Carrot intake is consistently negatively associated with cancer incidence: A systematic review and meta-analysis of prospective observational studies

Ojobor CC, O’Brien GM, Siervo M, Ogbonnaya C, Brandt K · Critical Reviews in Food Science and Nutrition · 2023 December 17

DOI 10.1080/10408398.2023.2287176

Objective

To assess the relationship between carrot intake and cancer incidence, evaluating whether α-carotene, a biomarker of carrot consumption, correlates with reduced cancer risk.

Conclusions

Increased carrot intake and higher plasma α-carotene levels are significantly associated with reduced cancer risk. The summary relative risk (RR) for carrot intake was 0.90, and for α-carotene plasma levels was 0.80, suggesting that carrot consumption may decrease cancer risk. Further research is needed to understand the causal mechanisms.

Critical Appraisal

Does this review establish that eating more carrots prevents cancer?

No. The authors report that higher carrot or dietary α-carotene intake was associated with a lower pooled risk across 50 prospective analyses: relative risk 0.90, with a 95% confidence interval of 0.87–0.94. This represents a relative difference, not a ten-percentage-point reduction in someone’s cancer risk. Measuring diet before subsequent outcomes strengthens the evidence compared with retrospective recall, but does not eliminate differences in smoking, diet and other behaviours. Few studies adjusted for overall vegetable intake. Questions about the outcomes included in the pooling also require resolution before this estimate can confidently be interpreted as an association specifically with cancer incidence.

How directly does the evidence support eating five carrot servings each week?

The proposed quantity comes from a statistical dose–response model, not a trial testing that eating schedule. Only 15 of the 50 intake analyses reported carrots directly; 35 reported dietary α-carotene, which the authors treated as a substitute because carrots supply much of this nutrient. The two groups produced similar pooled estimates, supporting—but not proving—the substitution’s validity. The dose–response analysis associated five 80-gram servings weekly with approximately 20% lower risk. That estimate depends on dietary measurement, nutrient-to-carrot conversions and modelling assumptions. It does not establish a preventive dose, demonstrate that adding carrots produces that benefit, or justify extrapolation to carotene supplements.

Did the pooled studies consistently measure new cases of cancer?

The supplied report raises an important unresolved concern about that claim. Its forest plots include studies described in the references as examining benign uterine fibroids, recurrent colorectal adenomas, breast-cancer survival and cancer mortality. These are not interchangeable with developing a new cancer. Verification against the original studies and extraction dataset is needed to establish exactly which outcomes entered the pooled estimates and whether an incidence-only analysis changes the findings. The reported sensitivity analyses do not specifically resolve this issue. Although the prospective focus and checks for influential studies are strengths, the unavailable supplementary material and uninspected primary-study data limit verification of the review’s central outcome definition.

Assessed 18 Sept 2026.

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Insights

Consuming carrots can significantly decrease the risk of cancer.

The methodology used in this research involved examining the links between carrot intake and the incidence of cancer. The scope was broad, examining all studies published before June 2022 that offered risk estimates connecting cancer incidence with either carrot consumption, α-carotene intake, or α-carotene plasma levels. Possible sources of such studies included those found via digital searches, manually identified within other studies, or garnered from existing reviews. Analysis was carried out comparing the highest and lowest reported intakes from prospective studies, estimating summary relative risks using a random-effects model. The study's results indicated a strong correlation between carrot consumption and a notable reduction in cancer risk. This conclusion was derived from the analysis of 198 observational studies, 50 of which were prospective studies involving a total of 52,000 cases that specifically recorded carrot intake. Comparatively, on the correlation between α-carotene plasma levels and cancer risk, analysis from 30 prospective studies with 9,331 cases indicated that a higher presence of α-carotene also resulted in decreased cancer risk. Despite a moderate variance between studies, these findings serve as significant evidence in support of the anticancer benefits of carrots.