What do polyphenols do?

Research suggests polyphenols may:

• Reduce inflammation by helping regulate inflammatory pathways.

• Protect cells from oxidative stress, acting as antioxidants (although this is only one of their mechanisms).

• Support heart health by improving blood vessel function and helping maintain healthy cholesterol levels.

• Feed your gut microbiome. Many polyphenols aren't absorbed until they reach the large intestine, where gut bacteria break them down into beneficial compounds. In return, polyphenols help beneficial bacteria thrive.

• Support brain health, with some evidence suggesting benefits for memory, cognition and healthy ageing.

• Help regulate blood sugar, potentially improving insulin sensitivity.

The four main groups

1. Flavonoids (the largest group)

   • Berries

   • Apples

   • Onions

   • Citrus fruits

   • Dark chocolate

   • Tea

2. Phenolic acids

   • Coffee

   • Wholegrains

   • Cherries

   • Blueberries

3. Stilbenes

   • Grapes

   • Red wine (although the alcohol isn't beneficial, so grapes are the healthier source)

   • Peanuts

4. Lignans

   • Flaxseeds

   • Sesame seeds

   • Wholegrains

The richest food sources

Some of the highest-polyphenol foods include:

• Cloves and many dried herbs and spices

• Cocoa (especially high-cocoa dark chocolate)

• Blueberries, blackberries and blackcurrants

• Pomegranates

• Extra virgin olive oil

• Green tea

• Coffee

• Red cabbage

• Artichokes

• Walnuts and pecans

Why variety matters

Different plants contain different polyphenols, so eating a wide range of colours is more beneficial than eating large amounts of one food.

A useful target is:

• Aim for 30 different plant foods each week (including herbs, spices, nuts, seeds, legumes, wholegrains, fruit and vegetables).

• "Eat the rainbow" by choosing foods with different colours.

This approach has also been linked with a more diverse and resilient gut microbiome.

What about supplements?

Most experts recommend getting polyphenols from whole foods rather than supplements because:

• Whole foods contain thousands of compounds that work together.

• The fibre helps nourish your gut bacteria.

• Some high-dose supplements haven't consistently shown the same benefits and may not be absorbed as well.

An easy day's worth

You don't need anything exotic. For example:

• Breakfast: Porridge with blueberries, walnuts and cinnamon.

• Lunch: Mixed bean salad with tomatoes, spinach, olives and extra virgin olive oil.

• Afternoon: Green tea and a square of 85% dark chocolate.

• Dinner: Lentil curry with onions, garlic, turmeric, ginger and mixed vegetables.

That single day would provide hundreds of different polyphenol compounds.