Banana or potato: the one strong answer here is about toddlers

The strongest evidence on either of these foods was not collected in people like you. A meta-analysis of nine randomized trials in 3996 children aged 8 to 34 months found that adding green banana to standard treatment nearly doubled the rate at which diarrhea resolved (HR 1.96, 95% CI 1.62 to 2.37). The effect was larger in persistent diarrhea at 2.34 than in acute diarrhea at 1.74. Seven of those nine trials were open, with nobody blinded, and every participant was a young child, which the authors state plainly. The arm those children were compared against was standard treatment alone, so the banana was an addition to care and not a replacement for it. Everything else about this pair comes from watching people eat, with one exception: two randomized isotope trials in Peruvian women measured how much iron and zinc a potato meal actually delivers. Per 100 g raw, potato carries about twice the vitamin C of banana, 21.29 mg against 9.7 mg, along with 472 mg of potassium. That comparison is shakier than it looks. The two USDA records behind those numbers are overripe banana and red potato without skin, and the United Kingdom table puts the same two foods lower, at 5 mg and 14 mg of vitamin C. Potassium in potato runs from 144 to 1848 mg across 86 USDA records, and from 342 to 539 mg across the eight Foundation samples, so the spread inside potato is wider than the gap between potato and banana.

How much is actually in it

• Per 100 g raw, potato carries about twice the vitamin C of banana, 21.29 mg against 9.7 mg, and 472 mg of potassium, while the potato figure swings from 144 to 1848 mg across 86 USDA records. — USDA reference records and UK CoFID records for the two foods, not a measurement in people Evidence E source
  Banana vitamin C 9.7 mg, vitamin B6 0.234 mg per 3.5 oz (100 g); potato vitamin C 21.29 mg, potassium 472 mg, copper 0.091 mg per 3.5 oz (100 g); potato potassium range 144 to 1848 mg over 86 records and 342 to 539 mg over 8 Foundation samples

What your body absorbs

• In 28 Peruvian women fed ten 460 g potato meals, 12.1 percent of the iron in biofortified potato was absorbed against 16.6 percent from the ordinary variety, yet the total iron absorbed was higher at 0.35 mg per meal against 0.24 mg. — 28 women aged 18 to 25 with low iron stores, ten consecutive 460 g potato meals, absorption read from erythrocytes 14 days later (n = 28) Evidence B source
  Fractional absorption 12.1% (95% CI 10.3 to 14.2) versus 16.6% (95% CI 14.0 to 19.6), total absorbed 0.35 mg (0.30 to 0.41) versus 0.24 mg (0.20 to 0.28) per 460 g meal, P < 0.001
• In 37 Peruvian women fed 18 oz (500 g) of boiled potato twice a day, 20.8 percent of the zinc in biofortified potato was absorbed against 25.5 percent from the regular variety, while the total zinc absorbed was higher at 0.49 mg against 0.40 mg. — 37 women aged 18 to 45, 500 g boiled potato meals twice a day, absorption read from urine, washout 30 days (n = 37) Evidence B source
  Fractional zinc absorption 20.8% (SD 5.4) versus 25.5% (SD 7.0), total absorbed 0.49 mg (SD 0.13) versus 0.40 mg (SD 0.11) per 500 g, P < 0.01

What cooking and storage change

• In 205,107 US adults, three extra weekly servings of French fries went with a 20 percent higher rate of type 2 diabetes (HR 1.20, 95% CI 1.12 to 1.28). Baked, boiled or mashed potatoes showed no association (HR 1.01, 95% CI 0.98 to 1.05). — 205,107 US nurses and health professionals free of diabetes at baseline, 5,175,501 person years, 22,299 cases, plus a meta-analysis of 13 cohorts with 587,081 people (n = 205107) Evidence C source
  Total potato HR 1.05 (95% CI 1.02 to 1.08) and French fries HR 1.20 (1.12 to 1.28) per three servings weekly, baked or boiled or mashed HR 1.01 (0.98 to 1.05), replacing three servings of French fries with whole grains estimated 19 percent lower risk (14 to 25)
• Across seven harmonized prospective cohorts with 110,063 adults, fried potato intake was not associated with cardiovascular disease, while one or more servings a week carried a 10 percent higher risk of hypertension (95% CI 4 to 17 percent). — 110,063 adults for cardiovascular outcomes and 67,146 for hypertension, mean age 25 to 72 years, 65 percent women, usual intake 1.9 to 4.3 potato servings a week (n = 110063) Evidence C source
  Fried potato 1+ servings a week versus none, no association with cardiovascular disease and 10 percent higher risk of hypertension (95% CI 4 to 17 percent), from 7 cohorts for cardiovascular disease (n = 110,063) and 5 for hypertension (n = 67,146)

