Tannic Acid in Herbal Tea: Levels, Taste & Health Effects

Tannic acid (a hydrolyzable tannin) imparts astringency and bitterness. Content varies widely:

• High: Black tea, green tea, oak bark, witch hazel.
• Moderate: Rooibos, yerba mate, pomegranate peel.
• Low: Chamomile, peppermint, ginger, hibiscus.

Physiologic Effects

• Antioxidant, antimicrobial, antiviral (in vitro).
• May inhibit non-heme iron absorption—consume between meals if anemic.
• GI irritation at high doses (nausea, constipation).
• Potential drug interactions (chelates metals).

Moderate intake (3–4 cups/day) is safe for most. Decaf reduces tannins minimally.