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Key takeaways
• Strawberries are the richest dietary source of fisetin at approximately 160 μg per gram fresh weight (1).
• A 250 g serving of strawberries delivers approximately 40 mg of fisetin — well above typical dietary intake, but 3–20 times below common supplement capsule doses.
• Apples, persimmons, grapes, onions, and cucumbers carry meaningful but smaller amounts (1).
• Average dietary intake in Western populations is 0.4 to 1 mg per day — several hundredfold below any studied supplement dose (2).
• Dietary intake cannot substitute for supplement dosing at the doses used in senolytic studies — matching a 1,400 mg pulsed protocol dose would require approximately 9 kg of strawberries.
• Sustained dietary flavonoid intake has independent evidence for cardiovascular and mortality endpoints (8,9), and a strawberry-rich, polyphenol-rich diet is a defensible foundation regardless of supplement use.
Quick answer
Strawberries are the richest natural source of fisetin at approximately 160 μg per gram fresh weight — a 250 g serving delivers approximately 40 mg (1). Apples, persimmons, grapes, onions, and cucumbers contain smaller amounts. Average dietary fisetin intake in Western populations is 0.4 to 1 mg per day (2). Dietary intake cannot substitute for supplement doses used in senolytic studies (which target 20 mg/kg pulsed doses, roughly 1,400 mg for a 70 kg adult). But sustained dietary flavonoid intake has independent evidence for cardiovascular and mortality outcomes (8,9), and a strawberry-rich, polyphenol-rich dietary pattern is a legitimate intervention independent of any supplement approach. This article ranks the food sources and puts them in dietary context. For the supplement dose story, see our dedicated dosage article.
The ranked list — Kimira 2019
The definitive food-content ranking comes from a 2019 Japanese analysis by Kimira and colleagues that measured fisetin content across the standard Japanese dietary basket (1). Their measurements are consistent with earlier US and European databases and are the most widely cited reference in the fisetin literature.
|
Food source |
Fisetin (μg per g fresh weight) |
Fisetin per typical serving |
|
Strawberries |
~160 |
~40 mg per 250 g punnet |
|
Apples (with skin) |
~27 |
~5 mg per medium apple |
|
Persimmons |
~11 |
~2 mg per medium persimmon |
|
Lotus root |
~6 |
~1 mg per typical portion |
|
Onions |
~5 |
~0.6 mg per half medium onion |
|
Grapes |
~4 |
~0.5 mg per 100 g bunch |
|
Cucumbers |
~1 |
Trace amounts per portion |
|
Kiwi |
~1 |
Trace amounts per fruit |
Two things stand out from this table. First, the gap between strawberries and everything else is unusually large — strawberries contain roughly six times more fisetin per gram than the next-richest source (apples). Fisetin is highly concentrated in strawberries in a way that makes them almost uniquely useful for dietary intake.
Second, even the highest dietary intake possible from these sources delivers doses several-fold below any supplement capsule strength. A person eating a very generous 500 g of strawberries daily — an unusually high strawberry intake — would consume approximately 80 mg of fisetin per day. This is meaningful nutritionally but still 6 to 60-fold below the daily doses used in continuous-dose supplement products, and hundreds-fold below the pulsed 1,400 mg dose used in trials.
Why strawberries specifically?
Strawberry’s exceptional fisetin content reflects a biosynthetic quirk of the Fragaria genus — the plants produce fisetin as part of a broader flavonoid cocktail that includes anthocyanins (pelargonidin, cyanidin), ellagic acid, quercetin, kaempferol, and vitamin C. Fisetin appears to serve as a UV protectant and antimicrobial in the fruit skin. The concentration is highest in fully ripe fruit and declines during storage; frozen strawberries retain most of their fisetin content, whereas dried and processed strawberry products (jams, preserves) often lose substantial amounts through heat-mediated degradation (3).
From a dietary perspective, strawberries offer more than fisetin. The Basu 2014 evidence review documented that regular strawberry consumption has independent evidence for reductions in inflammatory markers, improvements in vascular function, and modest cardiometabolic benefit (7). This makes strawberries a defensible dietary intervention regardless of the fisetin question. If a reader wanted to prioritise dietary flavonol intake and could add only one fruit to their weekly rotation, strawberries would be the evidence-supported choice.