What it does to your health

• A synthesis of 51 articles covering 103 observational studies found fried potato intake associated with a 16 percent higher diabetes risk (RR 1.16, 95% CI 1.04 to 1.30). Nonfried potato carried a 5 percent higher diabetes risk (RR 1.05, 1.01 to 1.10) and no association with hypertension (RR 1.06, 0.97 to 1.15). — 51 articles covering 103 observational studies, highest versus lowest intake categories (n = 103 studies) Evidence C source
  Fried potato and diabetes RR 1.16 (95% CI 1.04 to 1.30), nonfried potato and diabetes RR 1.05 (1.01 to 1.10), nonfried potato and hypertension RR 1.06 (0.97 to 1.15), fried potato and overweight or obesity RR 1.24 (0.90 to 1.70), fried potato and gestational diabetes RR 1.03 (0.97 to 1.09)

Safety, limits and interactions

• NIH Office of Dietary Supplements states that in people whose kidneys cannot clear potassium, because of chronic kidney disease or of ACE inhibitors and potassium-sparing diuretics, even potassium intakes below the Adequate Intake can cause hyperkalemia. — adults with chronic kidney disease or taking ACE inhibitors or potassium-sparing diuretics Evidence E source
  Hyperkalemia possible below the Adequate Intake, no threshold given

What people believe that the data does not support

• The EU refused the claim that banana is a major dietary source of antioxidants protecting cells from oxidative damage, so that wording cannot be used on a label in the EU. — EU food labeling, general population Evidence E source
  Claim refused, no authorized antioxidant wording exists for banana
• The EU also refused the satiety and appetite claims for potato protein isolate, so the idea that potato keeps you full longer has no authorized wording in the EU. — EU food labeling, general population Evidence E source
  Claim refused, no authorized satiety wording exists for potato protein

Who this works differently for

• A meta-analysis of nine randomized trials in 3996 children aged 8 to 34 months found that adding green banana to standard treatment nearly doubled the rate of diarrhea resolution (HR 1.96, 95% CI 1.62 to 2.37). — 3996 children aged 8 to 34 months with acute or persistent diarrhea, green banana added to standard treatment (n = 3996) Evidence A source
  HR 1.96 (95% CI 1.62 to 2.37) for resolution overall, 2.34 (1.78 to 3.08) in persistent diarrhea and 1.74 (1.45 to 2.09) in acute diarrhea, I2 52 percent
• In 341,519 Europeans followed a median 13.4 years, pooled consumption of apple or pear, banana, mushrooms and onion or garlic was associated with a lower risk of Crohn disease (aHR 0.58, 95% CI 0.33 to 1.02). That interval crosses 1. The top quartile of potato intake carried a 51 percent higher risk of ulcerative colitis (aHR 1.51, 95% CI 1.05 to 2.17), on 149 Crohn and 379 ulcerative colitis cases. — 341,519 adults in the EPIC cohort, median follow-up 13.4 years, 149 cases of Crohn disease and 379 of ulcerative colitis (n = 341519) Evidence C source
  Apple or pear, banana, mushrooms and onion or garlic pooled, fourth versus first quartile, Crohn aHR 0.58 (95% CI 0.33 to 1.02, P trend 0.03); potato fourth versus first quartile, ulcerative colitis aHR 1.51 (95% CI 1.05 to 2.17); 149 Crohn and 379 ulcerative colitis cases

What is still unknown

• The USDA retention table gives potato 16 named cooking methods and keeps 80 percent of its vitamin C and all of its potassium and copper when baked in the skin, while banana is not named in the table at all. — USDA retention factors set on food group and cooking method, not on a single cultivar Evidence E source
  Potato baked in skin (code 3301) and baked in casserole (code 3302): vitamin C 80 percent retained, copper 100 percent, potassium 100 percent; 16 potato methods in total including boiled, fried, mashed and French fry from frozen; banana has no entry of its own

