Stilbenes (Resveratrol) in Plant Foods

A 100g serving of blueberries (~1 cup) provides approximately 32 mg stilbenes. A cup of red grapes (~160g) delivers ~19 mg. A small handful of peanuts (~30g) provides ~4 mg. A typical Western diet provides 0.5–5 mg resveratrol daily, while Mediterranean diets with regular wine and grape consumption may reach 10–30 mg. However, bioavailable resveratrol reaching systemic circulation is much lower due to limited intestinal absorption and first-pass metabolism.

Stilbenes are a class of polyphenols synthesised by plants in response to stress, particularly fungal attack. Resveratrol is the most studied stilbene, found primarily in red grapes (~12 mg/100g), blueberries (~32 mg/100g), red wine, peanuts (~14 mg/100g), and various berries. Stilbenes are concentrated in the skins of grapes and berries, so whole fruits provide more than juiced versions. Other plant sources include mulberries, pistachios, and cranberries. Stilbenes act as phytoalexins — plant defence compounds with potential antioxidant and anti-inflammatory benefits in human physiology.

Resveratrol is a stilbene — a type of polyphenol — synthesised by plants as a protective compound against pathogenic fungi and UV radiation. It is most abundant in the skins of grapes (especially red and purple varieties) and berries. Resveratrol production increases when plants experience stress, making it an example of a phytoalexin. In human diets, resveratrol has been studied for its potential to activate cellular stress-response pathways (SIRT1), support mitochondrial function, and provide antioxidant and anti-inflammatory benefits.

Stilbenes are one of several major polyphenol classes in plant foods. Flavonoids (found in berries, tea, cocoa) are the most abundant polyphenols by weight. Phenolic acids (in whole grains, seeds, legumes) and lignans (in flaxseeds, sesame) are also prevalent. While stilbenes represent a smaller portion of total dietary polyphenols, resveratrol is uniquely well-studied due to its SIRT1-activating properties. The optimal dietary approach combines diverse polyphenol sources: berries and grapes for stilbenes, tea and cocoa for flavonoids, whole grains for phenolic acids, and seeds for lignans.

Stilbene stability depends on temperature, pH, and processing method. Fresh berries and whole grapes retain maximum stilbene content. Light steaming or gentle heating minimally affects stilbenes, but prolonged boiling or high-temperature cooking can reduce content by 20–40%. Freezing preserves stilbenes effectively — frozen berries maintain most of their stilbene content when thawed. Fermentation (in wine production) can increase apparent resveratrol extraction from grape skins, though overall bioavailability remains modest. Juice processing removes skin-based stilbenes, reducing content by 50–80% compared to whole fruit.