The combination of quercetin and curcumin is stronger than that of either individual treatment alone (Heeba et al 2014; Kim et al 2015; Zhang et al 2015; Sharma et al 2016; Wang et al 2016; Mutlu Altundağ et al 2018; Güran et al 2019; Kundur et al 2019; Srivastava and Srivastava 2019; Mansourizadeh et al 2020; Jiang et al 2021; Mutlu Altundağ et al 2021).
The combination of curcuminoids with both piperine and quercetin seems to have the greatest synergy and result in greater absorption and bioactivity (Kaur et al 2016).
Magnesium and vitamin D
Magnesium is a well known co-factor in vitamin D metabolism enzymes, including 25-hydroxylase and 1α-hydroxylase. Additionally, magnesium seems to be involved in vitamin D binding protein.