Celery and cucumber: the blood pressure data come from seed extracts

A meta-analysis of 10 randomized trials in 511 adults found that celery preparations lowered systolic blood pressure, with a standardized mean difference of -1.0 (95% CI -1.85 to -0.14). Most of those trials used celery seed or extract, not stalks or juice, and the results varied widely between small trials. A standardized difference is not a number of mmHg. The stalk you buy is mostly water. Celery and cucumber are both about 95% water, and raw celery carries about 97 mg of sodium per 3.5 oz (100 g) against 1.5 mg in cucumber. Celery also has more potassium, 265 mg per 3.5 oz (100 g) against 170 mg, with celery samples ranging from 170 to 395 mg. A US stalk of celery weighs 1.4 oz (40 g) and a regular cucumber 200 g.

How much is actually in it

• Raw celery carries about 97 mg sodium per 3.5 oz (100 g) against about 1.5 mg in raw cucumber, so celery is the saltier of the two by a wide margin. — USDA Foundation samples, 8 per food (n = 16) Evidence E source
  Celery 97.21 mg/100 g (63-124), cucumber 1.515 mg/100 g (0-5.28)
• Raw celery averages 265 mg potassium per 3.5 oz (100 g) and raw cucumber 170 mg, with celery samples ranging more than twofold. — USDA Foundation samples, 8 per food (n = 16) Evidence E source
  Celery 265.2 mg/100 g (170-395), cucumber 169.6 mg/100 g (136-211)
• Both are about 95% water: 95.2 g per 3.5 oz (100 g) in celery and 95.9 g in cucumber, with almost no spread between samples. — USDA Foundation samples, 8 per food (n = 16) Evidence E source
  Celery 95.2 g (93.48-96.06), cucumber 95.87 g (95.38-96.38)
• The UK composition table gives a second figure: 77 mg sodium and 304 mg potassium per 3.5 oz (100 g) raw celery, against 4 mg and 156 mg in raw cucumber. — UK composition table entries 13-636 and 13-523 Evidence E source
  Celery Na 77 mg, K 304 mg, cucumber Na 4 mg, K 156 mg per 3.5 oz (100 g)
• In 16 celery-allergic patients the celeriac cultivar Anita gave smaller skin reactions than Prinz (5.0 vs 7.0 mm), in line with its lower Api g 1 allergen content. — 16 celery-allergic patients confirmed by blinded challenge (n = 16) Evidence C source
  Skin prick wheal 5.0 mm (Anita) vs 7.0 mm (Prinz), P = .047

What a real portion looks like

• A US survey stalk of celery weighs 1.4 oz (40 g) and a regular cucumber 200 g, while a cup of either is 120 g. — US survey portion weights Evidence E source
  Celery stalk 40 g, cup 120 g, cucumber regular 200 g, cup 120 g
• The cucumber arm of a 30-day randomized pilot in adults over 60 took 12.5 g of juice powder a day, equal to 11 oz (300 g) of fresh cucumber. — 16 men and 9 women over 60, Tianjin, China, 30 days (n = 25) Evidence B source
  Dose 300 g fresh cucumber equivalent a day

What your body absorbs

• No human study measures how well nutrients from celery or cucumber are absorbed, so nothing can be said about bioavailability from either. — PubMed corpus snapshot Evidence E source
  —

What cooking and storage change

• Boiling celery in unsalted water drops sodium from 77 to 43 mg and potassium from 304 to 170 mg per 3.5 oz (100 g) in the UK table. — UK composition table entries 13-636 and 13-637 Evidence E source
  Na 77 to 43 mg, K 304 to 170 mg per 3.5 oz (100 g) after boiling
• For vegetables boiled in water to cover and drained, USDA retention factors keep 75% of vitamin C, 65% of folate and 90% of potassium. — USDA vegetable group, boiled and drained Evidence E source
  Vitamin C 75%, folate 65%, potassium 90%, sodium 95% retained
• Cooking does not make celery safe for allergic people: 6 of 11 patients still reacted to cooked celery and 5 of 5 to celery spice in blinded challenges. — 12 patients with celery allergy, Germany (n = 12) Evidence C source
  6/11 positive to cooked celery (110 C, 15 min), 5/5 to celery spice

What it does to your health

• In a triple-blind crossover trial of 50 hypertensive patients, 1.34 g a day of celery seed extract for 4 weeks lowered anxiety scores by 6.78 points. — 50 hypertensive patients on usual medication, Iran, 4 weeks per arm (n = 50) Evidence B source
  BAI -6.78 (P < 0.001), BDI -3.63 (P < 0.01)
• After 30 days of cucumber powder, older adults had higher plasma vitamin C and glutathione peroxidase activity, but overall antioxidant capacity (FRAP) did not change. — healthy adults over 60, 30-day supplementation (n = 25) Evidence B source
  Vitamin C, total phenolics, GPx up, uric acid down, FRAP unchanged (no sizes in abstract)

