlled Trials

PURPOSE

The effect of vitamin D effect on glucose markers and obesity in postmenopausal women remains controversial. The current literature contains little information on vitamin D dosage and duration for optimal efficacy in postmenopausal women. This meta-analysis was undertaken to assess the impact of vitamin D on glucose markers and obesity in postmenopausal women.

METHODS

A number of databases were used dated up to January 5, 2023, with no language restrictions (PubMed/MEDLINE, Web of Science, EMBASE, and Scopus). Treatment response from baseline was estimated from the mean within-group analysis, and SDs were used to calculate the treatment response.

FINDINGS

Nine eligible articles with 12 comparisons qualified for the final quantitative analysis. An overall decrease was noted in fasting blood glucose (weighted mean difference [WMD], -3.56 mg/dL; 95% CI, -5.49 to -1.64; P < 0.001), homeostatic model assessment for insulin resistance (WMD, -1.168 mm; 95% CI, -2.001 to -0.33; P = 0.006), insulin (WMD, -2.26 units; 95% CI, -4.35 to -0.18; P = 0.033), and glycosylated hemoglobin (WMD, -0.41%; 95% CI, -0.54 to -0.29; P < 0.001) after vitamin D administration in postmenopausal women. In subgroup analyses, a notable decrease in fasting blood glucose was detected when the intervention course was ˃6 months and dosage ≤1000 IU/d (WMD, -3.48 mg/dL). The present study showed that vitamin D was not associated with body mass index, body weight, or waist circumference in postmenopausal women.

IMPLICATIONS

Vitamin D is beneficial for glucose markers but not obesity in postmenopausal women. An individualized dosage regimen of vitamin D should be followed depending on the clinical outcome target of postmenopausal women.

The effect of omega-3 supplements on the serum levels of ACE/ACE2 ratio as a potential key in cardiovascular disease: A randomized clinical trial in participants with vitamin D deficiency

Objective

The aim of this randomized controlled clinical trial was to determine the effect of the omega-3 fatty acid supplementations 300 mg per day for 8 weeks on the serum levels of ACE/ACE2 ratio in Jordanian participants with vitamin D deficiency (VDD).

Methods

The physical and clinical characteristic of individuals in both intervention and control randomized controlled clinical trial were measured and analyzed. The comparisons between the two groups and the changes in each group before and after taking omega-3 doses were studied through independent t test and paired t test, respectively. Possible factors that have a role in the changes were determined by multivariate stepwise regression. Follow-up period lasted 10 weeks.

Results

The sample consisted of 82 participants with VDD and a mean age of 37.85 ± 9.85 years. Omega-3 Supplements resulted in a significant decrease in serum ACE levels, ACE/ACE2 ratio and serum 25-hydroxy vitamin D (25OHD). While the change in serum ACE2 levels and serum triglycerides levels were insignificant. Also, a significant increase in serum LDL levels were observed.

Conclusion

It is possible that taking high doses of omega-3 fatty acid supplementations have positive effects on the heart and circulatory system and could protect from COVID-19 or decrease disease severity, in connection with a decrease in the ACE/ACE 2 ratio. On the other hand, omega-3 supplement may have negative effect on cardiovascular system due to the significant increase in serum LDL levels.

The Association Between Vitamin D and Type 2 Diabetes Mellitus Complicated with Non-Alcoholic Fatty Liver Disease: An Observational Cross-Sectional Study

OBJECTIVE

To investigate the association between vitamin D deficiency and NAFLD risk in patients with type 2 diabetes mellitus (T2DM).

METHODS

Overall, 434 patients with T2DM admitted to Hebei General Hospital from January 2019 to December 2019 were selected as the study subjects. According to abdominal ultrasound findings, patients were divided into the NAFLD group and the non-NAFLD group. Participants were divided into two study groups according to the 25-hydroxyvitamin D [25(OH)D] level. 25(OH)D deficiency was defined if 25(OH)D vitamin levels were <20 ng/mL. Chi-square test and one-way analysis of variance were used to compare groups. The relationship between 25(OH)D and NAFLD risk was analyzed using correlation and regression analyses. Furthermore, subgroup analyses were performed to verify the robustness of the results.