The bottom line

The division that shows up in the data runs between fried potato and everything else. In 205,107 United States nurses and health professionals followed over 5.1 million person years, three extra weekly servings of French fries went with a 20 percent higher rate of type 2 diabetes (HR 1.20, 95% CI 1.12 to 1.28). Baked, boiled or mashed potatoes showed no association (HR 1.01, 95% CI 0.98 to 1.05). Those are observed eating habits and not a trial. The people eating the most potato were also less active and ate worse in other ways, and the authors accept that residual confounding remains. A synthesis of 51 articles covering 103 observational studies puts fried potato and diabetes at RR 1.16 (95% CI 1.04 to 1.30) and nonfried potato at RR 1.05 (1.01 to 1.10), and finds no association between nonfried potato and hypertension (RR 1.06, 95% CI 0.97 to 1.15). Seven harmonized cohorts with 110,063 adults land in the same place, where fried potato at one or more servings a week carried a 10 percent higher risk of hypertension (95% CI 4 to 17 percent) while showing no association with cardiovascular disease. Two isotope trials in Peru show something counterintuitive about the minerals in potato. In 28 women aged 18 to 25 with low iron stores, fed ten consecutive 460 g potato meals, only 12.1 percent of the iron in a biofortified variety was absorbed against 16.6 percent from the ordinary one. The biofortified meal still delivered more iron in total, 0.35 mg against 0.24 mg. Zinc behaved the same way in 37 women eating 18 oz (500 g) of boiled potato twice a day, at 20.8 percent absorbed against 25.5 percent and 0.49 mg delivered against 0.40 mg. The percentage and the milligrams move in opposite directions because the two varieties differ in phytate, and both trials used varieties bred for the experiment rather than anything on a shop shelf. Cooking is documented for potato and not for banana. The USDA retention table lists 16 cooking methods for potato and gives baking in the skin 80 percent retention of vitamin C with all of the potassium and copper kept, while banana is not named in that table at all. The caution belongs to both foods and to one group of readers. The NIH Office of Dietary Supplements states that in people who cannot clear potassium, because of chronic kidney disease or of ACE inhibitors and potassium-sparing diuretics, even intakes below the Adequate Intake can cause hyperkalemia, and it names no threshold in grams. Potato at 472 mg per 3.5 oz (100 g) is squarely a potassium food, so for that group the choice between these two has a medical answer and not only a culinary one. In 341,519 Europeans followed a median 13.4 years, the top quartile of potato intake went with a higher rate of ulcerative colitis (aHR 1.51, 95% CI 1.05 to 2.17) on 379 cases. Banana in that study was pooled with apple or pear, mushrooms and onion or garlic, and the pooled figure for Crohn disease (aHR 0.58, 95% CI 0.33 to 1.02) did not reach significance, so nothing in it can be pinned on banana by itself. Europe refused the claim that banana is a major dietary source of antioxidants, and refused the satiety claims made for potato protein isolate, which is an ingredient rather than a potato on a plate. No study we found compares the two foods head to head as replacements for each other, and none tested fried potato below three servings a week.

