Cooking Oils and Cancer

Cooking Oil Smoke Point and Cancer

A cooking oil's smoke point is the temperature at which it begins to smoke visibly when heated. When an oil starts smoking it is oxidizing and could damage your body. 

A smoke point is the maximum safe cooking temperature. You should avoid heating the oil past this temperature. If you do heat past the smoke point you increase the risk of the oil turning brown, forming oxidized chemicals that can harm your body and increase your risk of cancer. People who work in kitchens and restaurants with cooking oils and poor ventilation have an increased lung cancer, colorectal cancer, and breast cancer risk.

Each oil manufacturer has a different chemical composition because of processing methods and each batch of fruit, vegetable and seed will vary. These factors will affect the smoke point. 

 Just because you can cook or fry in oil at a high temperature doesn't mean it's a safe option. Cooking meat above 300F/149C creates carcinogens. Cooking or frying carbohydrates like potatoes and breads (donuts) above 350F/177C causes the formation of carcinogen acrylamide. 

The worst type of oil cooking

Prolonged heating of cooking oils produces chemicals such as aldehydes, heterocyclic amines, polycyclic aromatic hydrocarbons, free fatty acids, and acrylamide which can alter cellular metabolism and contribute to cancer. The longer the oil is heated and the higher the temperature the greater the concern. Oil smoking and turning dark are a couple of signs the oils are going bad.

Deep frying foods is associated with an increased risk of several cancers. I have them listed in a comment. In the U.S. the most common source of these foods comes from fast food restaurants. These oils may be used for days.

Reusing vegetable cooking oils is associated with BRCA1 breast cancer mutations.

Pan frying and stir-frying foods at moderate temperatures, in well-ventilated areas, don’t seem to be associated with significant risks of cancer. 

Cooking foods at Temperatures above 350F/177C increases the risks of 

• breast cancer
• breast cancer metastasis
• colorectal cancer
• pancreatic cancer
• prostate cancer
• lung cancer
• bladder cancer
• colon cancer
• rectal cancer
• Non-Hodgkins lymphoma 
• kidney cancer (renal cancer)
• gastric cancer
• esophagus cancer (esophageal cancer)
• liver cancer 

Deep fried foods are Cancer Tactic Not Approved. 

Pan fried at home foods are probably safer. Remember keep the temperature below 350F/177C. 

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Reference Sources Include

Edible Oil Smoke & Flash Points [TEMPERATURE CHART] (centrafoods.com) accessed 04/11/2023. 

Rani L, Kumar M, Kaushik D, et al. A review on the frying process: Methods, models and their mechanism and application in the food industry. Food Res Int. 2023;172:113176. doi:10.1016/j.foodres.2023.113176

Lin PC, Peng CY, Pan CH, et al. Risk of two common glandular cell-type cancers (breast and colorectal cancers) in Chinese occupational chefs: a nationwide ecological study in Taiwan. Int Arch Occup Environ Health. 2021;94(6):1363-1373. doi:10.1007/s00420-021-01673-3 Risk of two common glandular cell-type cancers (breast and colorectal cancers) in Chinese occupational chefs: a nationwide ecological study in Taiwan | SpringerLink  

Xue Y, Jiang Y, Jin S, Li Y. Association between cooking oil fume exposure and lung cancer among Chinese nonsmoking women: a meta-analysis. Onco Targets Ther. 2016;9:2987-2992
https://doi.org/10.2147/OTT.S100949 

Stott-Miller M, Neuhouser ML, Stanford JL. Consumption of deep-fried foods and risk of prostate cancer. Prostate. 2013;73(9):960-969. doi:10.1002/pros.22643

Ganesan K, Xu B. Deep frying cooking oils promote the high risk of metastases in the breast-A critical review. Food Chem Toxicol. 2020;144:111648. doi:10.1016/j.fct.2020.111648

Rajendran P, Alzahrani AM, Rengarajan T, Veeraraghavan VP, Krishna Mohan S. Consumption of reused vegetable oil intensifies BRCA1 mutations. Crit Rev Food Sci Nutr. 2022;62(5):1222-1229. doi:10.1080/10408398.2020.1837725 Consumption of reused vegetable oil intensifies BRCA1 mutations: Critical Reviews in Food Science and Nutrition: Vol 62, No 5 (tandfonline.com)

Zhong GC, Zhu Q, Gong JP, et al. Fried food consumption and the risk of pancreatic cancer: A large prospective multicenter study. Front Nutr. 2022;9:889303. Published 2022 Jul 22. doi:10.3389/fnut.2022.889303

Reng Q, Zhu LL, Feng L, et al. Dietary meat mutagens intake and cancer risk: A systematic review and meta-analysis. Front Nutr. 2022;9:962688. Published 2022 Sep 23. doi:10.3389/fnut.2022.962688

Chemicals in Meat Cooked at High Temperatures and Cancer Risk - NCI