RESULTS

The 25(OH)D level in patients with T2DM complicated by NAFLD was significantly lower than in patients with T2DM only. Vitamin D deficiency was highly prevalent among T2DM patients with NAFLD. This study suggested that vitamin D deficiency was an independent factor for developing NAFLD in patients with T2DM. T2DM patients with vitamin D deficiency had 2.045 times higher risk of developing NAFLD than those without vitamin D deficiency. Vitamin D deficiency was associated with high NAFLD preference in T2DM patients with BMI >23kg/m², but not those with BMI ≤23kg/m². The significant correlation between vitamin D deficiency and NAFLD was found in participants with BMI >23kg/m², age ≤65 years, without hypertension, TG <1.7mmol/l, HDL ≥1 mmol/l in men, ≥1.3 mmol/l in women, HBA1C ≤7%, or females.

CONCLUSION

This study suggests that T2DM people with BMI >23kg/m² were more susceptible to NAFLD by vitamin D deficiency and that it is necessary to maintain optimal serum vitamin D levels in this population.

Assessing Oxidative Stress by Thiol/Disulfide Homeostasis Among Vitamin D-Deficient Patients

Objective: Thiol/disulfide (T/DS) homeostasis represents a promising new approach to evaluate oxidative stress. Therefore, we aimed to examine T/DS homeostasis in vitamin D (VitD)-deficient patients.

Methods: We enrolled 154 patients with VitD deficiency and 154 healthy control subjects in the study. For both groups, native thiol, total thiol, and disulfide values were measured. Additionally, considering the obtained 25-hydroxycholecalciferol [25(OH)D] levels, the patient group was further divided into two subgroups (Group 1: <10 ng/mL, Group 2: 10-20 ng/mL), which were compared in more depth according to the specified parameters.

Results: Values of native thiol, total thiol, and disulfide measured in the combination of Groups 1 and 2, comprising individuals with VitD deficiency, proved to be higher in comparison to the control group with statistical significance (p=0.007, p=0.028, and p<0.001, respectively). When subgroups were considered according to VitD classifications, native thiol and total thiol were again higher in Group 1 in comparison to the values obtained for control subjects (p=0.022; p<0.001). While the total thiol level of Group 2 was higher than that of controls (p<0.001), no difference with statistical significance was obtained in the comparison of disulfide levels among the indviduals of Group 1, Group 2, and the controls (p=0.081).

Conclusion: In this study, among patients with VitD deficiency, we have confirmed that values of native thiol and total thiol were increased, while the T/DS balance was found to have shifted in favor of the thiol level.

Correlation Between 25 Hydroxyvitamin D Levels and Nonalcoholic Fatty Liver Disease in Chinese Patients with Type 2 Diabetes Mellitus: A Cross-Sectional Study

Purpose

We aimed to analyze the serum vitamin D level in Chinese patients with type 2 diabetes mellitus (T2DM) and discuss its correlation with nonalcoholic fatty liver disease (NAFLD).

Patients and Methods

A total of 300 patients with T2DM (92 patients without NAFLD and 208 patients with NAFLD) were enrolled, and 25-hydroxyvitamin D [25-(OH)D] levels were compared between the two groups. Second, the NAFLD fibrosis score (NFS) and fatty liver index (FLI) were used to group patients with T2DM complicated by NAFLD, and the differences in serum 25-(OH)D in patients with different degrees of liver fibrosis were compared. Third, multiple regression analysis was used to analyze the independent predictors of liver fibrosis in patients with T2DM complicated by NAFLD.

Results

The level of 25-(OH)D in patients with T2DM complicated by NAFLD was significantly lower than that in patients with T2DM alone. Based on the NFS and FLI, the 25-(OH)D level of the hepatic fibrosis subgroup was significantly lower than that of the subgroup without liver fibrosis. 25-(OH)D was found to be an independent predictor of liver fibrosis in patients with T2DM complicated by NAFLD.

Conclusion

The serum 25-(OH)D level in patients with T2DM complicated by NAFLD was significantly reduced, and the 25-(OH)D level showed a gradual downward trend with the degree of liver fibrosis. Low concentrations of 25-(OH)D may be indicative of the degree of liver fibrosis in diabetic patients.