Higher intakes of dietary caffeine are associated with 25-hydroxyvitamin D deficiency

Dietary Consumption With Vitamin D Status Among Pregnant Women: A Descriptive-Analytic Study

AIM

This study aimed to investigate the relationship between vitamin D status and diet between pregnant and non-pregnant women who attended a Maternity Teaching Hospital (MTH) in Sulaymaniyah, Iraq.

MATERIALS AND METHODS

A descriptive-analytic (cross-sectional) study was conducted at the MTH in Sulaymaniyah, Iraq. Data was collected from January to October 2022, including demographics, obstetric information, and dietary data. Vitamin D levels were measured using the Roche Elecsys assay (Roche Diagnostics, Indianapolis, Indiana, United States). The non-pregnant group consisted of women who were not pregnant at the time of this study, and the pregnant group had women with second trimester pregnancy at the time of enrollment.

RESULT

The study revealed a significant prevalence of vitamin D deficiency among pregnant women. In the study, pregnant participants (56.0% aged 30-39) and non-pregnant participants (54.3% aged 20-29) had similar ages (p>0.05). Both groups mostly had overweight individuals, with pregnant participants having a slightly higher mean body mass index (BMI). While vitamin D deficiency was more prevalent among pregnant women, the differences were not statistically significant. Notably, higher dairy intake was positively associated with higher vitamin D levels. Urban residency was common in both groups. Dietary habits were mostly similar, except for tea consumption (p<0.05), with non-tea drinkers having higher vitamin D levels. However, dietary patterns did not strongly correlate with vitamin D levels in the non-pregnant group.

CONCLUSION

This study reveals a significant prevalence of vitamin D deficiency among pregnant women, although the differences between pregnant and non-pregnant groups were not statistically significant. The positive association between higher dairy intake and increased vitamin D levels underscores the potential impact of dietary choices on vitamin D status during pregnancy. However, the study also suggests that dietary patterns alone may not strongly correlate with vitamin D levels in non-pregnant women. Overall, this highlights the importance of addressing vitamin D deficiency in pregnant women and underscores the need for personalized dietary guidance, taking into account individual preferences and habits to promote better maternal health.

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.

Effect of resistance training on lipid profile in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Physical exercise decreases cardiovascular risk and can alter the lipid profile in postmenopausal women. Although it is believed that resistance training can potentially decrease serum lipid levels in postmenopausal females, the evidence remains inconclusive. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to clarify the impact of resistance training on the lipid profile in postmenopausal women.

METHODS

Web of Science, Scopus, PubMed/Medline and Embase were searched. RCTs that evaluated the effect of resistance training on total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels were included in this review. Effect size was estimated using the random effects model. Subgroup analyses based on age, duration of intervention, pre-enrolment serum lipid levels and body mass index were performed.

RESULTS

Data pooled from 19 RCTs revealed that resistance training can reduce TC [weighted mean difference (WMD) -11.47 mg/dl; p = 0.002], LDL-C (WMD -8.48 mg/dl; p = 0.01) and TG (WMD -6.61 mg/dl; p = 0.043) levels. TC levels decreased particularly in subjects aged < 60 years (WMD -10.77 mg/dl; p = 0.003), in RCTs lasting < 16 weeks (WMD -15.70 mg/dl; p = 0.048), and in subjects with hypercholesterolaemia (WMD -12.36 mg/dl; p = 0.001) or obesity (WMD -19.35 mg/dl; p = 0.006) before RCT enrolment. There was a significant decrease in LDL-C (WMD -14.38 mg/dl; p = 0.002) levels in patients with LDL-C ≥ 130 mg/dl before trial enrolment. Resistance training reduced HDL-C (WMD -2.97 mg/dl; p = 0.01) levels particularly in subjects with obesity. TG (WMD -10.71 mg/dl; p = 0.01) levels decreased particularly when the intervention lasted < 16 weeks.

CONCLUSION

Resistance training can decrease TC, LDL-C and TG levels in postmenopausal females. The impact of resistance training on HDL-C levels was small, and was only observed in individuals with obesity. The effect of resistance training on the lipid profile was more notable in short-term interventions and in postmenopausal women with dyslipidaemia or obesity before trial enrolment.

Associations between vitamin D levels and dietary patterns in patients with Hashimoto's thyroiditis

Introduction

Vitamin D insufficiency is a global health problem affecting healthy and diseased individuals, including patients with Hashimoto's thyroiditis (HT). Identifying dietary factors that may affect vitamin D levels and providing dietary guidelines accordingly can alleviate this problem. We therefore aimed to identify still unknown associations of dietary patterns, assessed through the Food Frequency Questionnaire (FFQ) with vitamin D blood levels.

Materials and methods

FFQ was collected from 459 patients from Croatian Biobank of Patients with Hashimoto's thyroiditis (CROHT), while total 25(OH)D was measured from their stored serum samples. We performed linear regression analysis between vitamin D levels and weekly intake of 24 food groups in 459 patients with HT (ALL), and in two disease-severity groups (MILD and OVERT).

Results

The main results of our study are observations of: (1) an inverse association between vitamin D levels and coffee consumption (ALL: β = -0.433, p = 0.005; OVERT: β = -0.62, p = 0.008); (2) an inverse association between vitamin D levels and sweets consumption (ALL: β = -0.195, p = 0.034; OVERT: β = -0.431, p = 0.006); (3) positive association between vitamin D levels and vegetable consumption (ALL: β = 0.182, p = 0.019; OVERT, β = 0.311, p = 0.009). Importantly, effect sizes of all three associations were more prominent in HT patients with prolonged and more severe disease (OVERT).

Conclusion

Further research into the functional and causal relationships of the observed associations is important to provide guidance regarding coffee/sugar intake on vitamin D status. A well-balanced diet can help prevent vitamin D deficiency and improve the quality of life of patients with HT, especially those in later stages of disease characterized by greater metabolic imbalance.