When it comes to food, much attention is paid to “what” we eat—whether it’s organic, gluten-free, whole, or processed—and rightfully so; the nutritional value of the foods we consume significantly influences our trajectory of health and disease. And yet, the effects of foods extend beyond their inherent nutritional value. The way food is prepared affects its healthfulness. This is an important consideration, especially during the COVID-19 pandemic—when patients may be preparing more meals at home—and as the outdoor grilling season begins.
When preparing meat, certain cooking methods may present health concerns. During high-heat exposures, such as frying, roasting, braising, and grilling meat, potential carcinogens are formed.1-4 Temperature, duration, heat transfer, and added antioxidants are some factors that may affect the formation of these carcinogens.1,2 Increased mutagenic activity has been noted with increased temperatures and time, and with better heat transfer, as seen in cooking methods with direct contact (frying and grilling).1 For inhibition, antioxidant-rich marinades that include herbs commonly used as meat flavoring (garlic, ginger, thyme, and rosemary) may prevent the formation of potential carcinogenic compounds during frying or grilling.5-7
Grilling & Cancer Risk
Small amounts of grilled meat are likely just fine to consume, but for people with a history of cancer and/or high consumption, there are some red flags to consider. Meat, including beef, pork, poultry, or fish, may form carcinogenic chemicals called heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) when charred or cooked over high heat, as on a grill.1,8 Research suggests:
- When the meat’s fat drips into the grill, the resulting flames can cover food with PAHs,9 and inhalation may also contribute to PAH risk, dependent on the degree of exposure.10
- PAHs may also be absorbed through the skin. A 2018 case study in China on the carcinogenicity of PAHs found that in the case of barbeque fumes, dermal absorption was a more important pathway for intake of low-molecular-weight PAHs than inhalation.11
- Regarding risk of cancer development, human studies have not been definitive. A review of epidemiological studies suggested that high exposure to meat carcinogens, particularly HCAs, may increase the risk of human cancer;12 however, studies investigating associations between meat cooking methods and risk of prostate and colorectal cancer did not report significant findings.13,14
In 2015, an independent panel of experts convened by the International Agency for Research on Cancer (IARC) determined that the consumption of red meat is potentially carcinogenic to humans.15 However, IARC did not conclude that HCAs and PAHs were associated with cancer incidence.15
Healthy Tips for Grilling Foods
What specific steps can patients take to improve the healthfulness of grilled meats? The IFM Toolkit contains “A Guide to Grilling Food,” which can be freely downloaded and printed for distribution in your office. It includes some of the following information:
- Go Lean: Instead of grilling fatty burgers or sausages, opt for lean, grass-fed steak, chicken, or fish. Further, removing the skin from poultry before cooking will reduce HCA formation.
- Avoid Charring & Trim Meat: Rotate meat frequently to allow the center to fully cook without overheating the surface. Remove any charred portions of meat, and refrain from using gravy made from meat drippings.
- Use Marinades: Acidic rubs and marinades may help break down some of the muscle in the meat and reduce the number of HCAs on your plate.
Additional Clinical Applications
Toxic chemicals are literally all around us—in the air we breathe, the food we consume, and the items we use for everyday life—but armed with knowledge, people can make choices that limit their exposure.
Beyond healthy tips for grilling, IFM has a wealth of information for clinicians to use as reference when talking to patients about chemicals and food preparation. For example, for IFM members, the following materials are printable and can be distributed to patients in the office:
- Non-Toxic Choices for Food Preparation, Cookware, and Dishes
- A Guide to Cooking with Fats and Oils
- Cooking to Preserve Nutrition
- Gibis M. Heterocyclic aromatic amines in cooked meat products: causes, formation, occurrence, and risk assessment. Compr Rev Food Sci Food Saf. 2016;15(2):269-303. doi:10.1111/1541-4337.12186
- Janoszka B, Nowak A, Szumska M, Śnieśek E, Tyrpień-Golder K Human exposure to biologically active heterocyclic aromatic amines arising from thermal processing of protein rich food. Wiad Lek. 2019;72(8):1542-1550.
- Cheng Y, Yu Y, Zhou X, et al. Heterocyclic amines in braised chicken may mainly infiltrate from reused marinade during braising, instead of thermic generation. J Sci Food Agric. 2020;100(5):1867-1874. doi:10.1002/jsfa.10176
- Hsu KY, Chen BH. Analysis and reduction of heterocyclic amines and cholesterol oxidation products in chicken by controlling flavorings and roasting condition. Food Res Int. 2020;131:109004. doi:10.1016/j.foodres.2020.109004
- Puangsombat K, Smith JS. Inhibition of heterocyclic amine formation in beef patties by ethanolic extracts of rosemary. J Food Sci. 2010;75(2):T40-T47. doi:10.1111/j.1750-3841.2009.01491.x
- Viegas O, Amaro LF, Ferreira IM, Pinho O. Inhibitory effect of antioxidant-rich marinades on the formation of heterocyclic aromatic amines in pan-fried beef. J Agric Food Chem. 2012;60(24):6235?6240. doi:10.1021/jf302227b
- Sepahpour S, Selamat J, Khatib A, Manap MYA, Abdull Razis AF, Hajeb P. Inhibitory effect of mixture herbs/spices on formation of heterocyclic amines and mutagenic activity of grilled beef. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2018;35(10):1911-1927. doi:10.1080/19440049.2018.1488085
- Hamidi EN, Hajeb P, Selamat J, Abdull Razis AF. Polycyclic aromatic hydrocarbons (PAHs) and their bioaccessibility in meat: a tool for assessing human cancer risk. Asian Pac J Cancer Prev. 2016;17(1):15-23. doi:10.7314/apjcp.2016.17.1.15
- Jägerstad M, Skog K. Genotoxicity of heat-processed foods. Mutat Res. 2005;574(1-2):156-172. doi:10.1016/j.mrfmmm.2005.01.030
- Connellan SJ. Lung diseases associated with hydrocarbon exposure. Respir Med. 2017;126:46-51. doi:10.1016/j.rmed.2017.03.021
- Lao JY, Xie SY, Wu CC, Bao LJ, Tao S, Zeng EY. Importance of dermal absorption of polycyclic aromatic hydrocarbons derived from barbecue fumes. Environ Sci Technol. 2018;52(15):8330-8338. doi:10.1021/acs.est.8b01689
- Zheng W, Lee SA. Well-done meat intake, heterocyclic amine exposure, and cancer risk. Nutr Cancer. 2009;61(4):437-446. doi:10.1080/01635580802710741
- Bylsma LC, Alexander DD. A review and meta-analysis of prospective studies of red and processed meat, meat cooking methods, heme iron, heterocyclic amines and prostate cancer. Nutr J.2015;14:125. doi:10.1186/s12937-015-0111-3
- Le NT, Michels FA, Song M, et al. A prospective analysis of meat mutagens and colorectal cancer in the Nurses’ Health Study and Health Professionals Follow-up study. Environ Health Perspect.2016;124(10):1529-1536. doi:10.1289/EHP238
- National Cancer Institute. Chemicals in meat cooked at high temperatures and cancer risk. Reviewed July 11, 2017. Accessed May 4, 2020. https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet – r1
IFM Board President of Clinical Affairs Mark Hyman, MD, is releasing a new cookbook entitled Food: What the Heck Should I Cook? The book focuses on a few key principles from the pegan (paleo/vegan) diet and helps readers learn how to create health by cooking with real whole foods.Read More