Asparagus and celery: folate in one, a pressure result that belongs to seeds

A meta-analysis of 10 randomized trial arms in 511 adults found that celery preparations lowered systolic blood pressure by a standardized mean difference of 1.0 (95% CI 0.14 to 1.85), a scale that cannot be read as mmHg. Most of those arms used seed extracts or concentrated preparations. In a subgroup analysis, arms that used seeds or more than 1,000 mg a day of a preparation showed larger effects than other parts of the plant. That describes the trials, not an amount to take, and we have no card on a safe upper dose of celery seed extract. The result does not carry over to celery stalks or juice. The difference that holds on a plate is folate. Raw green asparagus averages 182.5 micrograms per 3.5 oz (100 g) across 8 USDA samples, and a 135 g cup gives about 246, recalculated from 100 g. Celery is harder to pin down. Across 8 samples its potassium ran from 170 to 395 mg per 3.5 oz (100 g) and its calcium from 29 to 84 mg, so any single label value is a rough guide.

How much is actually in it

• Green asparagus is the folate vegetable of the pair: USDA samples average 182.5 ug per 3.5 oz (100 g), with 8 samples ranging from 143 to 207 ug. — USDA Foundation Foods, Asparagus, green, raw, 8 analyzed samples (n = 8) Evidence E source
  Folate 182.5 ug per 3.5 oz (100 g) (range 143.0 to 206.6); vitamin C 9.2 mg (5.4 to 12.4); potassium 277.5 mg (254 to 301); fiber 1.9 g (1.6 to 2.2)
• Celery varies far more from sample to sample: potassium runs from 170 to 395 mg and calcium from 29 to 84 mg per 3.5 oz (100 g) across 8 USDA samples. — USDA Foundation Foods, Celery, raw, 8 analyzed samples (n = 8) Evidence E source
  Potassium 265.2 mg per 3.5 oz (100 g) (range 170 to 395); sodium 97.2 mg (63 to 124); calcium 46.3 mg (28.6 to 83.6); CoFID raw celery potassium 304 mg, sodium 77 mg

What a real portion looks like

• A cup of raw asparagus weighs 4.8 oz (135 g) and a cup of raw celery 120 g, while one asparagus spear is 16 g and one celery stalk 40 g. — FNDDS foods Asparagus, raw (75100800) and Celery, raw (75109000), US household measures Evidence E source
  Asparagus: 1 spear 16 g, 1 cup 135 g, quantity not specified 68 g; celery: 1 stick 4 g, 1 stalk 40 g, 1 cup 120 g, quantity not specified 60 g; a cup of asparagus gives about 246 ug folate (recalculated)

What cooking and storage change

• Steaming keeps more of the folate that asparagus is eaten for: the USDA table keeps 85% after steaming against 65% after boiling in water that is poured away. — USDA retention factors for the group Vegetables and Vegetable Products, the group both asparagus and celery belong to Evidence E source
  Steamed: folate 85%, vitamin C 85%, potassium 100%; boiled in covering water and drained: folate 65%, vitamin C 75%, potassium 90%
• Cooking does not make celery safe for everyone who is allergic to it: 6 of 11 patients still reacted to cooked celery and all 5 tested reacted to celery spice. — 12 patients with a history of reactions to raw or cooked celery, double-blind placebo-controlled food challenges (n = 12) Evidence C source
  Positive challenge to cooked celery (110 C for 15 min) in 6 of 11; to celery spice in 5 of 5
• Asparagus allergy can come from handling it raw: two patients reacted while preparing fresh asparagus, and their skin tests were positive with raw asparagus but negative with cooked. — 2 atopic patients with conjunctivitis, rhinitis and cough while preparing fresh asparagus (n = 2) Evidence C source
  Skin prick positive with raw green and white asparagus, negative with cooked; IgE binding not inhibited after heating extract to 100 C

