Table 1.

Studies that compared raw and cooked vegetable intake and cancer risk

Author countryCancer siteOR (95% CI)VegetableComparison of quantity of intakeRaw/cooked vegetablesNo. subjects
Levi et al. (7) SwitzerlandOral and pharyngeal0.3 (0.16–0.58)Raw>8.5 vs ≤5.0 servings/wk156 cases, 284 controls
0.14 (0.07–0.19)Cooked>8.6 vs ≤5.2 servings/wk
Franceschi et al. (8) ItalyOral and pharyngeal0.4 (0.3–0.6)Raw>14.1 vs ≤5 servings/wk598 cases, 1,491 controls
0.5 (0.3–0.7)Cooked>4.5 vs ≤1.5 servings/wk
De Stephani et al. (10) UruguayLaryngeal-male0.29 (0.15–0.56)Raw>31 vs ≤8.6 g/dCarrot, lettuce, tomato148 cases, 444 controls
0.96 (0.5–1.84)Cooked>87.7 vs ≤35.5 g/dOnion, Swiss chard, spinach, winter squash, cabbage, cauliflower, zucchini, red pepper
Bosetti et al. (9) Italy and SwitzerlandLaryngeal0.22 (0.14–0.34)Raw>13.9 vs ≤5.4 servings/wk527 cases, 1,297 controls
0.32 (0.21–0.49)Cooked>5.1 vs ≤1.6 servings/wk
Bosetti et al. (18) northern ItalyEsophageal0.32 (0.19–0.55)Raw>12.6 vs ≤3.9 servings/wk304 cases, 743 controls
0.79 (0.47–1.31)Cooked>4.3 vs ≤1.4 servings/wk
De Stefani et al. (19) UruguayEsophageal0.52 (0.27–0.99)Raw≥34.4 vs ≤8 g/d111 cases, 444 controls
0.55 (0.29–1.03)Cooked≥95.5 vs ≤36.1 g/d
Levi et al. (20) SwitzerlandEsophageal0.14 (0.1–0.4)Raw>9.5 vs ≤5.5 servings/wk101 cases, 327 controls
0.19 (0.1–0.3)Cooked>8.0 vs ≤5.3 servings/wk
Cornee et al. (25) FranceGastric0.41 (0.19–0.88)RawTomato, lettuce, radish, cucumber, celery92 cases, 128 controls
1.06 (0.53–2.13)CookedSwiss chard, spinach, cabbage, cauliflower, courgette, beetroot, green beans, peas, eggplant, leek, mushrooms
Botterweck et al. (26) the Netherlands*Gastric0.81 (0.55–1.19)RawMedian intake 74 vs 8 g/d310 cases, 3,346 controls
0.79 (0.55–1.14)CookedMedian intake 213 vs 79 g/d
De Stefani et al. (27) UruguayGastric0.52 (0.31–0.86)Raw≥29.5 vs ≤9.0 g/dCarrot, lettuce, tomato160 cases, 320 controls
0.93 (0.57–1.51)Cooked≥90.0 vs ≤53.0 g/dOnion, garlic, Swiss chard, spinach, winter squash, beetroot, cabbage, cauliflower, zucchini, red pepper
Kim et al. (28) KoreaGastric0.55 (0.28–1.09)Raw136 cases, 136 controls
0.98 (0.50–1.90)Cooked
Centonze et al. (36) southern ItalyColorectal0.67 (0.35–1.29)Raw≥76 vs ≤46 g/dSalad, celery, tomato, carrot119 cases, 119 controls
0.59 (0.31–1.12)Cooked≥267 vs ≤183 g/dVegetable soup, spinach, beet, endive, eggplant, artichoke, green pepper, zucchini, cauliflower, peas, kidney beans, runner beans
Franceschi et al. (38) ItalyColon0.7 (0.7–0.8)Raw>12 vs ≤4.0 servings/wk1,225 cases, 4,154 controls
0.7 (0.6–0.8)Cooked>7.3 vs ≤2.9 servings/wk
Rectal and rectosigmoid0.8 (0.7–1.0)Raw>12 vs ≤4.0 servings/wk728 cases, 4,154 controls
0.7 (0.7–0.8)Cooked>7.3 vs ≤2.9 servings/wk
Boutron-Ruault et al. (39) FranceColorectal1.0 (0.5–1.8)Raw171 cases, 202 controls
0.8 (0.4–1.5)Cooked
Levi et al. (40) SwitzerlandColorectal0.49 (0.3–0.78)Raw>9 vs ≤5.5 servings/wk223 cases, 291 controls
0.41 (0.26–0.66)Cooked>8.75 vs ≤5.25 servings/wk
Voorips et al. (41) the Netherlands*Colon-male0.79 (0.54–1.16)RawMedian intake 73 vs 7 g/dEndive, carrot, tomato, lettuce313 cases, 1,456 subcohort
0.94 (0.64–1.39)CookedMedian intake 234 vs 79 g/dBrussels sprouts, cauliflower, cabbage, spinach, endive, beetroot, string beans, broad beans, kale, carrot, sweet pepper, sauerkraut, rhubarb, mushroom, gherkin
