Cucumber and pumpkin leaves: the control-group vegetable and a leaf with one study

Cucumber turns up in nutrition trials mostly as the food given to the comparison group. In a cluster trial of 399 Indian preschoolers aged 24 to 48 months, 25 g of guava added to meals for 140 days raised hemoglobin and ferritin compared with the same amount of banana or cucumber. The abstract gives significance levels and no effect sizes. In 38 adults with prediabetes, a small daily dose of a freeze-dried, cucumber-based control supplement left fasting glucose unchanged over 12 weeks, which tells you little about cucumber eaten as a vegetable. By the numbers, cucumber is mostly water: UK food tables give 96.5 g water and 14 calories per 3.5 oz (100 g). Pumpkin leaves have even less behind them. One cross-sectional study of 2947 school students aged 10 to 18 in Burkina Faso linked eating them with lower odds of anemia (aOR 0.77, 95% CI 0.605 to 0.974). That is an association, and it cannot show that the leaves were the reason.

How much is actually in it

• Raw cucumber with peel holds about 170 mg potassium and 24 ug vitamin K per 3.5 oz (100 g), and potassium varied from 136 to 211 mg across 8 USDA samples. — USDA Foundation Foods, Cucumber, with peel, raw, 8 samples (n = 8 samples) Evidence E source
  Potassium 169.6 mg/100 g (136-211); vitamin K1 24.0 ug/100 g (16.0-32.2)
• UK food tables give raw cucumber 14 calories and 96.5 g water per 3.5 oz (100 g), with 0.7 g fiber. — CoFID 2021, Cucumber, raw, flesh and skin (n = 1 food) Evidence E source
  Energy 14 calories; water 96.5 g; AOAC fiber 0.7 g; total sugars 1.2 g per 3.5 oz (100 g)

What a real portion looks like

• US survey coding counts a cup of sliced cucumber as 120 g and a whole regular cucumber as 200 g. — USDA FNDDS portion measures, Cucumber, raw (n = 6 measures) Evidence E source
  1 cup 120 g; 1 regular 200 g; 1 miniature 65 g; 1 slice 10 g
• School children aged 8 to 13 ate 54% more cucumber (49 g) when served a larger portion as a snack. — 255 primary-school pupils aged 8-13, Netherlands (n = 255) Evidence C source
  +54% intake, difference 49 g (P < 0.001)

What your body absorbs

• In a lab study of pumpkin leaves, boiling cut oxalate by about 82% and phytate from 81 to 17 mg/g, while steaming kept most of both. — young Cucurbita maxima leaves, laboratory cooking comparison Evidence D source
  Oxalate 85.46 to 15.56 mg/g after boiling; phytate 81.05 to 16.62 mg/g
• In a 140-day cluster trial in Indian preschoolers, adding 0.88 oz (25 g) of guava to meals improved iron status more than the same amount of banana or cucumber. — 399 children aged 24-48 months, 28 preschools, India, 140 days (n = 399) Evidence B source
  Higher hemoglobin (P = 0.002) and ferritin (P < 0.001) in guava group vs banana and cucumber groups

What cooking and storage change

• By the USDA retention table for vegetable greens boiled in water and drained, about 55% of vitamin C and 60% of folate stay in the leaves. — USDA retention factors, Vegetables and Vegetable Products, greens boiled, water cover, drained Evidence E source
  Vitamin C 55% retained; folate 60%; potassium 85%; calcium and iron 95%

What it does to your health

• In a 30-day pilot trial in people over 60, daily cucumber powder raised plasma vitamin C and glutathione peroxidase, much like lotus root did. — healthy adults over 60, 30 days, cucumber or lotus root powder (n = 25) Evidence C source
  Plasma GPx, vitamin C and total phenolics increased within both groups
• Observational data from Burkina Faso link eating pumpkin leaves with lower odds of anemia in adolescents (aOR 0.77). — 2947 school students aged 10-18, Burkina Faso (n = 2947) Evidence C source
  AOR 0.77 (95% CI 0.605 to 0.974)

Safety, limits and interactions

• In a hepatitis E outbreak in China, eating cucumber in sauce was linked to infection (aOR 4.44) after pans for raw pork were reused for cold dishes. — 80 exposed people at a funeral dinner, Yantai, China (n = 80) Evidence C source
  AOR 4.44 (95% CI 1.23 to 16.06)
• Bitter-tasting cucurbits can carry cucurbitacin: a case report of poisoning from a garden-grown cucurbit says a bitter taste is essential to recognizing it. — one 66-year-old woman (n = 1) Evidence C source
  Hemorrhagic colitis, recovered in 2 days
• A pooled analysis of pesticide residues in Iranian foods ranked cucumber highest for attributable disease burden (5.9 DALY rate). — residue studies of foodstuffs in Iran Evidence C source
  Cucumber DALY rate 5.9, fish 3.9, date 2.1