What it does to your health

• A meta-analysis of 10 randomized trials in 511 adults found celery preparations lowered systolic blood pressure by a standardized mean difference of 1.0. — adults in 10 randomized controlled trial arms (9 studies), 511 participants, celery preparations versus non-celery control (n = 511) Evidence A source
  Systolic BP SMD -1.0 (95% CI -1.85 to -0.14); diastolic BP SMD -0.93 (95% CI -1.54 to -0.33); fasting glucose SMD -0.80; triglycerides SMD -1.18
• In a 4-week crossover RCT in 50 hypertensive patients, 1.34 g a day of celery seed extract cut Beck anxiety scores by 6.78 points. — 50 hypertensive patients on usual medication, celery seed extract capsules 1.34 g/day versus placebo, 4 weeks each with 4-week washout (n = 50) Evidence B source
  Mean reduction in BAI 6.78 (P < 0.001) and BDI 3.63 (P < 0.01) during celery treatment
• In 177,148 UK Biobank adults, a strong liking for asparagus went with 31% lower all-cause mortality over 3.4 years. — 177,148 UK Biobank participants who completed a food preference questionnaire, mean follow-up 3.4 years, 3355 deaths (n = 177148) Evidence C source
  High versus low preference for asparagus HR 0.69 (95% CI 0.62 to 0.77)

Safety, limits and interactions

• Raw celery can carry intestinal parasites: in markets in northeast Thailand, 53.3% of celery samples were contaminated. — 300 vegetable samples of 10 kinds from 10 markets in Khon Kaen province, Thailand (n = 300) Evidence C source
  Overall parasite prevalence 36.0%; celery and Thai basil 53.3% each; peppermint 70.0%
• Asparagus or celery seed extracts sold as dietary supplements in the US fall under DSHEA (1994), so the FDA does not approve them for safety or effectiveness before they are sold. — Dietary supplements sold in the United States Evidence E source
  No FDA premarket approval of safety, effectiveness or labeling

What people believe that the data does not support

• Asparagus marketed for fat loss rests on an extract: 30 mg a day of asparagus-derived 20-hydroxyecdysone for 12 weeks in 20 trained men reduced regional fat. — 20 healthy young men doing supervised resistance training 3 times a week, 30 mg/day 20-hydroxyecdysone from Asparagus officinalis extract or placebo, 12 weeks (n = 20) Evidence B source
  Arm, leg and abdominal fat reduced in the 20E group; arm fat reduction greater than placebo (p < 0.05)
• The EU refused the claim that asparagus supports kidney excretion or urine flow. — EU Register on nutrition and health claims, claim POL-HC-6652 Evidence E source
  Status Non-authorized

Who this works differently for

• For people allergic to celery, the variety matters: in 14 patients one celeriac cultivar caused fewer symptoms on oral challenge than another. — 16 celery-allergic patients confirmed by double-blind placebo-controlled challenge, 14 challenged orally with two celeriac cultivars (n = 16) Evidence B source
  Cultivar Anita induced fewer symptoms than Prinz (P < .001); skin prick 5.0 versus 7.0 mm (P = .047); Prinz had more Api g 1
• Across studies of pollen-related food allergy, heating removed symptoms completely in 46% of people allergic to celery. — adults with pollen-related food allergy, four in vivo heat-processing studies with 116 participants in total (n = 116) Evidence C source
  Symptoms eradicated by heating in 46% of celery-allergic and 15-71% of hazelnut-allergic individuals

What is still unknown

• The same meta-analysis found the effect came mainly from celery seeds or preparations above 1,000 mg a day, not from other parts of the plant. — subgroup analysis of 10 randomized trial arms of celery preparations in adults (n = 511) Evidence A source
  Larger effects for seeds and for doses over 1,000 mg/day than for other celery parts

