Table 5. Summary of significant vs. non-significant findings on the effects of Vit D supplementation on six major components of MetS based on the seven RCT papers reviewed.

MetS: Metabolic syndrome; Vit D: Vitamin D; U.S.: United States; BP: Blood pressure

Published year	Author	Number of patients	Duration of study	MetS component(s) significantly improved with Vit D supplementation	MetS component(s) non-significant associations with Vit D supplementation
2018	Cefalo et al. [20]	18  (Italy)	13 weeks	Insulin and glucose metabolism, and abdominal obesity	Dyslipidemia
2019	Lerchbaum et al. [19]	192 (Austria)	12 weeks	Insulin and glucose metabolism	Dyslipidemia, abdominal obesity
2020	Safapour et al. [21]	85  (Iran)	Eight weeks	Insulin and glucose metabolism	Not reported
2017	Raed et al. [15]	70 (U.S.)	18 weeks	BP	Not reported
2017	McMullan et al. [16]	84 (U.S.)	Eight weeks	Not reported	BP
2018	Karefykalis et al. [26]	40 (Sweden)	26 weeks	Not reported	Dyslipidemia, insulin and glucose metabolism, abdominal obesity, prothrombotic state
2019	Angellotti et al. [24]	127 (U.S.)	48 weeks	Not reported	Dyslipidemia and Pro-inflammatory state