Vitamin D3 supplementation improves glycemic control in type 2 diabetic patients: Results from an Italian clinical trial

The effects of vitamin D supplementation on serum lipid profiles in people with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Introduction

People with type 2 diabetes (T2D) are highly susceptible to the development of cardiovascular diseases. Previous studies have suggested that the application of vitamin D may offer potential benefits in improving lipid profiles, but these effects remain controversial.

Methods

This systematic review and meta-analysis focused on the effects of vitamin D supplementation on serum lipid profiles in people with T2D. Randomized controlled trials (RCTs) assessing the effects of vitamin D supplementation on lipid profiles and published before September 19th, 2023, were identified in PubMed, Embase, and Cochrane Library. This review protocol was registered in the PROSPERO (CRD42023461136). The random-effects model was employed to estimate unstandardized mean differences (MD) and 95% confidence intervals (CIs). The quality of studies was assessed by the Cochrane Risk of Bias tool 2.

Results

Overall, 20 RCTs involving 1711 participants were included. Results indicated that vitamin D supplementation significantly improves serum high-density lipoprotein (HDL) (MD: 1.63 mg/dL, 95% CI: 0.19 to 3.08, P = 0.03), and triglyceride (TG) levels (MD: -8.56 mg/dL, 95% CI: -15.23 to -1.89, P = 0.01). However, vitamin D supplementation failed to improve low-density lipoprotein (LDL) levels and total cholesterol (TC) levels. Subgroup analyses and meta-regressions suggested that higher doses of vitamin D supplementation and shorter duration of intervention were more likely to have favorable effects on lipid profiles. Moreover, participants with lower baseline BMI and higher serum 25-hydroxy vitamin D levels exhibited greater improvements in lipid profiles following vitamin D supplementation.

Conclusions

This meta-analysis highlighted the effects of vitamin D supplementation on improving serum HDL and TG levels while not exhibiting significant improvements in LDL and TC levels. Further long-term and high-quality studies are still needed to draw more precise conclusions.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=461136.

A Randomized, Placebo-Controlled Crossover Study to Evaluate Postprandial Glucometabolic Effects of Mulberry Leaf Extract, Vitamin D, Chromium, and Fiber in People with Type 2 Diabetes

INTRODUCTION

Reducing postprandial (PP) hyperglycemia and PP glucose excursions is important for overall glycemic management. Although most therapeutic lifestyle interventions that reduce caloric intake would affect this, there is no particular nutritional intervention favored.

METHODS

We evaluated the effects of a novel natural food adjuvant combining mulberry leaf extract (MLE) with other bioactive ingredients, in people with type 2 diabetes (T2D) originating from Asia, on improving PP glucometabolic response in a randomized controlled exploratory crossover, two-center study (USA, Singapore). A 2-g blend of 250 mg MLE [containing 12.5 mg of 1-deoxynojirimycin (DNJ)], fiber (1.75 g), vitamin D₃ (0.75 μg), and chromium (75 μg), compared with a similar blend without the MLE, was sprinkled over a 350-kcal breakfast meal (55.4 g carbs) and PP blood glucose (primary exploratory endpoint), insulin, and incretin hormones (GLP-1, GIP) were evaluated in blood samples over 3 h. Changes in incremental areas under the concentration curve (iAUC) and maximum concentrations (C_max) were compared.

RESULTS

Thirty individuals (12 women, mean age 59 years, HbA1c 7.1%, BMI 26.5 kg/m²) were enrolled and the MLE-based blend relative to the blend without MLE significantly reduced glucose iAUC at 1 h (- 20%, p < 0.0001), 2 h (- 17%, p = 0.0001), and 3 h (- 15%, p = 0.0032) and C_max [mean (95% CI) difference - 0.8 (- 1.2, - 0.3) mmol/L, p = 0.0006]. A statistically significant reduction in 1 h insulin iAUC (- 24%, p = 0.0236) was observed, but this reduction was no longer present at either 2 h or 3 h. No difference in GLP-1 was seen, but GIP response (iAUC and C_max) was less with the MLE-based blend.

CONCLUSIONS

The observation of a significant glucose reduction paralleled with a significant lower insulin response supports a reduced gastrointestinal glucose absorption. These results support the use of a 2-g natural blend of MLE, fiber, vitamin D, and chromium in T2D as a convenient dietary adjuvant to improve PP glucometabolic response.

CLINICALTRIALS

gov identifier NCT04877366.

Lifestyle Improvements and Vitamin D Supplementation Play an Important Role in the Prevention of Childhood Diabetes

Objective

This study was to investigate the characteristics of insulin secretion and the 25-hydroxyvitamin D3 (25(OH)D3) levels in children with obesity.

Methods

A retrospective analysis was conducted among children who underwent health checkups in the pediatric healthcare department of our hospital from January 2018 to January 2021, and they were divided into a normal group and an obese group according to their BMI. The insulin secretion and the 25(OH)D3 levels of the two groups of children were compared. A total of 721 children were included in the study, including 591 in the normal group and 130 in the obese group, with an obesity rate of 18.03%.

