FRAP Antioxidant Ranking

FRAP (Ferric Reducing Antioxidant Power) measures a food's total capacity to donate electrons and reduce oxidised molecules. It's a fast, reproducible assay that reflects the combined reducing power of all antioxidants in a food extract — polyphenols, vitamin C, vitamin E, carotenoids, and others. Unlike ORAC (which measures radical absorbance) or DPPH assays, FRAP specifically tests reduction capacity at low pH, making it particularly sensitive to flavonoids and phenolic acids.

Dried herbs and spices dominate the FRAP rankings — cloves, dried oregano, ginger, cinnamon, and turmeric all score exceptionally high. Among everyday whole foods, dark chocolate and cocoa powder, coffee, green and black tea, elderberries, and artichokes consistently rank highest. The key pattern is that concentration matters: dried foods and extracts score higher than fresh versions simply because water has been removed.

FRAP is a useful proxy for polyphenol richness, but it's not a direct health score. The human body doesn't absorb and use antioxidants the same way a test tube does — bioavailability, food matrix, gut microbiome, and context all affect whether the antioxidant activity translates to a real benefit. Use FRAP as a guide to identifying plant foods rich in phenolic compounds, not as a direct ranking of health value. A diverse range of colorful plant foods will always outperform optimising for a single metric.

Yes, significantly. Boiling leaches water-soluble polyphenols into cooking liquid, which can reduce FRAP values by 20–50%. Roasting and baking can cause some polyphenol degradation but also concentrate antioxidants as moisture is lost. Steaming retains more antioxidant activity than boiling. The values in this database represent raw or standard-preparation values — actual FRAP after cooking will vary depending on method, time, and temperature.

Not directly — and the gap between test-tube scores and real-body activity can be dramatic. Dr. Michael Greger at NutritionFacts.org highlights a striking example: spinach ranks #1 in standard chemical antioxidant assays like FRAP and ORAC, yet when researchers measured actual cellular antioxidant activity — how antioxidants protect living cells — spinach didn't even make the top ten. Beets, by contrast, rank #1 in cellular antioxidant activity despite a more modest FRAP score. FRAP measures how foods slow down a specific chemical reaction in a test tube, a reaction that doesn't occur in living cells. Bioavailability — how much is actually absorbed, how gut bacteria transform it, and whether it reaches target tissues — determines real-world impact far more than any lab score. Use FRAP as a useful guide to polyphenol richness, but don't use it to compare foods head-to-head for health value.

FRAP values are expressed in µmol Fe²⁺ equivalents per 100g (micromoles of ferrous iron equivalent per 100 grams of food). This reflects how many micromoles of ferric iron (Fe³⁺) the food's antioxidants can reduce to ferrous iron (Fe²⁺) under standard conditions. Some studies express FRAP per serving or per 100 mL for liquids. When comparing values across databases, always check the unit — mmol/100g (millimoles) means the same number would be 1,000× higher than µmol/100g.

By weight, yes — dramatically so. Cloves, dried oregano, and ground ginger can exceed 100,000 µmol Fe²⁺/100g, while fresh berries typically range from 5,000–15,000. The reason is concentration: spices have had nearly all moisture removed, densifying their polyphenol content. In practice, though, you consume a few grams of spice per dish versus 100–200g of fruit. Per realistic serving, berries, coffee, tea, and cocoa often contribute more total FRAP to a diet than spices do.

FRAP values strongly correlate with total polyphenol content because polyphenols are the dominant reducing compounds in plant foods. However, not all polyphenols have the same FRAP contribution — some flavonoids are stronger reducing agents than others, and non-polyphenol antioxidants like vitamin C also add to FRAP scores. For the most comprehensive view of a food's polyphenol profile, the Phenol-Explorer polyphenol database provides compound-by-compound breakdowns.

Yes — unlike ORAC, which was discontinued by the USDA in 2012, FRAP remains widely used in both food science and clinical nutrition research. It is valued for its simplicity, speed, and reproducibility. The comprehensive FRAP database used here, compiled by researchers at the University of Oslo, covers over 1,000 plant-based foods and continues to be cited in peer-reviewed studies on dietary antioxidant intake and health outcomes.

Per realistic serving size, coffee and tea are the largest contributors to total antioxidant intake in most plant-based diets — a single cup of coffee provides roughly 200–500 µmol Fe²⁺ equivalent. After beverages, the highest per-serving contributors include dark chocolate, blueberries, prunes, red kidney beans, artichokes, and red cabbage. Spices add meaningful amounts when used generously in cooking. Eating a variety across all these categories daily produces the most consistent and broad antioxidant coverage.

No — isolated antioxidant supplements have consistently underperformed compared to whole foods in clinical trials. Vitamin E and beta-carotene supplements in particular showed no benefit and in some cases increased risk in large randomised trials. The advantage of whole high-FRAP foods is that they deliver hundreds of polyphenols simultaneously, along with fibre, minerals, and other bioactive compounds that work synergistically in ways that isolated nutrients cannot replicate.