Dietary intake vs supplement dose — the practical math
Reader questions repeatedly return to the same practical calculation: how much of X food do I need to eat to match a fisetin capsule? The answer is unfortunately impractical.
|
Supplement dose |
Equivalent strawberry intake |
Practical feasibility |
|
100 mg (low daily capsule) |
~625 g strawberries per day |
Achievable for a strawberry-loving reader |
|
500 mg (typical daily capsule) |
~3.1 kg strawberries per day |
Impractical |
|
1,400 mg (pulsed protocol day) |
~8.75 kg strawberries in one day |
Impossible |
|
2,800 mg (full pulsed protocol over 2 days) |
~17.5 kg strawberries over 2 days |
Impossible |
The point is not that eating strawberries is pointless — it is that dietary fisetin intake and supplemental fisetin intake occupy different biological regimes. Dietary intake at 20 to 80 mg per day provides sustained low-concentration flavonoid exposure with the additional context of the fruit matrix (vitamin C, ellagic acid, anthocyanins, fibre). Supplemental intake at 500 to 1,400 mg per day (or per pulse) targets pharmacological concentrations aimed at senolytic activity. Both approaches are defensible. Neither substitutes for the other.
Practical dietary integration
For readers who want to build a fisetin-conscious dietary pattern, the intervention is straightforward and does not conflict with any conventional dietary guidance.
Everyday additions
A 250 g serving of strawberries as a snack, part of breakfast, or a dessert delivers approximately 40 mg fisetin. Frozen strawberries in smoothies work equally well and are less expensive year-round. A medium apple with the skin on delivers approximately 5 mg. Regular grape consumption adds smaller amounts.
The Mediterranean/polyphenol-rich foundation
A dietary pattern that emphasises fruits, vegetables, olive oil, whole grains, and moderate fish intake — the general Mediterranean pattern — delivers not only fisetin but also its structural cousins (quercetin, kaempferol, myricetin), the broader class of anthocyanins, and adequate dietary fat to support flavonoid absorption. This is the most defensible dietary foundation for any reader thinking about longevity, regardless of supplement decisions (4).
When strawberries are out of season
Fresh strawberries in northern latitudes are seasonal. Frozen strawberries retain most of their fisetin content and are a good year-round substitute. Freeze-dried strawberry powder is another option — concentrated per gram but with less fibre and vitamin content than fresh fruit. Strawberry jams and preserves lose substantial fisetin through heat processing and typically carry high added-sugar loads that offset any nutritional benefit.
The epidemiological context
Whether dietary fisetin intake specifically — as opposed to the broader flavonol family or the broader dietary pattern — confers measurable health benefit has not been directly studied in isolation. Fisetin is one of many flavonols, and dietary studies have generally measured intake at the flavonol-class level rather than the individual compound level.
At the flavonol-class level, the evidence is modestly supportive. Higher dietary flavonoid intake has been associated with lower all-cause mortality in multiple large cohort studies (9). Higher flavonol intake specifically has been associated with reduced stroke risk in the Nurses’ Health Study cohort (8). These findings are observational and subject to confounding by overall dietary pattern, but they are consistent with mechanistic expectations from the general antioxidant and anti-inflammatory pharmacology of flavonols.
The fisetin-specific epidemiology does not exist. There has been no cohort study measuring fisetin intake by itself and correlating with outcomes. This is not because fisetin is unimportant — it is because the analytical technology to measure fisetin in complex dietary matrices is expensive and has not been prioritised in nutrition epidemiology.
What we still don't know
• Whether dietary fisetin intake specifically — as opposed to total flavonol intake — correlates with any health outcome in humans. No cohort study has directly measured this.
• Whether the food matrix (fibre, vitamin C, other flavonoids) improves fisetin absorption compared to purified fisetin at the same dose. Preclinical data suggest yes, but human data are absent.
• Whether cooked or processed strawberries retain equivalent fisetin bioavailability. Anecdotal evidence suggests substantial loss with heat processing, but formal measurement is limited.
• Whether a fisetin-rich diet plus a bioavailability-enhanced supplement produces additive benefit. Not studied.
• How much fisetin the average person needs to hit dietary intake associated with reduced disease risk. Threshold effects for flavonol intake and outcomes are not well characterised.
Bottom line
Strawberries are the richest dietary source of fisetin — approximately 40 mg per 250 g serving — with apples, persimmons, grapes, and onions delivering smaller amounts. Dietary intake at the highest achievable food-based level (roughly 80 mg per day for an unusually high strawberry intake) is well below any supplement capsule dose and hundreds-fold below the pulsed protocol trial dose. Dietary intake and supplemental intake occupy different biological regimes and neither substitutes for the other. A strawberry-rich, polyphenol-rich dietary pattern is a defensible foundation for readers thinking about longevity, independent of any supplement decision — the broader flavonol family has genuine cardiovascular and mortality epidemiological evidence. If you take fisetin as a supplement, keep the strawberries too. If you don’t take a supplement, prioritising strawberries and polyphenol-rich foods is a legitimate intervention with independent evidence. Our complete clinician’s guide puts this in the broader context.