The bottom line

Steaming keeps 85% of folate by USDA group factors, against 65% after boiling in water that is drained away. Those factors date from 1975 and name neither vegetable. We found no study on how either is absorbed and none that compares the two directly. Celery seed extract at 1.34 g a day for 4 weeks cut anxiety scores by 6.78 points on the Beck scale, in a placebo-controlled crossover trial in 50 people with high blood pressure on their usual medication. That was a capsule standardized for one compound, tested briefly at one center. Asparagus marketed for fat loss also rests on an extract. In 20 young men doing supervised weight training, 30 mg a day of 20-hydroxyecdysone taken from asparagus for 12 weeks reduced arm, leg and abdominal fat, and the arm loss was the one reported as greater than placebo. That is an isolated compound at a dose no serving provides, with 10 men per group, and we have no card on its safety. The EU refused a claim that asparagus supports kidney excretion or urine flow. In 177,148 UK Biobank adults, a strong liking for asparagus went with 31% lower mortality over 3.4 years (HR 0.69, 95% CI 0.62 to 0.77). That measured preference, not intake, and liking asparagus marks a whole way of eating. The real caution here is celery allergy. In a double-blind challenge study, 6 of 11 allergy clinic patients still reacted to celery cooked at 110 C for 15 minutes, and all 5 tested reacted to celery spice. Across studies of pollen-related food allergy, heating removed symptoms completely in 46% of people allergic to celery, evidence the authors rate as low. Which allergen a person reacts to decides whether heat helps. In 14 patients one celeriac cultivar caused fewer symptoms than another, but that was celeriac root, and cultivar names are not on supermarket labels. Asparagus allergy can start at the chopping board: two patients reacted while preparing it raw, with skin tests positive to raw asparagus and negative to cooked. Raw celery can carry parasites. In markets in northeast Thailand 53.3% of celery samples were contaminated, and the authors point to washing. We have no card on who is most at risk from these parasites. We have no card on either vegetable for pregnancy or medicines, and none on the safety of celery seed extract or on taking it alongside blood pressure drugs. The anxiety trial enrolled people with high blood pressure on their usual medication, which is why this gap matters. In the US, supplements do not go through FDA approval the way medicines do, so anyone who takes medication, is pregnant or has a chronic illness should talk to a doctor before taking celery seed extract.

