Raw vegetables: what eating them uncooked changes, and what it does not

Raw and cooked vegetables each have trade-offs, and the strongest trial here is a narrow one. A randomized trial followed 153 adults starting chemotherapy for acute myeloid leukemia, in filtered rooms and on antimicrobial prophylaxis. Banning raw fruit and vegetables did not reduce major infections, at 29 percent on the cooked diet and 35 percent on the raw one, a gap that was not significant, in a trial not powered to find small differences. That result holds for that protected hospital setting only, and it does not tell anyone with a weakened immune system to drop the food rules their care team has set. In a cluster randomized trial of 81 Indonesian adults with poorly controlled type 2 diabetes, coaching to eat more raw vegetables cut HbA1c by 3.1 points over 12 weeks against 2.3 in controls, an adjusted difference of 0.55 points. That trial had only six clusters and no blinding, and people lost weight at the same time. A 120 g cup of mixed raw vegetables gives about 36 calories, 2.4 g of fiber and 34 mg of vitamin C in US survey data, and any single vegetable differs widely from that mix.

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• A cup (120 g) of mixed raw vegetables gives about 36 calories, 2.4 g fiber, 34 mg vitamin C, 316 mg potassium and 247 mcg vitamin A in US survey data. — US household measures, FNDDS (n = 1 food code) Evidence E source
  Per 100 g: energy 30 calories, fiber 2 g, vitamin C 28.7 mg, potassium 263 mg, vitamin A 206 mcg RAE; per cup 120 g: 36 calories, 2.4 g, 34.4 mg, 315.6 mg, 247.2 mcg

What your body absorbs

• In 8 women eating about 9.3 mg beta-carotene a day for 4 weeks, processed carrots and spinach raised plasma beta-carotene about three times more than the same vegetables raw. — 8 healthy women aged 23-36, raw vs thermally processed pureed carrots and spinach, two 4-week crossover periods (n = 8) Evidence C source
  Plasma beta-carotene rise about 3 times greater with processed than raw (P=0.09)
• In 16 young men, adding 3 scrambled eggs to a raw mixed-vegetable salad raised absorption of alpha-carotene, beta-carotene and lycopene 3 to 8 fold. — 16 healthy young men, raw mixed-vegetable salad with 3 g canola oil and 0, 75 or 150 g scrambled egg, single meals (n = 16) Evidence B source
  Total carotenoid AUC 125.7 vs 14.9 nmol/L x 10 h with 150 g egg vs none (P<0.0001), alpha-carotene, beta-carotene and lycopene 3-8 fold

What cooking and storage change

• Counting home cooking methods lowered estimated vitamin C intake from vegetables by 12.5% among 447 Spanish adults, and raw vegetables drove most between-person variation. — 447 adults (25.1% female, mean age 59.7) in the PREDIMAR trial, FFQ plus home cooking frequency questionnaire (n = 447) Evidence C source
  Vegetables -12.5%, legumes -88.0%, tubers -62.7% vitamin C when cooking counted; total 173.7 vs 160.1 mg/day

What it does to your health

• In a cluster randomized trial of 81 Indonesian adults with poorly controlled type 2 diabetes, coaching to eat more raw vegetables cut HbA1c by 3.1 points over 12 weeks against 2.3 in controls. — 81 adults aged 18-55 with type 2 diabetes and HbA1c 8% or more, six offices cluster randomized, 12 weeks (n = 81) Evidence B source
  HbA1c -3.1 vs -2.3 percentage points (P=0.009), adjusted effect -0.55 (95% CI -1.2 to -0.1)
• In 429,886 UK Biobank adults followed 12.6 years, higher intake of raw and of cooked vegetables was each linked with lower risk of developing type 2 diabetes and of death. — 429,886 UK Biobank participants free of diabetes, 12.6 years follow-up (n = 429886) Evidence C source
  Lower risk of transition to incident type 2 diabetes and to death (hazard ratios for vegetables not given in abstract)

