If you’re a UK resident, you’ve probably been sadly disappointed with the number of so-called Summer days which are conducive to getting out the BBQ. But, whilst reflecting on some happy grilling times gone by, it might be appropriate to consider some disturbing information regarding health concerns related to this outdoor craving and possibly adjusting your BBQ techniques for 2016 and beyond.
In addition to the many precautions which do need to be observed around a white-hot grill, I expect the great majority of us do have worries about ensuring we have fully cooked the meat and thereby reduced the risk of inflicting our guests and family with upset tummies or even food poisoning. But overcooking might just have more serious implications.
When meat, such as beef, pork, fish, or poultry, is cooked using a high-temperature process which includes the use of an open flame (1), two key chemicals are produced, - heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Both of these substances are known to be carcinogenic. HCAs are formed when amino acids, sugars, and creatine react at high temperatures. Barbecued chicken and steak all have high concentrations of HCAs. PAHs are formed when fat and juices from meat grilled directly over an open fire drip onto the fire, causing flames. These flames contain PAHs that then adhere to the surface of the meat.
HCAs and PAHs are capable of damaging DNA only after they are metabolised by specific enzymes in the body, in particular, CYP1A2 (Cytochrome P450) which is actually essential for drug metabolism and the breakdown of a number of toxic substances. Several studies have shown that the levels of this enzyme are higher in some individuals than others. Where there is a higher activity of these enzymes, there is greater ‘bioactivation’ of HCAs and PAHs and such persons may be more susceptible and at greater risk (2-4).
Other studies have shown that exposure to HCAs and PAHs can cause cancer in animals (5). However, the doses of HCAs and PAHs used in these studies were very high—equivalent to thousands of times the doses that a person would consume in a normal diet. Population studies have not established a definitive link between HCA and PAH exposure from cooked meats and cancer in humans. However, researchers found that high consumption of well-done, fried, or barbecued meats was associated with increased risks of colorectal (6), pancreatic (7, 8), and prostate (9, 10) cancer. Researchers in the United States are currently investigating the association between meat intake, meat cooking methods, and cancer risk. On-going studies include the NIH-AARP Diet and Health Study (6, 12), the American Cancer Society’s Cancer Prevention Study II (13), the Multiethnic Cohort (14), and studies from Harvard University (15). Similar research in a European population is being conducted in the European Prospective Investigation into Cancer and Nutrition (EPIC) study (16).
In the USA there are currently no Federal guidelines which address the consumption of foods containing HCAs and PAHs. The National Cancer Institute (USA) has produced a number of guidelines which it recommends should be followed to reduce the risks.
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(16) Rohrmann S, Zoller D, Hermann S, Linseisen J. Intake of heterocyclic aromatic amines from meat in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort. British Journal of Nutrition 2007; 98(6):1112–1115.
Grateful thanks to the National Cancer Institute, Bethesda, Maryland, USA, the source of the key information contained in this article.