Colon-female1.02 (0.67–1.54)RawMedian intake 76 vs 10 g/d274 cases, 1,497 subcohort
0.75 (0.49–1.14)CookedMedian intake 229 vs 80 g/d
Rectal-male0.93 (0.58–1.47)RawMedian intake 73 vs 7 g/d201 cases, 1,456 subcohort
0.96 (0.61–1.51)CookedMedian intake 234 vs 79 g/d
Rectal-female1.24 (0.67–2.26)RawMedian intake 76 vs 10 g/d122 cases, 1,497 subcohort
1.34 (0.74–2.42)CookedMedian intake 229 vs 80 g/d
Deneo-Pellegrini et al. (42) UruguayColorectal0.8 (0.6–1.0)RawCarrot, tomato, lettuce484 cases, 1,452 controls
0.9 (0.7–1.2)CookedOnion, Swiss chard, spinach, potato, sweet potato, winter squash, cabbage, cauliflower, zucchini, red pepper, kidney bean, lentil
Mayne et al. (44) New YorkLung-male (nonsmokers)0.41Raw212 cases, 212 controls
1.02§Cooked
Lung-female (nonsmokers)0.40Raw201 cases, 201 controls
0.69§Cooked
Voorips et al. (46) the Netherlands*Lung0.7 (0.6–1.0)RawMedian intake 74 vs 8 g/dEndive, carrot, lettuce, tomato1,010 cases, 2,953 subcohort
0.8 (0.6–1.1)CookedMedian intake 231 vs 79 g/dBrussels sprouts, cauliflower, cabbage, spinach, endive, beetroot, string beans, broad beans, kale, carrot, sweet pepper, sauerkraut, rhubarb, mushroom, gherkin
De Stefani et al. (45) UruguayLung-male0.97 (0.64–1.45)RawCarrot, lettuce, tomato200 cases, 600 controls
0.50 (0.32–0.76)CookedOnion, Swiss chard, spinach, winter squash, potato, sweet potato, cabbage, cauliflower, zucchini, red pepper, kidney bean, lentil
Franceschi et al. (49) ItalyBreast0.73 (0.6–0.88)Raw>12.5 vs ≤4.9 servings/wkLettuce-like salad, carrot, tomato, mixed salad2,569 cases, 2,588 controls
0.96 (0.79–1.16)Cooked>7.5 vs ≤3.1 servings/wkPulses, carrot, onion, artichoke, Cruciferae, spinach, zucchini, pepper, eggplant, savory pie, vegetable soup
Ronco et al. (50) UruguayBreast0.51 (0.33–0.79)Raw>6.5 vs <2.7 servings/wk400 cases, 405 controls
0.58 (0.36–0.94)Cooked>9.8 vs <6.3 servings/wk
Adzersen et al. (51) GermanyBreast0.51 (0.31–0.84)Raw>65.0 vs <23.7 g/dMixed salads, fresh herbs, green leafy salads, tomatoes, cucumbers, red/green peppers, carrots, radishes, cabbage, sprouts
1.26 (0.77–2.06)Cooked>45.5 vs <18.3 g/dPulses, other cooked vegetables not specified
Bosetti et al. (54) ItalyOvarian0.47 (0.34–0.64)Raw>11.5 vs ≤6.5 servings/wk1,031 cases, 2,411 controls
0.65 (0.48–0.87)Cooked>5.0 vs ≤1.8 servings/wk
McCann et al. (53) New YorkEndometrial0.6 (0.3–0.9)Raw>120 vs ≤54 times/mo232 cases, 639 controls
0.5 (0.3–0.8)Cooked>111 vs ≤61 times/mo
Schuurman et al. (55) the Netherlands*Prostate0.96 (0.68–1.32)RawMedian intake 73 vs 7 g/d704 cases, 1,688 controls
0.85 (0.61–1.19)CookedMedian intake 234 vs 79 g/d
Balbi et al. (56) UruguayBladder1.15 (0.74–1.80)RawMean intake, cases 27.9 g/d, controls 26.6 g/dCarrot, tomato, lettuce144 cases, 576 controls
0.53 (0.32–0.87)CookedCases 68.7 g/d, controls 58.9 g/dOnion, Swiss chard, spinach, winter squash, cabbage, cauliflower, zucchini, red pepper
Zeegers et al. (57) the Netherlands*Urothelial0.94 (0.69–1.27)Raw≥193 vs <99 g/d619 cases, 3,346 subcohort
1.01 (0.75–1.37)Cooked≥58 vs <16 g/d
  • * RRs and 95% CIs calculated in these studies.

  • Represents raw versus cooked fruits and vegetables.

  • 95% CI does not include 1.0.

  • § 95% CI crosses 1.0.

  • Within the highest and lowest quantiles.