Frequently asked questions
What food has the most fisetin?
Strawberries, by a wide margin — approximately 160 μg per gram fresh weight, or about 40 mg in a 250 g serving (1). The next-highest source (apples) contains roughly six times less.
How many strawberries do I need to eat to match a fisetin capsule?
Depends on the capsule. To match a 500 mg daily capsule you would need approximately 3.1 kg of strawberries per day, which is impractical. To match a 100 mg low-dose daily capsule you would need approximately 625 g of strawberries per day, which is achievable but a substantial dietary commitment.
Can I get all my fisetin from food?
For dietary flavonoid intake at nutritionally meaningful levels, yes — 250 g of strawberries daily delivers roughly 40 mg fisetin, well above dietary averages. For supplement-scale doses used in senolytic research, no — the amounts of food required are impractical to eat.
Are frozen strawberries just as good?
Yes, largely. Frozen strawberries retain most of their fisetin content and can be a practical year-round source, particularly for smoothies. Freeze-dried strawberry powder is another concentrated option.
Do strawberry jams and preserves count?
Poorly. Heat processing degrades a substantial portion of the fisetin content, and jams typically carry high added-sugar loads that offset any nutritional benefit. Fresh, frozen, or lightly cooked strawberries are the better sources.
What about strawberry supplements or freeze-dried powders?
Freeze-dried whole-strawberry powders retain most fisetin content and can be a concentrated dietary source — about 30 g of freeze-dried powder is roughly equivalent to 250 g fresh strawberries. Such powders also carry vitamin C, fibre, and other flavonoids in the food matrix. They cost more than fresh strawberries per gram of fisetin delivered, but they are a defensible option for readers who want dietary fisetin without daily strawberry consumption.
References
1. Kimira Y, Osada A, Kimura M, et al. Contents of a bioactive flavonoid fisetin in fruits and vegetables used in the average Japanese diet. J Nutr Sci Vitaminol. 2019;65(5):443-447. https://pubmed.ncbi.nlm.nih.gov/31666481/
2. Arai Y, Watanabe S, Kimira M, et al. Dietary intakes of flavonols, flavones and isoflavones by Japanese women and the inverse correlation between quercetin intake and plasma LDL cholesterol concentration. J Nutr. 2000;130(9):2243-2250. https://pubmed.ncbi.nlm.nih.gov/10958819/
3. Khan N, Syed DN, Ahmad N, Mukhtar H. Fisetin: a dietary antioxidant for health promotion. Antioxid Redox Signal. 2013;19(2):151-162. https://pmc.ncbi.nlm.nih.gov/articles/PMC3689181/
4. Sebastian RS, Wilkinson Enns C, Goldman JD, et al. A new database facilitates characterization of flavonoid intake, sources, and positive associations with diet quality among US adults. J Nutr. 2015;145(6):1239-1248. https://pmc.ncbi.nlm.nih.gov/articles/PMC4442116/
5. Yousefzadeh MJ, Zhu Y, McGowan SJ, et al. Fisetin is a senotherapeutic that extends health and lifespan. EBioMedicine. 2018;36:18-28. https://pmc.ncbi.nlm.nih.gov/articles/PMC6197652/
6. Krishnakumar IM, Jaja-Chimedza A, Joseph A, et al. Enhanced bioavailability and pharmacokinetics of a novel hybrid-hydrogel formulation of fisetin orally administered in healthy individuals. J Nutr Sci. 2022;11:e74. https://doi.org/10.1017/jns.2022.72
7. Basu A, Nguyen A, Betts NM, Lyons TJ. Strawberry as a functional food: an evidence-based review. Crit Rev Food Sci Nutr. 2014;54(6):790-806. https://pubmed.ncbi.nlm.nih.gov/24345049/
8. Cassidy A, Rimm EB, O’Reilly ÉJ, et al. Dietary flavonoids and risk of stroke in women. Stroke. 2012;43(4):946-951. https://pubmed.ncbi.nlm.nih.gov/22363060/
9. Ivey KL, Hodgson JM, Croft KD, et al. Flavonoid intake and all-cause mortality. Am J Clin Nutr. 2015;101(5):1012-1020. https://pubmed.ncbi.nlm.nih.gov/25948669/