Safety, limits and interactions

• Pooling prevalence studies from 1980 to 2019, parasites were found on about 6.7% and enteric viruses on about 7.9% of vegetable samples. — prevalence studies of vegetable samples worldwide, emphasis on lettuce Evidence C source
  Parasites 0.067 (95% CI 0.056-0.080), viruses 0.079 (95% CI 0.054-0.113), bacterial pathogens mostly under 0.023, S. aureus 0.096
• In Ethiopian farm and market samples, about half of raw vegetables and fruits carried bacteria or parasites, with lettuce, salad and spinach most contaminated. — 6659 vegetables and fruits in 29 cross-sectional studies, Ethiopia, 2010-2025 (n = 6659) Evidence C source
  Overall contamination 48.76% (95% CI 40.78-56.74)
• In 153 adults starting leukemia chemotherapy, banning raw fruit and vegetables did not reduce major infections, 29% versus 35% on a raw diet. — 153 patients with newly diagnosed acute myeloid leukemia in HEPA-filtered rooms during induction therapy, all on antimicrobial prophylaxis (n = 153) Evidence B source
  Major infection 29% cooked vs 35% raw (P=0.60), similar time to infection and survival

What people believe that the data does not support

• A review of 28 studies found 9 of 11 linked raw vegetables with lower upper digestive tract cancers, against only 4 of 11 for cooked vegetables. — 28 observational studies 1994-2003 on raw and cooked vegetables and cancer (n = 28 studies) Evidence C source
  Significant inverse association in 9 of 11 studies for raw vs 4 of 11 for cooked (oral, pharyngeal, laryngeal, esophageal, gastric cancers)
• The FDA allows a health claim linking diets high in fruits and vegetables with lower cancer risk, but the claim may not state any degree of risk reduction. — US food labels Evidence E source
  Authorized claim without a quantified effect

Who this works differently for

• Among 152 preschoolers served broccoli for 7 weeks, bitter-sensitive children ate 80% more with dressing than plain, while dip did not help bitter-insensitive children. — 152 mostly Hispanic preschoolers in Head Start classrooms, raw broccoli twice weekly for 7 weeks (n = 152) Evidence B source
  80% more broccoli with dressing in bitter-sensitive children (P<0.001), no effect in insensitive children
• Among 50 adults with inflammatory bowel disease, raw vegetables were named in 10.9% of reports of foods that worsen symptoms, while cooked vegetables were among foods that eased them. — 50 adults with Crohn's disease or ulcerative colitis, Istanbul outpatient clinic (n = 50) Evidence C source
  Raw vegetables 10.9% of worsening foods, cooked vegetables 18.2% of relieving foods

The bottom line

Cooking and fat change what you absorb. In 16 young men, adding 5.3 oz (150 g) of scrambled egg to a raw mixed salad raised absorption of alpha-carotene, beta-carotene and lycopene 3 to 8 fold in single meals. In 8 women eating carrots and spinach for 4 weeks, the processed vegetables raised plasma beta-carotene about three times more than raw ones. That difference did not reach significance (P = 0.09), and allocation was not described as random. Cooking also costs some vitamin C. Among 447 Spanish adults, counting home cooking lowered the modeled vitamin C intake from vegetables by 12.5 percent. The cancer case for raw over cooked is old and thin. A 2004 review counted 9 of 11 studies linking raw vegetables with lower upper digestive tract cancers against 4 of 11 for cooked, mostly case-control studies with no pooled estimate. The FDA health claim on fruits, vegetables and cancer may not state any size of risk reduction. In 429,886 UK Biobank adults followed 12.6 years, raw and cooked vegetables were each linked with lower risk of type 2 diabetes and death, with no hazard ratios in the abstract. The real caution is contamination. Pooled sampling studies found parasites on about 6.7 percent and enteric viruses on about 7.9 percent of vegetable samples, lettuce above all, and that is presence on produce, not a rate of illness. In Ethiopian farm and market samples about half of raw vegetables and fruits carried bacteria or parasites, which does not carry over to washed produce elsewhere. Among 50 adults with Crohn's disease or ulcerative colitis, raw vegetables made up 10.9 percent of the foods named as worsening symptoms, while cooked vegetables were among those named as easing them. In a classroom trial of 152 preschoolers, children sensitive to bitterness ate 80 percent more broccoli with dressing than plain.

