Each year this time I am confronted with the same hesitant question from friends and clients alike: Grilling is an integral part of my summer, more than just the task of preparing food, a social event, but I am scared I might be fueling cancer cells!
Let’s start by distinguishing between the type of food grilled, the method used (there is more to “just grilling”) and and the actual end result. There is a difference, and you may be glad to hear that you can indeed enjoy a few guiltless grill fests this summer!
For those of you enjoying some occasional grilled meat, you need to understand that when meat is being browned, it produces certain molecules called cyclic amines. These are responsible for the taste we associate with cooked meat, and it is also a signal to tell us that the meat is now safe to eat.
About a decade ago it was discovered that cooking meat, both red and white such as chicken, at high temperatures for an extended period of time produces additional molecules that can be carcinogenic if eaten on a frequent basis. These are the so-called Heterocyclic Amines (HCAs), and there are over 17 different ones now identified.
According to the National Cancer Institute, HCAs are formed when creatine, an organic acid found in muscle fiber combines with the amino acids in protein and sugar molecules during high temperature exposure. In addition, when fat and juices from meat grilled over an open heat source drips onto that source, such as a fire, another potentially carcinogenic group of compounds are formed, called Polycyclic Aromatic Hydrocarbons (PAHs). These can coat the meat, and are a typical component of charred, blackened and even smoked food. Incidentally, PAHs are also found in cigarette smoke and car exhaust fumes.
Both HCAs and PAHs can potentially damage genes, but need to be “activated” first by certain enzymes. The amount and activity of such enzymes of course differs from person to person and is thus difficult to measure. Studies involving humans have been inconclusive as to whether or not this may lead to cancerous genetic mutations. Often researchers have to rely on information gleaned only from personal questionnaires about personal eating habits.
What studies have shown is that the amount of HCAs in cooked meat is directly related to the intensity of heat, length of exposure to high heat and also type of meat. The higher the heat and the longer the contact time with high heat significantly increases the amount of HCAs present. Chicken with skin seems to harbor higher levels of HCAs under the above conditions than for example beef. Bacon seems to be top of the list.
So besides being mindful of the temperature, contact time and type of meat, what else can you do to potentially lower these carcinogenic compounds in your beloved summer grill feast? In an article published in the Natural Medicine Journal (July 2010, Vol 2, Issue 7), Dr Jacob Schor, ND, FABNO, lists the following ingredients as proven HCAs reducers when mixed into marinades or rubs applied to meat prior to grilling:
- Virgin Olive Oil
- Garlic, onions & lemon juice (ideal 1 part lemon juice to 2 parts garlic & onions)
- Beer and wine
- Herbs, in particular rosemary
- Fruits, in particular cherries and extracts of blue- and blackberries, kiwi and watermelon
- Extracts of green tea and rooibos tea
- Extracts of parsley and spinach
An interesting fact: traditional BBQ sauce was shown to actually double and even triple HCAs, researchers liken it to the fact that excess fructose present in tomato solids as well as an added ingredient in many commercial sauces may be the underlying cause.
When grilling veggies of course, there is no danger of any HCAs or even PAHs forming as there is no creatine present as in meats, nor are there fat juices dripping down causing potential flare ups. So grill those away at your hearts content! But beware of charring or blackening your veggies as this may cause another possible carcinogen, benzoapyrene, to form.
On another note: Avoid using aluminum foil as a base or to wrap your food in while grilling as it has been shown to leach aluminum into food at levels much higher than the permissible limit set by the World Health Organisation. In particular when the foil is in contact with acidic food such as marinated meats or veggies.
Here are 10 quick guiltless grilling tips:
1. have something in between your meat and the open flame such as a flat cast iron platter
2. flip often, whether it’s skinless chicken thighs, salmon filets or red pepper slices, not allowing any charring
3. remove skin from chicken and fish, they carry higher HCAs levels
4. cut off any charred spots
5. trim excess fats to prevent flare-ups from drippings
6. use indirect heat, have the heat source directly underneath your meat turned off
7. marinade at least 6 hours ahead – this length of time allows the flavors to fully infuse
8. do not use marinade used for raw meats over your grilled meats to avoid bacterial infections
9. avoid well done, go for medium-rare in red meats, including burgers
10. clean your grill! Scrape off any charred residue at all times
Here’s my favorite now not-so-secret-anymore home-made marinade recipe, hope you enjoy it as much as my family and friends do!