Sources

1. bnpt-daily-r5-08 · USDA FoodData Central and CoFID, datasets
   USDA-FDC:1105073 Bananas, overripe, raw, Foundation, group Fruits and Fruit Juices: vitamin C 9.7 mg, vitamin B6 0.234 mg per 100 g, Foundation samples n=12; USDA-FDC:2346402 Potatoes, red, without skin, raw, Foundation, group Vegetables and Vegetable Products: vitamin C 21.29 mg, potassium 472 mg, copper 0.091 mg per 100 g, 86 records range 144-1848 mg potassium, Foundation samples n=8 range 342-539 mg; CoFID-2021:14-347 Bananas, raw, flesh only: vitamin C 5 mg, vitamin B6 0.2 mg; CoFID-2021:13-489 Potatoes, old, raw, flesh only: vitamin C 14 mg, potassium 443 mg, copper 0.06 mg
   USDA FoodData Central FDC 1105073 and FDC 2346402 (Foundation Foods) with CoFID 2021, Public Health England, codes 14-347 and 13-489, OGL v3.0 · checked 2026-09-25
2. bnpt-daily-r5-01 · stable isotope absorption trial
   We conducted a single-blinded, randomized, crossover, multiple-meal intervention study. Women (n = 28; mean ± SD plasma ferritin 21.3 ± 3.3 μg/L) consumed 10 meals (460 g) of both potatoes, each meal extrinsically labeled with either 58Fe sulfate (biofortified) or 57Fe sulfate (nonfortified), on consecutive days. ... Geometric mean (95% CI) fractional iron absorption from the iron-biofortified clone and the nonbiofortified variety were 12.1% (10.3%-14.2%) and 16.6% (14.0%-19.6%), respectively (P < 0.001). Total iron absorption from the iron-biofortified clone and the nonbiofortified variety were 0.35 mg (0.30-0.41 mg) and 0.24 mg (0.20-0.28 mg) per 460 g meal, respectively (P < 0.001).
   J Nutr, 2023 · checked 2026-09-25
3. bnpt-daily-r5-02 · stable isotope absorption trial
   We undertook a single-blinded randomized crossover study (using 67Zn and 70Zn stable isotopes) in which 37 women consumed 500-g biofortified or regular potatoes twice a day. ... Mean fractional zinc absorption (FZA) from the biofortified potatoes was lower than from the regular potatoes, 20.8% (SD: 5.4%) and 25.5% (SD: 7.0%), respectively (P < 0.01). However, total zinc absorbed was significantly higher (0.49; SD: 0.13 and 0.40; SD: 0.11 mg/500 g, P < 0.01, respectively).
   J Nutr, 2023 · checked 2026-09-25
4. bnpt-daily-r5-03 · cohort study and substitution meta-analysis
   For every increment of three servings weekly of total potato, the rate for T2D increased by 5% (hazard ratio 1.05, 95% confidence interval (CI) 1.02 to 1.08) and for every increment of three servings weekly of French fries the rate increased by 20% (1.20, 1.12 to 1.28). Intake of combined baked, boiled, or mashed potatoes was not significantly associated with T2D risk (pooled hazard ratio 1.01, 95% CI 0.98 to 1.05).
   BMJ, 2025 · checked 2026-09-25
5. bnpt-daily-r5-05 · pooled cohort analysis
   We conducted a meta-analysis using data from seven cohorts for CVD (n = 110,063) and five cohorts for HTN (n = 67,146). ... while fried potato consumption was not associated with CVD risk, there was a 10% higher risk of HTN (95% CI: 4% to 17%) comparing 1+ servings/week to no fried potato intake.
   Nutrients, 2025 · checked 2026-09-25
6. bnpt-daily-r5-04 · meta-analysis of observational studies
   Fifty-one articles (103 studies) were identified in the current meta-analysis. ... fried potato intake was not associated with overweight/obesity (1.24; 95% CI: 0.90, 1.70) or GDM (1.03; 95% CI: 0.97, 1.09) but was significantly associated with increased diabetes risk (1.16; 95% CI: 1.04, 1.30); nonfried potato intake was significantly associated with increased diabetes risk (1.05; 95% CI: 1.01, 1.10) but not hypertension (1.06; 95% CI: 0.97, 1.15).
   Nutr Rev, 2025 · checked 2026-09-25
7. bnpt-daily-r5-12 · agency fact sheet
   However, in people with impaired urinary potassium excretion due to chronic kidney disease or the use of certain medications, such as angiotensin converting enzyme (ACE) inhibitors or potassium-sparing diuretics, even dietary potassium intakes below the AI can cause hyperkalemia.
   NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals · checked 2026-09-25
8. bnpt-daily-r5-10 · claim register entry
   POL-HC-6676 Banana Banana is a major dietary source of antioxidants Antioxidants from dietary sources contribute to the protection against free radicals which cause cell damage Contributes to the protection of cells and tissues from oxidative damage Help strengthen our body's natural defences against oxidative stress Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-6676, snapshot 2026-09-21 · checked 2026-09-25
9. bnpt-daily-r5-11 · claim register entry
   POL-HC-7796 Potato protein isolate Increases the sense of satiety Elicit satiety Reduces appetite Supports weight control Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-7796, snapshot 2026-09-21 · checked 2026-09-25
10. bnpt-daily-r5-06 · meta-analysis of randomized trials
    Nine randomized controlled trials (seven open and two blinded) were included. Studies were conducted in the pediatric population comprising a total of 3996 patients aged 8 to 34 months, eight studies were written in English and one in Spanish. GB-based food consumption significantly increased the hazard of resolution of diarrhea compared to standard treatment (HR 1.96, 95% CI [1.62; 2.37], p < 0.01; I2 = 52%).
    Eur J Pediatr, 2024 · checked 2026-09-25
11. bnpt-daily-r5-07 · prospective cohort
    In total, 341,519 individuals were followed prospectively. Among them, 149 developed CD and 379 developed UC after a median follow-up of 13.4 years. ... Pooled consumption of apple/pear, banana, mushrooms, and onion/garlic was associated with a lower risk of CD (fourth vs first quartile aHR 0.58; 95% CI: 0.33-1.02, P trend 0.03). A higher risk of UC was observed with high intakes of potatoes (fourth vs first quartile aHR 1.51; 95% CI: 1.05-2.17).
    Am J Gastroenterol, 2026 · checked 2026-09-25
12. bnpt-daily-r5-09 · USDA Table of Nutrient Retention Factors, dataset
    USDA-RETN-R6:3301 POTATOES,BAKED IN SKIN, group Vegetables and Vegetable Products: vitamin_c_mg 80% retained, copper_mg 100%, potassium_mg 100%; USDA-RETN-R6:3302 POTATOES,BAKED IN CASSEROLE: vitamin_c_mg 80% retained, copper_mg 100%, potassium_mg 100%; 16 potato methods listed including 3307 BOILED IN SKIN, 3315 FRIED, 3316 MASHED, 3381 CKD FROM FRZN,FRENCH FRY; no banana entry in Release 6
    USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Codes 3301 and 3302, group Vegetables and Vegetable Products · checked 2026-09-25