Sources

1. rwvg-r3-01 · reference dataset
   FNDDS 2709763 Raw vegetable, NFS (75100250): Energy 30 kcal/100 g, 1 cup 120 g 36.0 kcal · Fiber, total dietary 2 g/100 g, 2.4 g · Vitamin C, total ascorbic acid 28.7 mg/100 g, 34.4 mg · Potassium, K 263 mg/100 g, 315.6 mg · Vitamin A, RAE 206 ug/100 g, 247.2 ug
   USDA FNDDS 2021-2023 · checked 2026-09-29
2. rwvg-r3-02 · controlled crossover trial
   Daily consumption of processed carrots and spinach over a 4-wk period produced an increase in plasma beta-carotene concentration that averaged three times that associated with consumption of the same amount of beta-carotene from these vegetables in the raw form (P = 0.09).
   J Nutr, 1998 · checked 2026-09-29
3. rwvg-r3-03 · randomized crossover trial
   the TRL AUC(0-10h) of carotenoid not present in eggs, including α-carotene, β-carotene, and lycopene, increased 3-8-fold (P < 0.01) for the HE meal compared with the control meal.
   Am J Clin Nutr, 2015 · checked 2026-09-29
4. rwvg-r3-04 · cross-sectional
   The largest decreases of vitamin C, when cooking techniques were considered, were observed in legumes (- 88.0%), tubers (- 62.7%), and vegetables (- 12.5%). The main source of between-person variability in vitamin C intake from vegetables and tubers was raw vegetables and boiled potatoes, respectively.
   Eur J Nutr, 2026 · checked 2026-09-29
5. rwvg-r3-05 · cluster randomized trial
   The mean HbA1C in the intervention group decreased 3⋅1 % over 12 weeks while it decreased by 2⋅3 % in the control group (P = 0⋅009).
   J Nutr Sci, 2022 · checked 2026-09-29
6. rwvg-r3-06 · prospective cohort
   Higher intake of raw and cooked vegetables was significantly associated with lower risks of disease progression from diabetes-free state to incident T2D and to total death.
   Eur J Nutr, 2024 · checked 2026-09-29
7. rwvg-r3-08 · meta-analysis of prevalence
   The mean occurrence rates of parasites and viruses were 0.067 (95 % CI: 0.056-0.080) and 0.079 (95 % CI: 0.054-0.113), respectively.
   Food Res Int, 2022 · checked 2026-09-29
8. rwvg-r3-09 · meta-analysis of prevalence
   The overall prevalence of contaminated fresh produce was 48.76% (95% CI: 40.78–56.74).
   BMC Infect Dis, 2025 · checked 2026-09-29
9. rwvg-r3-10 · randomized controlled trial
   Twenty-nine percent of patients in the cooked group and 35% of patients in the raw group developed a major infection (P = .60).
   J Clin Oncol, 2008 · checked 2026-09-29
10. rwvg-r3-07 · review of observational studies
    Nine of the 11 studies of raw and cooked vegetables showed statistically significant inverse relationships of these cancers with raw vegetables, but only 4 with cooked vegetables.
    Cancer Epidemiol Biomarkers Prev, 2004 · checked 2026-09-29
11. rwvg-r3-11 · authorized health claim
    (E) The claim does not attribute any degree of cancer risk reduction to diets low in fat and high in fruits and vegetables;
    21 CFR 101.78, Health claims: fruits and vegetables and cancer · checked 2026-09-29
12. rwvg-r3-12 · cluster-randomized trial
    Bitter-sensitive children, however, ate 80% more broccoli with dressing than when served plain (P<0.001)
    J Acad Nutr Diet, 2012 · checked 2026-09-29
13. rwvg-r3-13 · cross-sectional
    Most patients (82%) reported consuming foods that worsened their symptoms, primarily legumes (21%), milk (14.3%), and raw vegetables (10.9%). Conversely, 50% identified foods that alleviated symptoms, mainly yogurt (18.2%) and cooked vegetables (18.2%), cooked meat (7.6%).
    BMC Gastroenterol, 2026 · checked 2026-09-29