Barbecuing and Genotoxicity

By: Fira Katchan  |  April 21, 2023

By Fira Katchan 

Lag Ba’omer is rapidly approaching, which means a day full of celebrations, bonfires, and especially barbecues. Grilled meat is a delicious food that is enjoyed by all. However, there are some studies that suggest that eating grilled or barbecued meat can be genotoxic and a danger to our health. Is this just public health trying to curb yet another of life’s simple pleasures, or is there fire where there is smoked meat?

There are two main incriminating chemicals formed when muscle meats are cooked at high temperatures especially when cooked over an open flame as in BBQing. These two chemicals are heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Heterocyclic amines are chemicals that are formed when amino acids, sugars, and creatine react at high temperatures. They are mainly found in muscle meats, and they are considered carcinogenic and mutagenic. Examples of HCA’s include PHIP, MelQ, MelQX, and DiMelQX. PAH’s form when fat and juices from the meat cooked over an open fire drip onto the fire, causing flames and smoke. The smoke contains polycyclic aromatic hydrocarbons which then adhere to the surface of the cooking meat, and are then ingested, especially on charred dishes. Examples of PAH’s include naphthalene and anthracene. These same chemicals are found in cigarette smoke and are considered carcinogenic.

I chose to research three questions related to this topic: The first was whether these chemicals are more likely to be found in BBQ’ed meats vs. meats prepared by other means. The second question was to review the assay evidence linking these chemicals to genotoxicity. And the third was to see if human epidemiologic links have been established between BBQ meat consumption and risk of malignancy. Lastly I reviewed whether any preventative measures might be able to mitigate the potential risk of BBQing.

The first topic I researched is if barbecuing foods was more dangerous than other cooking methods, like frying, toasting, and roasting. One study looked at the effects of cooking on the formation of 27 different PAHs in foods prepared in different cooking methods. They found little evidence of PAH formation during frying, roasting, and toasting methods. However, barbecuing meat, especially with charcoal, resulted in the formation of PAHs in most foods.

The next study I looked at focused on heterocyclic amines in cooked meat products. While they acknowledge shortcomings in some of the epidemiological studies, they stated that dietary assessments have exposed a link between well done meat, especially grilled red meat, and increased exposure to HCA’s. They highlight that the link between well-done meat intake and incidence of cancer is stronger than ever, though they stop short of clear, definitive conclusions due to limitations in the data collection.

The second research topic I explored was looking for evidence for genotoxicity of HCA’s and PAH’s. The first study I looked at investigated the effect of 4 HCA’s on freshly isolated human peripheral blood mononuclear cells by the comet assay. They found that PHIP and IQ induced significant DNA damage at low concentrations. MeIQx and DiMeIQx also induced significant DNA damage, but only at higher concentrations. Of note this study also examined the potential preventative effect of adding phenolic extracts derived from olive oil to the comet assays, and found that even a low concentration of phenolic extracts could significantly mitigate the DNA damage observed by HCA’s.

I further researched the genotoxic effects of these chemicals by looking at how they affected welders. By the nature of their work, welders are exposed to a number of hazardous compounds, including polycyclic aromatic hydrocarbons. This particular study looked at DNA damage in welders using comet and micronucleus assays. In this study 48 welders and an equal number of control subjects were evaluated for DNA damage in their lymphocytes using the comet assay. They were also evaluated for genotoxic damage in buccal epithelial cells by the micronucleus assay. The results from the comet test show that the tail intensity in lymphocytes is clearly greater in the welder workers. This means there is more DNA damage seen in their lymphocytes, than in the control group. The results from the micronucleus test show that the welder workers had a higher frequency of micronuclei on their buckle epithelial cells.

The last topic I researched was the epidemiological evidence linking barbecued meat consumption with cancer risk. The first study was a case-control study conducted with 193 cases of pancreatic cancer patients, and 674 control subjects. All subjects were asked to fill in a questionnaire on their meat intake and how it was cooked. The only group that showed a significant difference between the cases and controls was in those that ingested mostly grilled or barbecued meat.

The last epidemiologic study was also a case-control study that examined the meat cooking methods of people diagnosed with colorectal adenomas versus controls. They found that there was an increased risk of colorectal adenomas with higher intake of red meat. Most of this was due to the subgroup of consumers of red meat that was cooked until well done/very well done and/or with very high temperature cooking techniques, such as grilling. These results are consistent with the hypothesis that carcinogenic compounds formed by high-temperature cooking techniques, such as heterocyclic amines and polycyclic aromatic hydrocarbons, may contribute to the risk of developing colorectal tumors.

Based on my review of the research, it is evident that eating too much barbecued meat may lead to genotoxicity and hence increase one’s cancer risk. However, there are some simple measures which may limit the risks. For example, wrapping the meat in tinfoil will prevent the PAHs from adhering to the surface of the meat during BBQing. Another preventative measure against PAHs is to spray the meat with vinegar before grilling. Heating up the meat prior to barbecuing it through another cooking method will reduce the amount of time grilling it, and lastly, consuming green leafy vegetables, such as broccoli, as a side dish may moderate the hazard. Overall, consuming a blackened grilled steak every night is not your best bet if you are worried about cancer. But enjoying the occasional burned burger or grilled steak is not something to worry or stress about.