What people believe that the data does not support

• In a 12-week trial in people with prediabetes, a cucumber-based control supplement left fasting glucose unchanged. — 38 adults with prediabetes, 12 weeks, freeze-dried supplement (n = 38) Evidence B source
  Fasting glucose unchanged on cucumber control; bitter gourd -0.9 mg/dL (-0.05 mmol/L) per week

Who this works differently for

• When UK nurseries offered cucumber sticks and carrot batons at breakfast for three weeks, children ate some of them in 62% of offers. — 351 children in eight UK nurseries, three weeks (n = 351) Evidence B source
  Vegetables eaten in 62.4% (745/1194) of offers

What is still unknown

• US survey data have no separate entry for pumpkin leaves: a combined cooked leaves entry gives 154 ug vitamin A (RAE) per 3.5 oz (100 g), about 106 ug in a 69 g cup. — USDA FNDDS, Sweet potato, squash, pumpkin, chrysanthemum, or bean leaves, cooked (n = 1 food) Evidence E source
  Vitamin A 154 ug RAE/100 g, 106.3 ug per cup; calcium 32 mg/100 g, 22.1 mg per cup

The bottom line

Raw cucumber with peel holds about 170 mg potassium per 3.5 oz (100 g), ranging from 136 to 211 mg across 8 USDA samples, and 24 ug vitamin K. Peeling lowers the vitamin K by an amount those samples did not measure. US survey coding counts a cup of slices as 120 g and a whole regular cucumber as 200 g. On a single snack occasion with 255 Dutch pupils aged 8 to 13, a larger portion raised the cucumber eaten by 54%, or 49 g. In eight UK nurseries over three weeks, 351 children ate some of the cucumber sticks and carrot batons offered at breakfast in 62% of offers, a feasibility count with no grams recorded. In a 30-day pilot in healthy adults over 60, 12.5 g a day of cucumber powder raised plasma vitamin C and glutathione peroxidase. Lotus root powder did the same, and there was no untreated group to compare against. US survey data have no entry for pumpkin leaves alone. A pooled entry for cooked sweet potato, squash, pumpkin, chrysanthemum or bean leaves gives 154 ug vitamin A (RAE) per 3.5 oz (100 g), about 106 ug in a 69 g cup. In a lab study of young leaves from one pumpkin cultivar, boiling cut oxalate by about 82% and phytate from 81 to 17 mg/g. Nobody in that study measured what this means for absorption in people. The USDA retention factor for greens boiled and drained, a group figure from 1975 never measured on pumpkin leaves, keeps about 55% of vitamin C and 60% of folate. The cautions here are indirect. At a funeral dinner in China where 80 people were exposed to hepatitis E, eating cucumber in sauce was linked to infection (aOR 4.44, 95% CI 1.23 to 16.06), and the likely route was cross-contamination in the kitchen. A bitter taste in any cucurbit is a warning sign. One case report of cucurbitacin poisoning from a garden-grown cucurbit says bitterness is how the poisoning is recognized, and we found no such report for cucumber. A pooled analysis of residue studies in Iran ranked cucumber first for modeled disease burden from pesticide residues (DALY rate 5.9, against 3.9 for fish), a modeled figure for Iran only. We found no study on pregnancy, kidney disease or drug interactions for either food.