Results

The blood glucose of the normal group was 4.55 ± 1.75 mmol/L, and the 2 h PG was 7.51 ± 2.11 mmol/L; in the obesity group, they were 6.03 ± 2.16 mmol/L and 8.92 ± 3.24 mmol/L, respectively. The FPG and 2 h PG in the obese group were significantly higher than those in the normal group (all P < 0.05). The incidence of IFG/IGT in the normal group was 5.24% (31/591), and the incidence of DM was 3.71% (22/591); the incidence of IFG/IGT in the obese group was 14.62% (19/130), and the incidence of DM was 13.08% (17/130). The incidences of IFG/IGT and DM in the obese group were significantly higher than those in the normal group (P < 0.05). The FINS of the children in the normal group was 18.46 ± 3.15 μU/mL, and the HOMA-IR was 2.64 ± 0.62; the above indicators in the obese group were 19.11 ± 4.72 μU/mL and 3.01 ± 0.83, respectively. The FINS and HOMA-IR in the obese group were significantly higher than those in the normal group (P < 0.05). The serum 25(OH)D3 level in the normal group was 28.15 ± 5.27 ng/mL, of which 556 cases were normal in 25(OH)D3 and 35 cases were deficient in 25(OH)D3. The serum 25(OH)D3 level in the obese group was 24.35 ± 4.51 ng/mL, of which 112 cases were normal in 25(OH)D3 and 18 cases were deficient in 25(OH)D3. The level of serum 25(OH)D3 in the normal group was significantly higher than that in the normal group, and the ratio of 25(OH)D3 deficiency was significantly lower than that in the normal group (P < 0.05).

Conclusions

The blood glucose level of childhood obesity was significantly increased, the incidence of abnormal glucose metabolism and diabetes was significantly increased, and the level of 25(OH) vitamin D3 was significantly decreased. Lifestyle improvements and vitamin D supplementation play an important role in the prevention of childhood diabetes. Because the major causes of childhood obesity are excessive caloric intake and lack of exercise, the most effective and direct measures to prevent obesity are a reasonable lifestyle, reasonable eating habits, and moderate exercise. Although genetics are critical, there is no reliable way to eliminate obesity genes in the human body. Therefore, the role of obesity genes is required to be ultimately eliminated by reduced caloric intake and increased physical activity.

Comparative Analysis of Clinical Effects of Insulin Aspart Combined with Acarbose and Metformin in the Treatment of Diabetes Mellitus

Objective

To investigate the clinical effect of Insulin aspart 30 combined with acarbose and metformin enteric-coated tablets in the treatment of diabetes mellitus.

Methods

90 diabetic patients admitted to our hospital from January 2019 to December 2021 were selected as the research subjects, and the patients were randomly divided into group A (n = 30, using insulin aspart 30 alone), group B (n = 30, using insulin aspart 30 combined with metformin enteric-coated tablets), and group C (n = 30, using insulin aspart 30 combined with acarbose). The blood glucose balance before meals and before going to bed was maintained in the three groups of patients, and the blood glucose fluctuations, time to target, hypoglycemia, insulin dosage, and daily consumption of the three groups were compared.

Results

There was no significant difference in blood glucose and average blood glucose at each time point before treatment in the 3 groups of patients (P > 0.05); compared with the blood glucose and average blood glucose at each time point after reaching the target in the three groups, the blood glucose after dinner in group A was significantly higher than that in groups B and C; at 2 : 00, the blood glucose of group A was significantly higher than that of group B (P < 0.05); there was no significant difference in blood glucose and average blood glucose at other time points (P > 0.05). There was no significant difference in blood glucose standard deviation, LAGE, and PPGE at each point in the three groups before treatment (P > 0.05); the standard deviation of blood glucose, LAGE, and PPGE at each point of the three groups of patients after reaching the standard were compared with those in the same group before treatment, and the differences were statistically significant (P < 0.05); there were statistically significant differences in blood glucose standard deviation, LAGE, and PPGE among the 3 groups after reaching the standard (P < 0.05). Compared among the three groups, the standard deviation of blood glucose and LAGE level at each point after reaching the standard, the difference between group B, group C, and group A was statistically significant (P < 0.05); however, there was no significant difference between the patients in group B and group C (P > 0.05); the level of PPGE in group A was higher than that in group B, which was higher than group C, and between group C and group A, the difference was statistically significant (P < 0.05). The time of reaching the standard in 3 groups was statistically significant (P < 0.05); there was no significant difference in the time of reaching the standard between group B and group C (P > 0.05). There was no significant difference in the incidence of hypoglycemia among the 3 groups (P > 0.05); there were significant differences in the proportion of insulin twice a day among the three groups (P < 0.05); there were statistically significant differences in daily insulin dosage among the 3 groups after reaching the standard (P < 0.05). The daily consumption of the three groups of patients after reaching the standard was compared, the difference was statistically significant (P < 0.05), and there was no significant difference between group A and group B (P > 0.05).

Conclusion

The effect of insulin aspart 30 alone in the treatment of diabetic patients is not good, it will lead to a large fluctuation of blood sugar in the patient's body, and the time required to reach the standard is relatively long; the use of insulin aspart 30 combined with metformin enteric-coated tablets or acarbose can effectively reduce the blood sugar fluctuation range of diabetic patients and reduce the number of insulin injections, and insulin aspart 30 combined with metformin en teric-coated tablets can also greatly reduce the daily insulin dosage and daily consumption cost of diabetic patients.