Eggplant: the blood pressure trial used a capsule

Eggplant has one randomised trial behind a health effect, and that trial did not give anyone eggplant to eat. A hundred stressed Japanese adults with high-normal or mildly raised blood pressure took capsules holding 1.2 g of eggplant powder a day for 12 weeks. Their clinic blood pressure ended lower than on placebo. The abstract reports p-values and never says by how many mmHg, and we have not yet taken the size from the full paper. The powder came from the juice of about 22 g of fresh eggplant, heated, pressed and freeze-dried, which is roughly a quarter of a cup. We found no trial of eggplant cooked as a normal dish. The other popular claim, that eggplant water lowers cholesterol, was tested in Brazil on 38 adults for 5 weeks and did no better than placebo. Everything else we have is observational. In three large US cohorts, eggplant counted together with summer squash landed in the top 5 of 52 fruits and vegetables for healthy blood markers. In the UK Biobank, people who said they like aubergine had a 21 percent lower death rate over 3.4 years, and that study asked about liking and never measured how much anyone ate. Studies of this kind show who eats a food. They cannot show that the food did the work.

The numbers, per 100 g

How much is actually in it

• Across 8 USDA Foundation samples of raw eggplant, folate ranged from 10 to 28 µg per 100 g and copper from 0.035 to 0.086 mg, while fibre stayed between 2.18 and 2.83 g. — 8 analysed samples of raw eggplant, USDA Foundation Foods (n = 8) Evidence E source
  Folate spread 90%, copper 84%, fibre 27% between samples

What a real portion looks like

• The daily dose that lowered blood pressure in the 2019 Japanese trial was 1,200 mg of powder made from the juice of about 22 g of fresh eggplant, roughly a quarter of an 80 g cup. — same trial as eggp-b4-01, 100 Japanese adults, 12 weeks (n = 100) Evidence B source
  Dose equivalent of about 22 g fresh eggplant a day, heated, pressed to remove the pulp and freeze-dried
• A cup of raw eggplant weighs about 80 g and a cup cooked without fat about 95 g, so a raw cup carries roughly 2 g of fibre at 2.45 g per 100 g. — US household measures, FNDDS Evidence E source
  1 cup raw 80 g, 1 cup cooked no added fat 95 g, 1 whole raw 500 g

What cooking and storage change

• A single case report describes a 27-year-old man who had anaphylaxis minutes after eating baked eggplant, with skin tests positive to both cooked and fresh eggplant, so cooking did not remove the allergen for him. — single case report, 27-year-old man with lipid transfer protein sensitisation (n = 1) Evidence D source
  Anaphylaxis with loss of consciousness; prick-by-prick tests positive to cooked and fresh eggplant
• By the USDA retention table for the vegetable group, baking keeps about 85% of folate while frying keeps 70%, and copper and potassium are rated at 100% for both methods. — USDA factors for the group Vegetables and Vegetable Products; eggplant is not named individually Evidence E source
  Folate retained 85% baked (3771) and 70% fried (3780); vitamin C 85% for both; copper and potassium 100%

What it does to your health

• In a 12-week randomised placebo-controlled trial in 100 stressed Japanese adults with high-normal blood pressure or grade 1 hypertension, capsules with 1.2 g of eggplant powder a day lowered clinic diastolic pressure at week 8 and both systolic and diastolic pressure at week 12 compared with placebo. — 100 Japanese adults with stress and high-normal blood pressure or grade 1 hypertension, not on blood pressure medication, 12 weeks (n = 100) Evidence B source
  Lower clinic diastolic pressure at week 8 (p = 0.024) and lower systolic pressure at week 12 (p = 0.046) versus placebo; the paper reports p-values, the abstract gives no mmHg difference
• In three US cohorts, eggplant grouped with summer squash ranked in the top 5 of 52 fruits and vegetables for favourable links with 14 cardiometabolic blood markers measured in 41,714 people. — Health Professionals Follow-up Study, Nurses' Health Study and NHSII; biomarkers in 41,714, disease follow-up in 207,241 over 32 years (n = 41714) Evidence C source
  Eggplant/summer squash among the top 5 high-metabolic-quality items; the disease hazard ratios refer to the whole high-quality group, not to eggplant alone

Safety, limits and interactions

• On 26 eggplant farms in Pangasinan, Philippines, up to 20% of eggplant fruit samples carried insecticide residues, mainly cypermethrin and chlorpyrifos. — 26 randomly selected eggplant farms in Sta. Maria, Pangasinan, Philippines (n = 26 farms) Evidence C source
  Up to 20% of fruit samples positive for insecticide residues at any sampling stage

