Potato or sweet potato: closer than their reputations

Both crops have been tested for how much of their iron the body takes up, though never in the same study. In isotope trials on iron-depleted women, 28.4% of the iron in a regular yellow potato meal was absorbed in Peru against 5.8% from a regular orange sweet potato in Malawi, two separate studies in different countries with different meal sizes, so the gap cannot be put down to the crop alone. The amounts stay small. In 28 young iron-depleted women in the Peruvian highlands, a 16 oz (460 g) meal of regular yellow potato gave 16.6% absorption and about 0.24 mg of absorbed iron. Raw, the two carry similar potassium, 446 to 486 mg per 3.5 oz (100 g) across red, gold and russet potatoes and orange sweet potato in USDA samples. Vitamin C varies more inside the potato family, from 10.9 mg in raw russet to 21 to 23 mg in red and gold, with raw orange sweet potato at 14.8 mg. We found no trial comparing the two head to head on blood sugar or any health outcome.

How much is actually in it

• Raw orange sweet potato and raw white potatoes carry similar potassium, about 446 to 486 mg per 3.5 oz (100 g), in USDA samples. — USDA Foundation Foods, 8 samples each: red, gold, russet potatoes and orange sweet potato, without skin, raw (n = 8 per food) Evidence E source
  Potassium per 3.5 oz (100 g): red potato 472 (427-516), gold 445.8 (342-539), russet 450.1 (407-530), orange sweet potato 486.4 (374-521) mg
• Vitamin C varies more between potato types than between potato and sweet potato: russet averages 10.9 mg per 3.5 oz (100 g) raw, red and gold 21 to 23 mg, orange sweet potato 14.8 mg. — USDA Foundation Foods, 8 samples each, without skin, raw (n = 8 per food) Evidence E source
  Vitamin C per 3.5 oz (100 g): red 21.29 (14.2-29.6), gold 23.3 (16.6-30.3), russet 10.9 (7.44-19.8), orange sweet potato 14.84 (13.0-17.5) mg

What a real portion looks like

• US survey coding sets a medium baked potato at 285 g and about 265 calories, and a medium sweet potato at 150 g and about 173 calories. — Potato, baked, NFS (FNDDS 71100100) and Sweet potato, NFS (FNDDS 73401000) Evidence E source
  Per 100 g: potato 93 calories, sweet potato 115 calories; medium item: 265.1 vs 172.5 calories

What your body absorbs

• In two separate isotope trials, iron-depleted women in Peru absorbed 28.4% of iron from regular yellow potato and women in Malawi 5.8% from regular orange sweet potato. — Iron-depleted women of reproductive age: 24 in Malawi (sweet potato, 14 oz (400 g) meals), 35 in Peru (potato, 18 oz (500 g) meals), 2 weeks per variety (n = 59) Evidence B source
  Fractional iron absorption: sweet potato 5.82% (3.79-8.95), yellow potato 28.4% (23.5-34.2)
• In a crossover RCT on 28 iron-depleted women, a 460 g potato meal delivered about 0.24 mg absorbed iron from a regular yellow potato, with 16.6% fractional absorption. — Women aged 18-25 in the Peruvian highlands, plasma ferritin about 21 ug/L, 10 meals of each potato (n = 28) Evidence B source
  Fractional absorption 16.6% (14.0-19.6) regular vs 12.1% biofortified; total absorbed 0.24 vs 0.35 mg per meal
• In a crossover RCT on 37 women, about a quarter of the zinc in regular boiled potatoes was absorbed, 25.5%, giving 0.40 mg per 500 g. — Women in the Peruvian highlands eating 18 oz (500 g) potatoes (n = 37) Evidence B source
  Fractional zinc absorption 25.5% (SD 7.0) regular vs 20.8% biofortified; total 0.40 vs 0.49 mg per 500 g

What cooking and storage change

• In three US cohorts of 205,107 people, each 3 weekly servings of French fries were linked to a 20% higher type 2 diabetes rate, while baked, boiled or mashed potatoes were not. — US adults in NHS, NHSII and HPFS, free of diabetes at baseline, followed up to 36 years (n = 205107) Evidence C source
  HR 1.20 (1.12-1.28) per 3 servings/week of French fries; baked, boiled, mashed HR 1.01 (0.98-1.05)
• In seven pooled cohorts of 110,063 adults, eating 5 or more potato servings a week was not linked to CVD, but 1 or more weekly servings of fried potatoes went with 10% higher hypertension risk. — Adults aged 25-72 in ARIC, CARDIA, COSMOS, MESA, WACS, WHS, PHS (n = 110063) Evidence C source
  CVD HR 0.96 (0.89-1.04) for 5+ servings/week; hypertension +10% (4% to 17%) with fried potatoes