Sources

1. aspcel-r2-01 · USDA FoodData Central Foundation Foods, dataset
   Asparagus, green, raw (Foundation, FDC 2710823): Folate, total 182.5 UG range 143.0-206.6, samples 8; Vitamin C 9.153 MG range 5.38-12.4, samples 8; Potassium, K 277.5 MG range 254.0-301.0, samples 8; Fiber, total dietary 1.883 G range 1.59-2.21, samples 8; CoFID 13-157 Asparagus, raw folate 175 ug
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Asparagus, green, raw (FDC 2710823) · checked 2026-09-29
2. aspcel-r2-02 · USDA FoodData Central Foundation Foods, dataset
   Celery, raw (Foundation, FDC 2346405): Potassium, K 265.2 MG range 170.0-395.0, samples 8; Sodium 97.21 MG range 63-124, samples 8; Calcium, Ca 46.28 MG range 28.6-83.6, samples 8; CoFID 13-636 Celery, raw potassium 304 mg, sodium 77 mg, calcium 41 mg
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Celery, raw (FDC 2346405) · checked 2026-09-29
3. aspcel-r2-03 · USDA FNDDS portion weights, dataset
   Asparagus, raw (FNDDS 75100800, FDC 2709767): 1 piece 4 g; 1 spear 16 g; 1 cup 135 g; Quantity not specified 68 g. Celery, raw (FNDDS 75109000, FDC 2709778): 1 piece 4 g; 1 stick 4 g; 1 stalk 40 g; 1 cup 120 g; Quantity not specified 60 g
   USDA FNDDS 2021-2023, food codes 75100800 (FDC 2709767) and 75109000 (FDC 2709778) · checked 2026-09-29
4. aspcel-r2-04 · USDA Table of Nutrient Retention Factors, dataset
   USDA-RETN-R6:3784 VEG,OTHER,STEAMED, group Vegetables and Vegetable Products: folate_total_ug 85% retained, vitamin_c_mg 85%, thiamin_mg 90%, potassium_mg 100%; USDA-RETN-R6:3775 VEG,OTHER,BLD,WATER COVER,DRAINED: folate_total_ug 65%, vitamin_c_mg 75%, thiamin_mg 80%, potassium_mg 90%
   USDA Table of Nutrient Retention Factors, Release 6, 2007, Retn_Codes 3784 and 3775 · checked 2026-09-29
5. aspcel-r2-10 · food challenge study in humans
   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
6. aspcel-r2-12 · case series
   Skin-prick tests with native green and white asparagus were strongly positive, but negative with cooked asparagus.
   Clin Exp Allergy, 1996 · checked 2026-09-29
7. aspcel-r2-05 · systematic review and meta-analysis of randomized controlled trials
   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), fasting plasma glucose (SMD: -0.80; 95% CI: -1.58 to -0.01), and triglyceride (SMD: -1.18; 95% CI: -1.45 to -0.91).
   Front Nutr, 2025 · checked 2026-09-29
8. aspcel-r2-07 · randomized controlled trial in humans
   In the celery treatment step, the mean reduction in BAI and BDI scores were 6.78 (P < 0.001) and 3.63 (P < 0.01), respectively.
   Inflammopharmacology, 2023 · checked 2026-09-29
9. aspcel-r2-14 · prospective cohort study
   Higher preference for asparagus (hazard ratio (95% confidence interval)): 0.69 (0.62, 0.77)), aubergine (0.79 (0.72, 0.87)), black pepper (0.72 (0.64, 0.81)), broccoli (0.69 (0.61, 0.79)), butternut squash (0.75 (0.68, 0.83)), and extra virgin olive oil (0.67 (0.58, 0.78)) was linked to lower all-cause mortality, whereas higher preference for regular fizzy drinks (1.38 (1.24, 1.54)) was linked to higher mortality across all analyses.
   Sci Rep, 2026 · checked 2026-09-29
10. aspcel-r2-13 · 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
11. sf-dshea-3 · agency advice
    The Federal Food, Drug, and Cosmetic Act was amended in 1994 by the Dietary Supplement Health and Education Act, often referred to as DSHEA, which defined “dietary supplement” and set out the FDA’s authority regarding such products....The FDA does NOT have the authority to approve dietary supplements for safety and effectiveness, or to approve their labeling, before the supplements are sold to the public.
    FDA, FDA 101: Dietary Supplements · checked 2026-10-08
12. aspcel-r2-08 · randomized controlled trial in humans
    The 20E group showed significant reductions in arm (p<0.01), leg (p<0.05), and abdominal fat (p<0.05), with arm fat reduction significantly greater than in the PLA group (p<0.05).
    J Nutr Sci Vitaminol (Tokyo), 2025 · checked 2026-09-29
13. aspcel-r2-15 · EU health claim decision
    POL-HC-6652 Asparagus officinalis Supports the excretory function of the kidneys /contributes to urinary flow Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6652, snapshot 2026-09-21 · checked 2026-09-29
14. aspcel-r2-09 · randomized controlled challenge study in humans
    Moreover, "Anita" induced fewer symptoms after a controlled oral-celeriac challenge in 14 patient (P < .001).
    Clin Exp Allergy, 2018 · checked 2026-09-29
15. aspcel-r2-11 · systematic review
    Heating was found to completely eradicate symptoms in 15⁻71% of hazelnut allergic and 46% of celery allergic individuals.
    Nutrients, 2018 · checked 2026-09-29
16. aspcel-r2-06 · systematic review and meta-analysis of randomized controlled trials
    Subgroup analysis revealed that celery seeds or celery preparations exceeding 1,000 mg/day were more effective than other parts of celery.
    Front Nutr, 2025 · checked 2026-09-29