🧬 Family & Essentiality

🌿 Plain-Language Summary

Polyphenols are a diverse family of plant compounds with antioxidant and cell-signalling activity. They are not essential nutrients like vitamins, but regular intake of polyphenol-rich foods contributes to a balanced dietary pattern.

🌱 Subgroups & Examples

• Flavonoids: quercetin (onion), catechins (tea, cocoa), anthocyanins (berries)
• Phenolic acids: caffeic acid (coffee), ferulic acid (grains)
• Stilbenes: resveratrol (grapes, red wine)
• Lignans: secoisolariciresinol (flaxseed)

⚡ Absorption & Bioavailability

• Food matrix & gut microbiome: metabolites, not parent compounds, often mediate effects
• Processing/cooking: can either increase or decrease availability depending on compound

🇦🇺 Australian NRVs

❌ No NRVs are set for polyphenols. Public health advice encourages variety in plant foods (vegetables, fruits, whole grains, legumes, nuts, tea, cocoa).

🥗 Food Sources

• Colourful fruits & vegetables (berries, citrus, leafy greens)
• Tea, coffee, cocoa; olives and extra-virgin olive oil
• Whole grains, legumes, nuts, seeds, herbs & spices

🧪 Testing & Monitoring

• No routine clinical test
• Research uses biomarkers or urinary metabolites

🔗 Interactions

• Polyphenols can reduce non-heme iron absorption — separate from iron supplements if advised
• May interact with certain medicines — seek professional guidance

📊 Evidence Snapshot

• 🧪⚖️ Growing evidence: Higher intakes from foods linked with favourable cardiometabolic markers
• ⚠️❌ Unproven/hype: High-dose single-compound supplements not consistently supported