What it does to your health

• A meta-analysis of 103 observational studies found total potato intake unrelated to hypertension, CVD or stroke, while fried potatoes were linked to 16% higher diabetes risk. — 51 articles, 103 observational studies Evidence C source
  Total potato: hypertension RR 1.07 (0.95-1.21), CVD 0.97 (0.91-1.03); fried potato and diabetes RR 1.16 (1.04-1.30)
• In the EPIC cohort of 341,519 Europeans, the highest potato intake quartile was linked to 51% higher risk of ulcerative colitis. — European adults followed a median 13.4 years, 379 UC cases (n = 341519) Evidence C source
  UC aHR 1.51 (1.05-2.17), fourth vs first quartile

What people believe that the data does not support

• The Nordic Nutrition Recommendations 2023 review found moderate potato intake not linked to substantial chronic disease risk, while French fries should be limited. — Systematic reviews and meta-analyses on potatoes, Nordic and Baltic context Evidence C source
  No substantial risk with moderate intake; limit fried potatoes
• The EU refused a claim that a potato extract reduces body weight in overweight people. — EU Register on nutrition and health claims Evidence E source
  Claim status non-authorized
• The EU refused claims that potato protein isolate increases satiety, reduces appetite or supports weight control. — EU Register on nutrition and health claims Evidence E source
  Claim status non-authorized

Who this works differently for

• A meta-analysis of 29,288 pregnancies linked each daily 2.8 oz (80 g) serving of potato with 22% higher gestational diabetes risk. — Pregnant women in 6 studies, 1516 GDM cases (n = 29288) Evidence C source
  GDM RR 1.22 (1.06-1.42) per 80 g/day of total potato; unfried RR 1.26 (1.07-1.48)
• A systematic review of 20 studies in Mozambique found that orange-fleshed sweet potato introduction improved vitamin A status in women and children. — Women and children in Mozambique, 20 studies Evidence C source
  Positive impact on vitamin A status reported; size not given in abstract

What is still unknown

• Baking potatoes in their skin keeps about 80% of vitamin C and all of the potassium by the USDA retention table, which lists no factor for carotenoids. — Vegetables and Vegetable Products group, potatoes baked in skin (USDA R6 code 3301) Evidence E source
  Retained: vitamin C 80%, thiamin 85%, folate 90%, vitamin B6 95%, potassium 100%

The bottom line

A medium baked potato is coded at 285 g and about 265 calories in US survey data, and a medium sweet potato at 150 g and about 173 calories, both recalculated from 100 g values. Per 100 g the sweet potato carries more energy, 115 against 93 calories, so the gap comes from size. Baking a potato in its skin keeps about 80% of its vitamin C and all of its potassium by the USDA retention table, a 1975 table with no factor for carotenoids and no code of its own for sweet potato. In 37 women in the Peruvian highlands, 25.5% of the zinc in 18 oz (500 g) of regular boiled potatoes was absorbed, about 0.40 mg. For ordinary potatoes, the cooking method shows up in the data more than the potato does. In three US cohorts of 205,107 adults followed up to 36 years, each extra 3 servings a week of French fries went with a 20% higher type 2 diabetes rate (HR 1.20, 95% CI 1.12 to 1.28). Baked, boiled or mashed potatoes showed no link (HR 1.01, 0.98 to 1.05), and total potato went with 5% higher. A meta-analysis of 103 observational studies found total potato unrelated to hypertension (RR 1.07, 0.95 to 1.21) or cardiovascular disease (RR 0.97, 0.91 to 1.03), while fried potato went with 16% higher diabetes risk (RR 1.16, 1.04 to 1.30). Seven pooled cohorts of 110,063 adults tied 1 or more weekly servings of fried potato to 10% higher hypertension risk (4% to 17%). All of this is observational, so it shows association and cannot show cause. The Nordic Nutrition Recommendations 2023 review, working from evidence it calls very limited, found no substantial chronic disease risk from moderate intake and advised limiting French fries. In the European EPIC cohort of 341,519 adults, the highest quarter of potato intake went with 51% higher risk of ulcerative colitis (HR 1.51, 1.05 to 2.17), from only 379 cases and with preparation not separated. We found no study of sweet potato and chronic disease. The one sweet potato outcome we have comes from a different setting: a review of 20 studies in Mozambique found that bringing in orange-fleshed sweet potato improved vitamin A status in women and children, without giving a size for the effect. The EU has refused a claim that a potato extract reduces body weight in overweight people, and claims that potato protein isolate increases satiety or supports weight control. This page has no card on safety, allergy or drug interactions for either crop. The one finding about a specific group is pregnancy. A meta-analysis of 6 studies covering 29,288 pregnancies linked each daily 2.8 oz (80 g) serving of potato with 22% higher gestational diabetes risk (RR 1.22, 95% CI 1.06 to 1.42), from few studies and observational data. A larger 2025 meta-analysis found no gestational diabetes link for fried potato (RR 1.03, 0.97 to 1.09), a different exposure from total potato, and neither can show cause.

