Does vitamin D supplementation modulate metabolic risk factors of cardiovascular disease? A systematic review and meta-analysis of clinical trials.

Suhad Abumweis, Sarah Alqadi, Ala'a Al Tarteer, Waed Alrefai, Foad Alzoughool, Stephanie Jew, Taima Qudah

Journal: Asia Pacific journal of clinical nutrition 2026;35(4):631-643

PMID: 42521227

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Plain Language Summary

Cardiovascular disease is the leading cause of death worldwide, and vitamin D has been proposed to influence several of the biological pathways that contribute to it. This systematic review and meta-analysis of 45 randomised control trials investigated whether vitamin D supplementation can affect risk factors related to cardiovascular disease, such as cholesterol levels, blood pressure, and blood sugar control.

The results showed that vitamin D supplementation produced small but meaningful improvements in several cardiovascular risk markers. Individuals taking vitamin D had lower levels of low-density lipoprotein cholesterol, lower blood pressure, and better blood sugar control, including improvements in both fasting blood sugar levels and longer-term blood sugar balance (measured by a test called HbA1c). However, no significant improvements were found for high-density lipoprotein cholesterol, triglycerides (blood fats), diastolic blood pressure, markers of inflammation in the blood, or body weight. Supplementation in individuals over 55 was especially beneficial to blood pressure and low-density lipoprotein cholesterol.

In conclusion, vitamin D supplementation may produce small but meaningful improvements in low-density lipoprotein cholesterol, blood pressure, and blood sugar in adults, though the effects are modest and not consistent across all cardiovascular risk markers. These findings could be used by healthcare professionals to understand the variable effects of vitamin D supplementation on cardiovascular disease risk factors, and to support targeted recommendations, particularly for patients who are vitamin D deficient or older.

Abstract

BACKGROUND AND OBJECTIVES

Vitamin D has been proposed to influence several cardiometabolic risk factors; however, evidence from randomized controlled trials (RCTs) and recent meta-analyses remains inconsistent regarding the magnitude of these effects. This meta-analysis evaluated the effects of vitamin D supplementation on lipid profile, blood pressure, and glycaemic parameters, and explored whether age and baseline serum vitamin D concentrations modified these associations.

METHODS AND STUDY DESIGN

A systematic review and meta-analysis of RCTs was conducted to compare oral vitamin D supplementation with placebo in adults. PubMed, the Cochrane Library, and ClinicalTrials.gov were searched systematically. Risk of bias was as-sessed using the Cochrane risk-of-bias tool. Pooled effect sizes with 95% confidence intervals (CIs) were estimated using random-effects models.

RESULTS

A total of 14,051 abstracts were identified, and 45 RCTs were included in the final analysis. Vitamin D supplementation significantly reduced low-density lipoprotein cho-lesterol (LDL-C) by 0.136 mmol/L (95% CI: -0.215, -0.056), systolic blood pressure (SBP) by 2.79 mm Hg (95% CI: -4.65, -0.94), fasting blood glucose (FBG) by 0.11 mmol/L (95% CI: -0.19, -0.04), and hemoglobin A1c (HbA1c) by 0.164% (95% CI: -0.32, -0.01) compared with placebo. Subgroup analyses showed reductions in SBP and LDL-C among participants aged ≥55 years, whereas FBG was reduced in those aged <55 years. While favorable effects on FBG and HbA1c were observed with a baseline blood level of vitamin D of less than 50 nmol/L.

CONCLUSIONS

Vitamin D supplementation may modestly improve selected cardiomet-abolic risk factors. Age and baseline vitamin D status may influence these effects, although their clinical sig-nificance remains uncertain. Further well-designed RCTs are needed.

Address: Department of Clinical Nutrition and Dietetics, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, Jordan. Email: [email protected].; Independent Researcher, Jordan.; Department of Health Science and Biostatistics, Swinburne University of Technology, Hawthorn, Australia.; Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, Jordan.; Faculty of Health Sciences, Fujairah Women's College, Higher Colleges of Technology, UAE.; Independent Researcher, Canada.; College of Pharmacy and AAU Health and Biomedical Research Center, Al Ain University, Abu Dhabi, UAE.

DOI: 10.6133/apjcn.202608_35(4).0007