Do citrus fruits increase the risk of skin cancer? Original paper

Psoralen, a compound in citrus fruits, may increase the skin’s sensitivity to light and thereby the risk of melanoma, a type of skin cancer.

This cohort study assessed the associations between melanoma risk and the intake of citrus fruits.

The ≈500,000 participants in the UK Biobank cohort^[1] completed 24-hour food recalls evaluating the frequency and type of citrus intake (clementines, grapefruits, mandarines, oranges, satsumas, grapefruit juice, and orange juice).

The authors used national registries to assess melanoma cases. Out of 198,964 people, 1,592 developed skin cancer.

The odds of melanoma were 63% higher in people consuming more than 2 daily servings of citrus products than in people not consuming any.

Oranges and orange juice were the only individual citrus products associated with a higher risk of melanoma: the odds of melanoma were higher in people consuming more than one daily serving of oranges (+79%) or orange juice (+54%).

There was a linear association between citrus consumption and melanoma risk in people with fair or very fair skin: those consuming more than 2 daily servings had 75% higher odds of developing melanoma.

The odds of melanoma were 52% lower in people with “olive” skin consuming 0–0.5 daily servings of citrus products than in those not consuming any.

Other studies assessing the association between melanoma and citrus fruits had mixed results. Some cohort studies found a linear association,^[2][3] while others found no association.^[4][5]

Moreover, it is unclear at present which compounds in citrus fruits would be responsible for a reduction in the odds of melanoma, though a mouse study attributed a chemopreventive effect to the bioflavonoid hesperidin.^[6]