Carcinogens from Cooking (Pt. 2)

It is well known that cooked meats can contain carcinogens (See Carcinogens from Food, Part 1 for the full story), but did you know that carcinogens can also be found in starchy foods? During high temperature cooking such as frying, roasting, and baking, sugar and starch containing foods become beautiful and browned thanks to a process called the Maillard reaction. However, a byproduct called acrylamide is formed during reactions between naturally occurring sugars (glucose and fructose) and amino acids (asparagine). Acrylamide is a potential carcinogen which can found in some of our favourite plant-based foods. The compound is found in the greatest amounts in cooked potato products such as potato chips and French fries. Other notable sources of acrylamide include grain containing products such as baked goods and cereal, peanuts, legumes, asparagus, coffee, cigarette smoke, and environmental exposure. Similar to carcinogen formation in meats, acrylamide formation is influenced by cooking temperature and time. The higher the temperature used and longer the cooking time, the more acrylamide is formed. Acrylamide formation varies greatly, as it is also influenced by moisture, sugar, and amino acid content of the raw foods used. For example, whole-grain products contain higher amounts of the amino acid asparagine, and thus, whole-grain products may contain higher amounts of acrylamide compared to their more refined counterparts. However, don’t go ahead and switch to white bread just yet. New technologies are being developed in attempts to lower dietary acrylamide intake. Pre-treatment of raw foods using an enzyme called asparaginase has showed promise in reducing acrylamide in some baked products. Longer yeast fermentations in product development has also shown promise in reducing acrylamide formation, although total content of acrylamide is relative to the strain of bacteria used in the fermentation process. In most cases, the acrylamide content can be reduced, but not removed completely. However, reducing acrylamide content in foods while maintaining their sensory properties remains an issue. It should be noted that the link between acrylamide and human cancer is still under ongoing research. No direct link can be concluded due to inconsistent study results and lack of human studies (most evidence based on animal studies). In general, most studies show no clear association between acrylamide exposure and cancer. However, current available information suggests that we should minimize the amount of acrylamide in our diet. The following are some methods of reducing dietary acrylamide intake:

  • Quit smoking – smokers have been observed to inhale 5 times more acrylamide from tobacco use than what is ingested from their their diet

  • Avoid cooking methods that use high temperatures like grilling, barbecuing, pan-frying, broiling, and roasting

  • Use lower temperatures when cooking starch containing products (less than120 degrees C)

  • Avoid over-cooking and burning foods – the less brown the better (ie. a light brown piece of toast / golden yellow fries are better than a blackened piece of toast / brown fries)

  • Get that side salad instead of fries the next time you order something out

  • Snack on something else instead of potato chips! ... Also choose snacks that are “baked” instead of fried

  • When preparing potatoes, soaking them beforehand, and boiling instead of frying or baking with “dry heat” helps to reduce acrylamide formation

  • Cook potatoes stored at room temperature rather than from refrigerated temperature

  • Just eat an overall healthy diet – it has many benefits beyond reducing cancer risk!

The following table is a comparison of Disability-Adjusted Life Years, or overall disease burden risk of cancer from different food groups.

References Mucci, L., & Adami, H. (2009). The plight of the potato: is dietary acrylamide a risk factor for human cancer?. JNCI: Journal Of The National Cancer Institute, 101(9), 618-621. doi:jnci/djp080 Pedreschi, F., Granby, K., & Mariotti, M. S. (2014). Current issues in dietary acrylamide: formation, mitigation and risk assessment [electronic resource]. Journal Of The Science Of Food And Agriculture, 94(1), 9-20. Riboldi, B. P., Vinhas, Á. M., & Moreira, J. D. (2014). Risks of dietary acrylamide exposure: A systematic review. Food Chemistry, 157310-322. doi:10.1016/j.foodchem.2014.02.046 Virk-Baker, M. K., Nagy, T. R., Barnes, S., & Groopman, J. (2014). Dietary Acrylamide and Human Cancer: A Systematic Review of Literature. Nutrition & Cancer, 66(5), 774-790. doi:10.1080/01635581.2014.916323 Acrylamide and Cancer Risk. American Cancer Society. Retrieved from Dastmalchi, F., Razavi, S. H., Faraji, M., & Labbafi, M. (2016). Effect of Lactobacillus casei- casei and Lactobacillus reuteri on acrylamide formation in flat bread and Bread roll.Journal Of Food Science And Technology, 53(3), 1531-1539. doi:10.1007/s13197-015-2118-3 Forstova, V., Belkova, B., Riddellova, K., Vaclavik, L., Prihoda, J., & Hajslova, J. (2014). Acrylamide formation in traditional Czech leavened wheat-rye breads and wheat rolls.Food Control, 38221-226. doi:10.1016/j.foodcont.2013.10.022 Fredriksson, H., Aman, P., Rosen, J., & Tallving, J. (2004). Fermentation reduces free asparagine in dough and acrylamide content in bread. Cereal Chemistry, 81(5), 650-653.

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