Sources

1. pvs-r3-01 · reference dataset
   Potatoes, red, without skin, raw: Potassium, K 472.0 MG (range 427.0-516.0, 8 samples); Potatoes, gold, without skin, raw: 445.8 MG (342.0-539.0, 8); Potatoes, russet, without skin, raw: 450.1 MG (407.0-530.0, 8); Sweet potatoes, orange flesh, without skin, raw: 486.4 MG (374.0-521.0, 8)
   USDA FoodData Central, Foundation Foods, release 2026-04-30 · checked 2026-10-02
2. pvs-r3-02 · reference dataset
   Potatoes, red, without skin, raw: Vitamin C 21.29 MG (range 14.2-29.6, 8 samples); Potatoes, gold, without skin, raw: 23.3 MG (16.6-30.3, 8); Potatoes, russet, without skin, raw: 10.9 MG (7.44-19.8, 8); Sweet potatoes, orange flesh, without skin, raw: 14.84 MG (13.0-17.5, 8)
   USDA FoodData Central, Foundation Foods, release 2026-04-30 · checked 2026-10-02
3. pvs-r3-04 · reference dataset
   Potato, baked, NFS (fdc_id 2709383): Energy 93 KCAL per 100 g; 1 medium 285 g 265.1 KCAL; Sweet potato, NFS (fdc_id 2709697): Energy 115 KCAL per 100 g; 1 medium 150 g 172.5 KCAL
   USDA FNDDS, FoodData Central survey foods, fdc_id 2709383 and 2709697 · checked 2026-10-02
4. pvs-r3-05 · RCT
   Geometric mean (95% CI) fractional iron absorption (FIA) was 5.82% (3.79%, 8.95%) and 6.02% (4.51%, 8.05%), respectively (P = 0.81), resulting in 1.9-fold higher total iron absorption (TIA) from biofortified sweetpotato (P < 0.001). The regular and biofortified potato test meals contained 0.33 and 0.69 mg Fe/100 g. FIA was 28.4% (23.5%, 34.2%) from the regular yellow-fleshed and 13.3% (10.6%, 16.6%) from the biofortified purple-fleshed potato meals
   J Nutr, 2020 · checked 2026-10-02
5. pvs-r3-06 · RCT
   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 2026-10-02
6. pvs-r3-07 · RCT
   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 2026-10-02
7. pvs-r3-08 · cohort
   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 2026-10-02
8. pvs-r3-10 · cohort meta-analysis
   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 2026-10-02
9. pvs-r3-09 · 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)
   Nutr Rev, 2025 · checked 2026-10-02
10. pvs-r3-12 · cohort
    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 2026-10-02
11. pvs-r3-14 · scoping review
    Current available evidence indicates that moderate consumption of potatoes is not associated with a substantial risk of chronic diseases, and that they may be part of a healthy diet. However, the health effects vary greatly depending on cooking methods, and studies indicate that the intake of French fries/fried potatoes should be limited.
    Food Nutr Res, 2024 · checked 2026-10-02
12. pvs-r3-15 · registry entry
    POL-HC-8425 Slendesta® Potato Extract Slendesta® contributes to the reduction of body weight in overweight individuals -/- Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-8425, snapshot 2026-09-21 · checked 2026-10-02
13. pvs-r3-16 · registry 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 2026-10-02
14. pvs-r3-11 · meta-analysis
    In the dose-response meta-analysis, a significantly increased GDM risk was revealed for each daily serving (80 g) intakes of total potato (RR: 1.22; 95% CI: 1.06, 1.42; P for trend = 0.007) and unfried potato (RR: 1.26; 95% CI: 1.07, 1.48; P for trend = 0.006).
    Clin Nutr, 2021 · checked 2026-10-02
15. pvs-r3-13 · systematic review
    Orange-fleshed sweet potatoes are widely accepted by Mozambican farmers and consumers, and various studies show a positive impact on vitamin A status due to the introduction of this nutritionally superior staple crop.
    Food Nutr Bull, 2015 · checked 2026-10-02
16. pvs-r3-03 · reference dataset
    USDA-RETN-R6:3301 POTATOES,BAKED IN SKIN - vitamin_c_mg 80% - thiamin_mg 85% - folate_total_ug 90% - vitamin_b6_mg 95% - potassium_mg 100%
    USDA Table of Nutrient Retention Factors, Release 6 (2007), code 3301 · checked 2026-10-02