Exposure to fumes from frying with animal or vegetable fats increases the risk of lung cancer. For workers in restaurant kitchens, canteens, fast-food outlets, fry shops, etc., the threat is concrete, warns the French Agency for Food, Environmental and Health Safety at Work (ANSES) in a document on carcinogenic processes affecting certain professional categories and changes to national legislation on the matter. (1)
Fried Food and IPA
While frying, the increase in temperature promotes physical and biochemical transformations of fats and foods, including the breakdown of fatty acid esters present in oils or fats into volatile or semi-volatile organic compounds that can condense into fine (PM2,5) and ultrafine (PM0,1) particles, capable of penetrating the body.
The emissions frying also contain organic compounds with mutagenic or carcinogenic properties, such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines and acrylamide.
Known but overlooked occupational hazards
The Monograph 95/2010 of IARC (the International Agency for Research on Cancer) has classified work that is exposed to emissions from high-temperature frying in group 2A (probably carcinogenic to humans). (2)
The classification of IARC is based on:
– evidence of carcinogenicity in humans (for lung cancer), based on 4 scientific studies, only one of which took into account co-exposure to the fumes of the fuels used;
– experimental and mechanistic evidence such as:
- the induction of lung tumors in rodents exposed to emissions from high-temperature frying with unrefined rapeseed oil;
- evidence of a low genotoxic potential of frying emissions when cooking oils were heated below 100°C and a high genotoxic potential when heated above 230°C.
12 new evidences
In the 15 years since the IARC monograph, new epidemiological publications have appeared on the carcinogenic risk of emissions from high-temperature frying.
ANSES conducted a literature review and assessed 12 studies as interesting:
– five case-control studies, one cohort study and two meta-analyses related to the risk of bronchopulmonary cancer;
– three case-control studies related to the risks of precancerous lesions of the cervix, nasopharyngeal cancer and oral cancer;
– a cohort study linked to colorectal cancer and breast cancer risks.
Studies on bronchopulmonary cancer were considered consistent with those underlying the IARC Monograph, therefore valid as confirmation of the carcinogenic nature of high-temperature frying emissions on the lungs. Those indicating a relationship with a carcinogenic impact on other target organs were instead considered unsuitable for drawing conclusions.
How frying emissions vary
The composition of the fumes of fried foods varies depending on some variables:
– type of frying of the three methods examined, deep frying emits more fine and ultrafine particles and PAHs than stir-frying or pan-frying;
– the fat used. This element influences the chemical composition of frying emissions more strongly than the type of frying. Studies show that the worst are rapeseed oil, followed by olive oil, peanut oil and soybean oil (Yao et al. 2015);
– the frying temperature higher it is, the more it favors the emission of volatile organic compounds;
– cooking time. Long frying promotes PAH emissions;
– the type of fried foods. Frying fatty foods promotes PAH emissions;
– the energy source used for cooking gas emits more ultrafine particles and PAHs than electric cooking.
Protective measures
ANSES stresses that
– the protection of kitchen workers exposed to PAHs and particles from frying emissions can be reduced by installing a fume extraction system;
– the COLCHIC database on occupational exposure to chemical agents contains very little data on this specific risk, ‘thus reflecting a lack of concern in France about frying emissions’;
– scientific publications assessing worker exposure to PAHs during frying operations ‘are mainly conducted in Asia, also reflecting the lack of concern about occupational exposures to frying emissions more generally in the West’.
The urgency of preventing occupational diseases
Millions of workers in the EU work in restaurant kitchens (over 1.400.000 French at the end of 2021). Ignoring this occupational risk today means spreading serious illness in the coming years.
ANSES proposes to add to the French decree establishing the list of carcinogenic substances, mixtures and processes the title ‘work that exposes to emissions from frying with animal or vegetable fats‘. And in the rest of European kitchens?
Marta Strinati
Footnote
(1) Anses. (2024). Avis of the National Agency for Health Care, Food, Environment and Labor relating to the identification of labor or procedures for registering in the list of substances, mixtures and cancer procedures – Expertise relating aux travaux ou procédés exposant aux hydrocarbures aromatices polycycliques (HAP) (saisine 2017-SA-0237). Maisons-Alfort : Anses, 12p. https://www.anses.fr/fr/system/files/VSR2017SA0237Ra-4.pdf
(2) Household Use of Solid Fuels and High-temperature Frying. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 95. IARC 2010 https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Household-Use-Of-Solid-Fuels-And-High-temperature-Frying-2010
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
