TABLE 2.

Summary of herb-micronutrient interactions and their mechanisms¹

Phytochemical	Micronutrient affected	Effect and interaction mechanism
Plant polyphenols (tea catechins, phloretin, quercetin)	Iron	Reduced absorption via complexation
	Folate, ascorbate	Reduced absorption via uptake transporter inhibition
Silymarins	Iron	Reduced absorption via complexation
Phytic acid	Calcium, iron, zinc	Reduced absorption via complexation
St. John's wort (hyperforin)	Vitamin D3	Enhanced plasma clearance via induction of CYP3A4 metabolism

¹CYP, cytochrome P450.