Barbecuing over glowing coals and smoking meat and fish products increase the level of pollutants in food. In the process, polycyclic aromatic hydrocarbons (PAHs) – benzpyrene, benzfluorene – are formed in elevated quantities on the surface of the meat or fish when the fuel is burned. Originally, these substances are only present in small amounts in food. They get into the food with the smoke during smoking, and during grilling they are formed from fats due to high temperature exposure and insufficient distance from the heat source. Such hydrocarbons are considered carcinogenic (cancer-causing) and can cause changes in our genetic makeup. They promote the development of stomach and pancreatic carcinoma (cancer of the pancreas). At rising temperatures of 400 °C and above, aromatic hydrocarbons are formed to a high degree. In particular, open fires and melting fat dripping onto the heat source support their formation. Other pollutants produced by grilling protein-rich foods are:
- Acrylamide (Group 2A carcinogen) – is metabolically activated to glycidamide, a genotoxic metabolite; an association between exposure to acrylamide and risk of estrogen receptor-positive mammary carcinoma (breast cancer) has been demonstrated. Acrylamide is formed when starches are overheated, i.e., during baking, frying, roasting, grilling, and deep-frying. When foods containing potatoes and cereals are heated dry above 180 °C, a particularly large amount of acrylamide is formed. Crispbread, French fries, potato chips, and also coffee, contain high amounts of acrylamide.Genetic glycidamide signatures showed high accumulation in bronchial carcinoma (lung cancer) (88% of the tumors examined), and tumors of the liver (73%), kidneys (over 70%), bile ducts (57%), and cervix uteri (50%). According to the EU regulation, as of April 11, 2018, a guideline value of 500 µg/kg applies to French fries (ready-to-eat), 350 µg/kg for cookies and 400 µg/kg for roasted coffee.
- Heterocyclic aromatic amines (HAA) – are formed exclusively during heating (> 150 °C) of food (especially meat and fish) and are considered carcinogenic. HAA develop mainly in the crust. The more browned the meat, the more HAA are formed. Individuals who have a high intake of HAAs have a 50 percent higher risk of developing polyps (adenomas) of the colon (large intestine), which are often precancerous lesions (precursors) for colon carcinoma (colon cancer).
- Also carcinogenic are nitrosamines, which are formed at high temperatures from the reaction of nitrite with secondary amines. This is especially true of cured meat, because high concentrations of nitrosamines develop during heating due to the nitrite curing salt contained. Nitrosamines have genotoxic (substances or effects that can damage the genetic material of organisms) and mutagenic (substances that trigger mutations or chromosomal aberrations) effects. They promote the development of esophageal (esophagus), stomach, pancreatic (pancreas) and liver carcinomas.
- Advanced Glycation Endproducts (AGEs) – AGEs are advanced glycation endproducts; these are the result of a non-enzymatic reaction of carbohydrates with proteins. Non-enzymatic glycation has direct effects on nucleotides and DNA, expressed in the form of DNA mutations as a result of direct damage and in the activation of defective or vulnerable recombination and repair systems. Furthermore, AGEs favor the development of inflammation (inflammation), oxidative stress and insulin resistance (reduced effectiveness of the body’s own insulin at the target organs skeletal muscle, adipose tissue and liver).
Note when grilling:
- Prepare the grilled food gently! It is best to grill once briefly hot and then finish grilling on the edge, where there is less heat.
- If possible, no fat should drip into the embers. By igniting the fat form increased polycyclic aromatic hydrocarbons (PAH), which are deposited by the smoke on the grilled food. Grilling in aluminum trays is recommended. This means that little or no fat drips into the embers and the food is protected from smoke. Caution: If aluminum trays are used, the marinade should not be acidic, because the acid dissolves the aluminum.
- Grilling on gas and electric grills is less harmful to health than using a charcoal grill. Less polycyclic aromatic hydrocarbons (PAHs) are formed.
- Only grill when the charcoal is no longer burning, so a white layer of ash has formed.
- The addition of onions, garlic and spices such as rosemary, thyme, ginger or cayenne pepper can reduce the formation of heterocyclic aromatic amines (HAA) due to their antioxidant effect.
