Consumer exposure to inorganic arsenic in food raises health concerns such as skin cancer, according to the European Food Safety Authority (EFSA).

In a risk assessment, EFSA considered the increase in skin cancers associated with inorganic arsenic exposure as the most relevant harmful effect. Experts concluded that ensuring protection against skin cancer will also be protective against other potential effects.

EFSA calculates a margin of exposure (MOE) for consumers when assessing genotoxic and carcinogenic substances unintentionally in the food chain. This is a ratio of the dose at which a small but measurable adverse effect is observed and the level of exposure to a substance for a given population. A low MOE represents a greater risk than a higher one.

based on data from human studies, an MOE of 1 or less would correspond to an exposure level to inorganic arsenic that might be associated with an increased risk of skin cancer. In adults, the MOEs are low – ranging between 2 and 0.4 for average consumers and between 0.9 and 0.2 for high consumers. Experts said they were 69 percent certain that high consumers of inorganic arsenic may have an increased risk of developing skin cancer.

Arsenic is a contaminant that is present naturally and as a result of human activity. Food is the main source of exposure to inorganic arsenic for people in Europe. The main contributors to dietary exposure are rice, rice-based products, and grains and grain-based products. Drinking water also contributes, although levels are usually low in Europe.

Association with certain cancers

Findings confirm results from EFSA’s previous assessment of the risks linked to inorganic arsenic in food from 2009. EFSA’s Panel on Contaminants in the Food Chain (CONTAM) concluded the minimum amount of inorganic arsenic that produced a low-level health risk lied between 0.3 and 8 µg/kg of body weight (bw) per day.

The European Commission asked EFSA for an updat considering new studies on toxic effects. EFSA consulted with stakeholders on its draft opinion and considered comments.

In the latest work, the ConTAM Panel concluded that low to moderate exposure to inorganic arsenic can cause some cancers and other issues such as stillbirth, congenital heart disease, neurodevelopmental effects, respiratory disease, chronic kidney disease, decreased birth weight, and skin lesions.

Epidemiological studies showed the chronic intake of inorganic arsenic via diet or drinking water was associated with an increased risk of cancers of the skin, bladder, and lungs. 

EFSA’s assessment established a reference point of 0.06 µg/kg bw per day based on a case-control study on skin cancer. This is an estimate of the lowest dose that could be associated with increased induction of skin cancer after exposure to inorganic arsenic and is lower than the 2009 figure.

Dietary exposure estimates for inorganic arsenic were 0.03 to 0.15 μg/kg bw per day for average and 0.07 to 0.33 μg/kg bw per day for European high-level adult consumers.

A risk assessment of combined exposure to inorganic and organic arsenic will be available by 2025.