Table 2. Assessment of the quality of the studies included in the systematic review: a summary of risk of bias (Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0).

	Selection Bias		Performance Bias	Detection Bias	Attrition Bias	Reporting Bias	Other Bias
	Random sequence generation	Allocation concealment	Blinding of participant and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Diet/supplement compliance assessment
Sodium
Dodson15	unclear	unclear	low*	low	low	low	low
Magnesium
Guerrero-Romero16	low	unclear	low	unclear	low	low	low
Vitamin C
Darko17	unclear	unclear	low	unclear	low	low	low
Mullan18	unclear	unclear	low	unclear	low	low	low
Vitamin D
Witham19	low	low	low	unclear	low	low	low
Sugden20	low	low	low	unclear	low	low	low
Shab-Bidar21	unclear	unclear	low	unclear	low	low	low
Nasri22	low	low	low	unclear	low	low	low
Al-Zahrani	low	low	high	unclear	high	unclear	unclear
Nikooeh	unclear	unclear	unclear	unclear	unclear	unclear	low
Breslavsky	unclear	unclear	low	unclear	unclear	low	unclear

*Blinding of participants and personnel was not applicable because the intervention was dietary advice only.