Sources

1. cpkl-daily-r8-01 · food composition data
   Cucumber, with peel, raw (Foundation Foods, release 2026-04-30): Potassium, K 169.6 mg per 100 g, range 136.0-211.0, median 169.8, 8 samples; Vitamin K (phylloquinone) 24.0 ug, range 16.0-32.2, median 24.8, 8 samples
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Cucumber, with peel, raw · checked 2026-10-01
2. cpkl-daily-r8-02 · food composition data
   Cucumber, raw, flesh and skin (CoFID 13-523): Energy 14 kcal; Water 96.5 g; AOAC fibre 0.7 g; Total sugars 1.2 g; Protein 1.0 g; Fat 0.6 g per 100 g
   CoFID 2021 (Public Health England), code 13-523, OGL v3.0 · checked 2026-10-01
3. cpkl-daily-r8-03 · portion data
   Cucumber, raw, FNDDS code 75111000, fdc_id 2709784: 1 piece/slice 10 g; 1 stick 10 g; 1 regular 200 g; 1 miniature 65 g; 1 cup 120 g; Quantity not specified 60 g
   USDA FNDDS 2021-2023, food code 75111000, FDC 2709784 · checked 2026-10-01
4. cpkl-daily-r8-11 · controlled experiment
   Children ate 54 % more cucumber when served a large compared with a smaller portion (difference of 49 g; P<0·001).
   Public Health Nutr, 2015 · checked 2026-10-01
5. cpkl-daily-r8-06 · food chemistry study
   Among all treatments, boiling was the most effective method for reducing antinutritional compounds. Phytate concentration decreased from 81.05 to 16.62 mg/g, corresponding to an apparent retention of only 20.5% relative to raw leaves. Similarly, oxalate concentration declined by approximately 82%, while tannins were reduced by nearly 50%.
   Molecules, 2026 · checked 2026-10-01
6. cpkl-daily-r8-07 · cluster randomized trial
   The villages were randomly assigned to receive 25 g of guava (guava group (GG)), banana (banana group (BG)), or cucumber (cucumber group (CG)) along with a SNP meal for 140 days. ... Higher hemoglobin (P = 0.002), serum ferritin (SF; P < 0.001), vitamin C (P = 0.047), and lower soluble transferrin receptor (sTfR; P < 0.001) causing decreased prevalence of iron deficiency (ID) (P = 0.003) were observed in the GG compared with BG and CG.
   Ann N Y Acad Sci, 2021 · checked 2026-10-01
7. cpkl-daily-r8-05 · retention factors
   USDA-RETN-R6:3005 VEG,GREENS,BOILED,WATER COVER DRAIN, group Vegetables and Vegetable Products: vitamin_c_mg 55% retained, folate_total_ug 60%, thiamin_mg 80%, potassium_mg 85%, calcium_mg 95%, iron_mg 95%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Code 3005 · checked 2026-10-01
8. cpkl-daily-r8-09 · randomized pilot trial
   Plasma glutathione peroxidase activity, contents of vitamin C, total phenolics were significantly increased, while plasma uric acid content significantly decreased in both groups at the end of the intervention.
   J Nutr Health Aging, 2015 · checked 2026-10-01
9. cpkl-daily-r8-12 · cross-sectional study
   Among iron-rich foods, tamarind (aOR = 0.75; 95% CI: 0.610, 0.929) and pumpkin leaves (aOR = 0.77; 95% CI: 0.605, 0.974) were associated with lower odds of anaemia.
   Matern Child Nutr, 2025 · checked 2026-10-01
10. cpkl-daily-r8-13 · outbreak case-control study
    Multifactorial analysis showed that the infection was significantly associated with the consumption of cucumber in sauce (aOR = 4.44, 95%CI = 1.23-16.06).
    Int J Food Microbiol, 2025 · checked 2026-10-01
11. cpkl-daily-r8-14 · case report
    Acute food poisoning due to cucurbitacin - containing pumpkin is rare but can occur in small gardening units in association with higher outside temperatures. ... Bitter taste is essential to diagnose cucurbitacin intoxications.
    Dtsch Med Wochenschr, 2020 · checked 2026-10-01
12. cpkl-daily-r8-15 · risk assessment
    The three food items with the highest DALY rates from pesticide residues were cucumber (5.9), fish (3.9), and date (2.1).
    Food Chem Toxicol, 2025 · checked 2026-10-01
13. cpkl-daily-r8-08 · randomized controlled trial
    Study 2 was a parallel trial (n = 38) lasting 12 weeks, with freeze-dried whole fruits (3.6 g/day) or a cucumber-based matched control supplement. ... On average, bitter gourd intervention reduced FPG by ∼0.05 mmol/L per week, whereas FPG remained unchanged following placebo.
    J Ethnopharmacol, 2025 · checked 2026-10-01
14. cpkl-daily-r8-10 · cluster randomized trial
    Both the feasibility and acceptability of the intervention to nursery staff and the willingness of children to consume the vegetables met the green stop-go criteria, with children eating some part of the vegetables in 62.4% (745/1194) of instances where vegetables were offered.
    Int J Behav Nutr Phys Act, 2023 · checked 2026-10-01
15. cpkl-daily-r8-04 · portion data
    Sweet potato, squash, pumpkin, chrysanthemum, or bean leaves, cooked, FNDDS code 72133201, fdc_id 2709642: 1 cup 69 g; Quantity not specified 35 g; Vitamin A, RAE 154 ug per 100 g, 106.3 ug per cup; Calcium, Ca 32 mg per 100 g, 22.1 mg per cup
    USDA FNDDS 2021-2023, food code 72133201, FDC 2709642 · checked 2026-10-01