What people believe that the data does not support

• In a 5-week placebo-controlled trial in 38 adults with high cholesterol, drinking eggplant infusion did not lower total or LDL cholesterol more than placebo, which does not support the Brazilian folk belief that it treats high cholesterol. — 38 hypercholesterolaemic adult volunteers in Brazil, 19 per group, 5 weeks, with and without dietary advice (n = 38) Evidence B source
  No difference versus placebo in total cholesterol, LDL, triglycerides or apolipoproteins; a within-group fall in the infusion arm was modest and transitory

Who this works differently for

• In a random sample of 741 people aged 5 to 60 in Mysore, India, 9.2% reported reactions after eating eggplant, while IgE-mediated eggplant allergy was estimated at about 0.8% and women were twice as likely as men to be sensitised. — 741 randomly selected rural and urban residents of Mysore, India, aged 5-60 (n = 741) Evidence C source
  Self-reported reactions 9.2%; IgE-mediated allergy about 0.8%; female to male sensitisation about 2 to 1
• In 80 postpartum women in Goiania, Brazil, eggplant intake correlated weakly with lead in colostrum (r = 0.27), and after adjustment the link held only for cooked squash, eggs and meats. — 80 puerperal women from one maternity hospital in Goiania, Brazil, 2008 (n = 80) Evidence C source
  R = 0.27, P = 0.015 for eggplant; not retained after logistic regression

What is still unknown

• Among 177,148 UK Biobank participants followed for 3.4 years, people with a high liking for aubergine had 21% lower all-cause mortality (HR 0.79), though the study measured liking and not how much aubergine was eaten. — 177,148 UK Biobank participants who completed a food preference questionnaire, 3,355 deaths (n = 177148) Evidence C source
  HR 0.79 (95% CI 0.72-0.87) for high versus low preference for aubergine
• In 72,680 Chinese women with 256 liver cancer cases, eggplant intake showed a nominal link with higher liver cancer risk that disappeared after correcting for testing 126 foods and nutrients. — 72,680 women in the Shanghai Women's Health Study, 1,267,391 person-years (n = 72680) Evidence C source
  Nominal positive association at P 0.05 only; no dietary variable associated after false discovery rate correction

The bottom line

Eat eggplant because you like it and it fits the meal. A cup of raw eggplant weighs about 80 g and carries roughly 2 g of fibre. Across eight USDA samples, fibre stayed between 2.18 and 2.83 g per 100 g, while folate swung from 10 to 28 µg and copper from 0.035 to 0.086 mg, so any single folate figure, ours included, is a rough guide. For vegetables as a group, the USDA reckons baking keeps about 85 percent of folate and frying about 70 percent, with copper and potassium rated at 100 percent. The table gives factors for vegetables as a group and does not list eggplant separately. If you are thinking of the blood pressure capsules, the trial only took people who were not on blood pressure medication, so it tells you nothing about adding them to those drugs. That is a conversation for your doctor. Allergy is the clearest reason to be careful. In a random sample of 741 people aged 5 to 60 in Mysore, India, 9.2 percent said eggplant gave them some reaction, while true allergy driven by IgE, the antibody behind classic food allergies, was estimated at about 0.8 percent. Women were about twice as likely as men to be sensitised. Cooking does not reliably help. One case report describes a 27-year-old man who went into anaphylaxis minutes after eating baked eggplant, and his skin tests reacted to cooked and fresh eggplant alike. If eggplant has ever made you react, see an allergist before trying it again in any form. On safety our cards are thin. One study of 26 farms in a single Philippine province found insecticide residues, mainly cypermethrin and chlorpyrifos, on up to 20 percent of fruit samples. That describes one region and says nothing about eggplant sold elsewhere. We hold no card on an upper limit for eggplant or on interactions with medicines, so this page cannot tell you anything about either. Two alarming signals faded on a closer look. In 72,680 Chinese women, a nominal link between eggplant and liver cancer disappeared once the authors corrected for testing 126 foods and nutrients at once. In 80 new mothers in Brazil, eggplant intake tracked weakly with lead in their first breast milk (r = 0.27), and that link did not survive adjustment. Neither result shows harm, and neither was designed to show safety.