Safety, limits and interactions

• In Thai markets, 53.3% of celery samples carried intestinal parasites, among the highest of ten vegetables tested. — 300 vegetable samples from 10 markets, Khon Kaen, Thailand (n = 300) Evidence C source
  Celery 53.3% contaminated, overall 36.0%
• A hepatitis E outbreak in China was traced to cucumber in sauce (aOR 4.44) contaminated through pans shared with raw pork. — 80 people exposed at a funeral dinner, Yantai, China, 2022 (n = 80) Evidence C source
  AOR 4.44 (95% CI 1.23-16.06) for eating cucumber in sauce

What people believe that the data does not support

• A meta-analysis of 10 randomized trials with 511 adults found celery preparations lowered systolic blood pressure (SMD -1.0) and diastolic blood pressure (SMD -0.93). — 511 adults in 10 RCT arms, mostly celery seed or extract preparations (n = 511) Evidence A source
  SBP SMD -1.0 (95% CI -1.85 to -0.14), DBP SMD -0.93 (-1.54 to -0.33)
• The EU register lists claims that celery helps the kidneys eliminate water or drains the body as non-authorized. — EU food labeling Evidence E source
  —

Who this works differently for

• Raw cucumber with peel holds about 24 micrograms of vitamin K1 per 3.5 oz (100 g), relevant for people on warfarin who keep vitamin K intake steady. — USDA Foundation samples, 8 (n = 8) Evidence E source
  24.0 ug/100 g phylloquinone (16.0-32.2)
• In an Iranian pesticide residue assessment, cucumber had the highest disease burden rate of any food at 5.9 DALYs per 100,000. — Iranian food supply, pooled residue data Evidence C source
  Cucumber DALY rate 5.9, fish 3.9, date 2.1

The bottom line

The other trials here also used concentrates. In a triple-blind crossover trial in 50 Iranian patients with high blood pressure, 1.34 g a day of celery seed extract capsules for 4 weeks lowered anxiety scores by 6.78 points. For cucumber, 25 adults over 60 in China took 12.5 g of cucumber juice powder a day for 30 days, equal to 11 oz (300 g) of fresh cucumber. Plasma vitamin C and glutathione peroxidase rose, and overall antioxidant capacity did not change. That pilot had no placebo arm, and the same rises appeared in the lotus root group. The EU lists claims that celery helps the kidneys eliminate water or drains the body as non-authorized. We found no human study on how well nutrients from either vegetable are absorbed. Boiling celery in unsalted water drops sodium from 77 to 43 mg and potassium from 304 to 170 mg per 3.5 oz (100 g) in the UK table, where the raw and boiled figures may come from different samples. Celery allergy survives cooking. In German double-blind challenges, 6 of 11 allergic patients still reacted to cooked celery and 5 of 5 to celery spice. Among 16 celery-allergic patients, the celeriac cultivar Anita gave smaller skin reactions than Prinz, 5.0 against 7.0 mm. In markets in one Thai province, 53.3% of celery samples carried intestinal parasites. A hepatitis E outbreak at a funeral dinner in China was traced to cucumber in sauce (adjusted odds ratio 4.44, 95% CI 1.23 to 16.06), contaminated through pans shared with raw pork. If you take warfarin and keep vitamin K steady, raw cucumber with peel holds about 24 micrograms of vitamin K1 per 3.5 oz (100 g). An Iranian model of pesticide residues ranked cucumber highest of any food, at 5.9 disability-adjusted life years per 100,000, for Iran only.