For 2 packets of organic skinless chicken thighs (2 pounds), london broil or pork loin
- ¼ cup virgin olive oil
- juice of 1 large or 2 small lemons
- ¼ cup tamari sauce (wheat-free soy sauce)
- 10-15 swirls with black pepper mill
- ½ teaspoon cayenne pepper
- 1 tablespoon ground paprika
- 1 teaspoon turmeric
- ½ teaspoon all spice
- 3 tablespoons dried herbs (choose: rosemary, thyme, oregano, majoram…)
- 2-4 garlic cloves, minced
- Choose: ½ cup of beer OR ½ cup red wine OR ½ cup blueberry / parsley puree (1 cup frozen blueberries, ½ cup fresh parsley, puree in blender)
- Optional: add ½-1 teaspoon sea salt or to taste
Combine all ingredients in bowl, whisk until emulsified, about 2-4 minutes. Place meat in flat casserole dish and pour over marinade, making sure the meat is fully submerged. Place in fridge overnight or at least 6 hours to infuse flavors.
Stephanie C. Melkonian PhD, Carrie R. Daniel PhD, MPH, Yuanqing Ye PhD, Nizar M. Tannir MD, FACP, Jose A. Karam MD, Surena F. Matin MD, Christopher G. Wood MD and Xifeng Wu MD, PhD, “Gene-environment interaction of genome-wide association study-identified susceptibility loci and meat-cooking mutagens in the etiology of renal cell carcinoma”, Cancer Volume 122, Issue 1, pages 108–115, January 1, 2016
Cross AJ, Ferrucci LM, Risch A, Graubard BI, Ward MH, Park Y, Hollenbeck AR, Schatzkin A, Sinha R, “A large prospective study of meat consumption and colorectal cancer risk: an investigation of potential mechanisms underlying this association”, Cancer Res. 2010 Mar 15;70(6):2406-14.
Stolzenberg-Solomon RZ, Cross AJ, Silverman DT, Schairer C, Thompson FE, Kipnis V, Subar AF, Hollenbeck A, Schatzkin A, Sinha R, “Meat and meat-mutagen intake and pancreatic cancer risk in the NIH-AARP cohort”, Cancer Epidemiol Biomarkers Prev. 2007 Dec;16(12):2664-75
Sinha R, Park Y, Graubard BI, Leitzmann MF, Hollenbeck A, Schatzkin A, Cross AJ, “Meat and meat- related compounds and risk of prostate cancer in a large prospective cohort study in the United States”, Am J Epidemiol. 2009 Nov 1;170(9):1165-77
Wu K, Sinha R, Holmes M, et al. Meat mutagens and breast cancer in postmenopausal women—A cohort analysis. Cancer Epidemiology, Biomarkers and Prevention 2010; 19(5):1301–1310.
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.
Kabat GC, Cross AJ, Park Y, et al. Meat intake and meat preparation in relation to risk of postmenopausal breast cancer in the NIH-AARP diet and health study. International Journal of Cancer 2009; 124(10):2430–2435.
Nerurkar PV, Le Marchand L, Cooney RV. Effects of marinating with Asian marinades or western barbecue sauce on PhIP and MeIQx formation in barbecued beef. Nutr Cancer. 1999;34(2):147-152.
Edenharder R, Sager JW, Glatt H, Muckel E, Platt KL. Protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino- 1-methyl- 6-phenylimidazo[4,5-b]pyridine (PhIP) in metabolically competent V79 cells.Mutat Res. 2002;521(1-2):57-72.
Nozawa H, Tazumi K, Sato K, et al. Inhibitory effects of beer on heterocyclic amine-induced mutagenesis and PhIP-induced aberrant crypt foci in rat colon. Mutat Res. 2004;559(1-2):177- 187.
Ghada Bassioni, Fathia S. Mohammed, Essam Al Zubaidy and Issam Kobrsi, “Risk Assessment of Using Aluminum Foil in Food Preparation”, Int. J. Electrochem. Sci., 7 (2012) 4498 – 4509