Sources

1. eggp-b4-12 · reference dataset
   Eggplant, raw · Folate, total 20.0 UG, range 10.0-28.0 (median 22.0), samples 8 || Copper, Cu 0.06078 MG, range 0.0351-0.0863 (median 0.05715), samples 8 || Fiber, total dietary 2.448 G, range 2.18-2.83 (median 2.38), samples 8
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Eggplant, raw (FDC 2685577) · checked 2026-09-23
2. eggp-b4-02 · RCT
   In the clinical trial, the participants received daily ingestion of 1200 mg eggplant powder (300 mg powder containing 25% dextrin × 4), which was produced from approximately 22 g of the fresh eggplant.
   Nutrients, 2019 · checked 2026-09-23
3. eggp-b4-13 · reference dataset
   FNDDS 75111200 Eggplant, raw · 1 cup 80 g · 1 whole 500 g || FNDDS 75217010 Eggplant, cooked, no added fat · 1 cup 95 g · 1 slice 55 g
   USDA FNDDS, Eggplant raw, food code 75111200 · checked 2026-09-23
4. eggp-b4-05 · case report
   Eggplant allergy is rare and most of the previously described reactions were mild. ... Prick by prick skin tests were positive for eggplant, both cooked and fresh.
   Asian Pac J Allergy Immunol, 2018 · checked 2026-09-23
5. eggp-b4-11 · reference dataset
   USDA-RETN-R6:3771 VEG,OTHER,BAKED — folate_total_ug 85% · vitamin_c_mg 85% · copper_mg 100% · potassium_mg 100% || USDA-RETN-R6:3780 VEG,OTHER,FRIED — folate_total_ug 70% · vitamin_c_mg 85% · copper_mg 100% · potassium_mg 100%
   USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-23
6. eggp-b4-01 · RCT
   Participants in the eggplant group ingested capsules containing eggplant powder (1.2 g/day; 2.3 mg of ACh/day) for 12 weeks, whereas participants in the placebo group ingested placebo capsules. ... Eggplant powder intake significantly decreased the hospital diastolic blood pressure (DBP) at week 8 overall and in the normal-high BP group, and the systolic blood pressure (SBP) and DBP at week 12 overall and in the grade 1 hypertension group, compared to those of the placebo group.
   Nutrients, 2019 · checked 2026-09-23
7. eggp-b4-07 · prospective cohort
   Of 52 FV items, 19 were identified as high-metabolic quality (top 5: apples/pears, iceberg/head lettuce, raw spinach, alfalfa sprouts, and eggplant/summer squash).
   Am J Clin Nutr, 2024 · checked 2026-09-23
8. eggp-b4-06 · cross-sectional
   Cypermethrin and chlorpyrifos were the insecticide residues detected in eggplant fruit samples. A maximum of 20% of the eggplant samples tested positive for insecticide residues.
   Environ Health Prev Med, 2015 · checked 2026-09-23
9. eggp-b4-03 · RCT
   It has been believed that infusion of a powdered preparation of the fruit may reduce serum cholesterol. ... No differences were observed compared to control. ... The results suggest that S. melongena infusion had a modest and transitory effect, which was not different from that obtained with standard orientation for dyslipidemia patients (diet and physical activities).
   Braz J Med Biol Res, 2000 · checked 2026-09-23
10. eggp-b4-04 · cross-sectional
    Sixty-eight (9.2%) subjects reported adverse reactions to ingestion of eggplant ... females were twice as likely to be sensitized as males. ... The prevalence of IgE-mediated eggplant allergy is estimated at approximately 0.8%, with higher rates of sensitization in females.
    Clin Exp Allergy, 2008 · checked 2026-09-23
11. eggp-b4-10 · cross-sectional
    whereas the intake of squash (r = 0.26; P = 0.019) and eggplant (r = 0.27; P = 0.015) was positively correlated with the levels of lead. The correlation observed for cooked squash, eggs, pork and chicken meats, and chicken products was maintained after logistic regression adjustment.
    Rev Panam Salud Publica, 2011 · checked 2026-09-23
12. eggp-b4-08 · prospective cohort
    Higher preference for asparagus (hazard ratio (95% confidence interval)): 0.69 (0.62, 0.77)), aubergine (0.79 (0.72, 0.87))
    Sci Rep, 2026 · checked 2026-09-23
13. eggp-b4-09 · prospective cohort
    higher intakes of cooked wheaten foods, pear, grape and copper were inversely associated with liver cancer risk, while spinach, leafy vegetables, eggplant and carrots showed the positive associations. After considering multiple comparisons, no dietary variable was associated with liver cancer risk.
    J Nutr Sci, 2024 · checked 2026-09-23