Sources

1. clcu-r3-01 · dataset
   Celery, raw | Sodium, Na 97.21 MG | range 63.0-124.0 (median 99.5), 8 samples; Cucumber, with peel, raw | Sodium, Na 1.515 MG | range 0.0-5.28 (median 0.0), 8 samples
   USDA FoodData Central Foundation Foods, release 2026-04-30 (Celery, raw; Cucumber, with peel, raw) · checked 2026-09-29
2. clcu-r3-02 · dataset
   Celery, raw | Potassium, K 265.2 MG | range 170.0-395.0 (median 248.5), 8 samples; Cucumber, with peel, raw | Potassium, K 169.6 MG | range 136.0-211.0 (median 169.8), 8 samples
   USDA FoodData Central Foundation Foods, release 2026-04-30 · checked 2026-09-29
3. clcu-r3-03 · dataset
   Celery, raw | Water 95.2 G | range 93.48-96.06 (median 95.6), 8 samples; Cucumber, with peel, raw | Water 95.87 G | range 95.38-96.38 (median 95.94), 8 samples
   USDA FoodData Central Foundation Foods, release 2026-04-30 · checked 2026-09-29
4. clcu-r3-05 · dataset
   13-636 Celery, raw | Potassium (mg) 304 | Sodium (mg) 77; 13-523 Cucumber, raw, flesh and skin | Potassium (mg) 156 | Sodium (mg) 4
   CoFID 2021, Public Health England, OGL v3.0, codes 13-636 (Celery, raw) and 13-523 (Cucumber, raw, flesh and skin) · checked 2026-09-29
5. clcu-r3-14 · diagnostic comparison study
   From the 10 investigated celeriac cultivars, two cultivars elicited significantly different skin reactivity ("Anita": 5.0 [2.0-12.0] mm vs "Prinz": 7.0 [3.0-9.5] mm; P = .047).
   Clin Exp Allergy, 2018 · checked 2026-09-29
6. clcu-r3-08 · dataset
   Celery, raw [75109000] | 1 stalk 40 g | 1 cup 120 g; Cucumber, raw [75111000] | 1 regular 200 g | 1 cup 120 g
   USDA FNDDS 2021-2023, food codes 75109000 (Celery, raw) and 75111000 (Cucumber, raw) · checked 2026-09-29
7. clcu-r3-11 · RCT (pilot)
   During the intervention period, the subjects received daily 25g of lotus root powder or 12.5g of cucumber powder, which was equivalent to 300g of fresh lotus root or cucumber, respectively.
   J Nutr Health Aging, 2015 · checked 2026-09-29
8. clcu-r3-19 · corpus absence
   corpus_search (celery OR cucumber) AND (absorption OR bioavailability OR bioaccessib* OR digestib* OR uptake): 3 records, all on allergy (12269935, 23509907, 24067338), none on nutrient absorption
   PubMed corpus snapshot pubmed:469185, 2026-09 · checked 2026-09-29
9. clcu-r3-06 · dataset
   13-636 Celery, raw | Potassium (mg) 304 | Sodium (mg) 77; 13-637 Celery, boiled in unsalted water | Potassium (mg) 170 | Sodium (mg) 43
   CoFID 2021, Public Health England, OGL v3.0, codes 13-636 and 13-637 (Celery, boiled in unsalted water) · checked 2026-09-29
10. clcu-r3-07 · dataset
    USDA-RETN-R6:3775 VEG,OTHER,BLD,WATER COVER,DRAINED | folate_total_ug 65% | vitamin_c_mg 75% | potassium_mg 90% | sodium_mg 95%
    USDA Table of Nutrient Retention Factors, Release 6 (2007), Retn_Code 3775 VEG,OTHER,BLD,WATER COVER,DRAINED · checked 2026-09-29
11. clcu-r3-13 · provocation study
    Six out of 11 patients showed a positive DBPCFC to cooked celery and five out of five patients to celery spice.
    Allergy, 2002 · checked 2026-09-29
12. clcu-r3-10 · RCT (crossover)
    Fifty hypertensive patients received 4 placebo or celery seed extract capsules (1.34 g per day) for 4 weeks as a supplement to their usual medication regimen.
    Inflammopharmacology, 2023 · checked 2026-09-29
13. clcu-r3-12 · RCT (pilot)
    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 2026-09-29
14. clcu-r3-15 · prevalence survey
    Peppermint showed the highest prevalence rate at 70.0%, followed by celery and Thai basil at 53.3% each.
    Am J Trop Med Hyg, 2025 · checked 2026-09-29
15. clcu-r3-16 · case-control
    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 2026-09-29
16. clcu-r3-09 · meta-analysis
    The results demonstrated significant therapeutic effects of celery on systolic blood pressure (SMD: -1.0; 95% CI: -1.85 to -0.14), diastolic blood pressure (SMD: -0.93; 95% CI: -1.54 to -0.33)
    Front Nutr, 2025 · checked 2026-09-29
17. clcu-r3-18 · regulation
    POL-HC-6622 Apium graveolens - common name : celery Used to enhance the renal elimination of water / "Used to facilitate the elimination functions of the organism" / "Used for the drainage of the organism" / "Stimulates the elimination function of the organism" / "Contributes to the functionary of the urinary tract" Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6622, snapshot 2026-09-21 · checked 2026-09-29
18. clcu-r3-04 · dataset
    Cucumber, with peel, raw | 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 2026-09-29
19. clcu-r3-17 · 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 2026-09-29