We’ve all been there – a slice of toast left a little too long, chips with a blackened edge. But should you avoid eating burnt food? For years, scraping off the charred bits was just a habit. Now, research suggests it might be more important than we thought.
In 2002, a study from the University of Stockholm revealed that heating certain foods, like potatoes, bread, biscuits, cereal, and coffee, above 120°C (248°F) leads to the formation of a chemical called acrylamide. This occurs when the sugar content in these foods reacts with the amino acid asparagine, a process known as the Maillard reaction. While this reaction gives food its desirable browned color and flavor, it also introduces a potentially harmful compound.
The Acrylamide Connection: Is It a Cancer Risk?
Acrylamide has been classified as a carcinogen in animal studies, although at doses significantly higher than those typically found in human food. The European Food Safety Authority suggests that acrylamide could also increase the risk of cancer in humans, particularly in children. However, research on humans is still ongoing, and definitive conclusions have yet to be reached.
Fatima Saleh, an associate professor of medical laboratory sciences at Beirut Arab University in Lebanon, notes, “After almost 30 years of its classification as a ‘probable human carcinogen’, there is still inconsistent evidence of its definite carcinogenicity in humans. However, if we continue to do further studies on humans, we might have adequate data to change acrylamide’s classification to a human carcinogen.”
Neurological Effects and Long-Term Exposure
Beyond cancer concerns, scientists are certain that acrylamide is neurotoxic to humans, meaning it can negatively affect the nervous system. The exact mechanisms aren’t fully understood, but theories suggest acrylamide attacks structural proteins within nerve cells or inhibits anti-inflammatory systems that protect these cells from damage.
The toxic effects of acrylamide are cumulative. This means that consuming even small amounts over a long period could increase the risk of organ damage in the long term. Animal studies suggest that long-term exposure to dietary acrylamide might also increase the risk of neurodegenerative diseases like dementia and could be linked to neurodevelopmental disorders in children.
Federica Laguzzi, assistant professor at the Institute of Environmental Medicine at Karolinska Institutet in Sweden, explains, “Acrylamide passes through all tissue, including the placenta, because it has a low molecular weight and is soluble in water.” Her research has linked higher acrylamide intake in pregnant individuals to lower birth weight, head circumference, and length in newborns.
Hormonal Pathways and Cancer Risk
Leo Schouten, an associate professor of epidemiology at Maastricht University in the Netherlands, proposes that the mechanism behind acrylamide’s potential cancer-causing effect could be related to hormones. His research team investigated the link between acrylamide intake and cancer in non-smokers and found a higher risk of endometrial and ovarian cancers in women with high acrylamide exposure. They also found a slight link between acrylamide intake and kidney cancer in further studies.
Schouten suggests that acrylamide may affect estrogen or progesterone levels, which could explain the increased risk of female genital cancers. While laboratory studies on rats have also shown links between acrylamide intake and cancer in mammary glands, thyroid gland, testes, and the uterus, these findings don’t automatically translate to similar risks in humans.
Challenges in Measuring Acrylamide Intake
One of the biggest challenges in understanding the risks of acrylamide is accurately measuring how much we consume. Most epidemiological studies rely on dietary questionnaires, which can be subject to reporting biases. While some researchers have attempted to measure acrylamide intake through biomarkers in urine and blood, these methods haven’t yielded conclusive results.
Protective Measures and Industry Efforts
Despite the uncertainties, there are potential protective measures that could limit the risks associated with consuming burnt food. These could include inherent reparative mechanisms in humans or the presence of antioxidants in food that counteract the toxic effects of acrylamide.
The food industry is also taking steps to reduce acrylamide levels in our food. The EU is setting maximum allowable levels for acrylamide, and producers are exploring ways to minimize its formation during food processing. For instance, researchers are working to reduce asparagine levels in wheat, the precursor to acrylamide, through genetic modification.
Reducing Acrylamide at Home
You can also take steps to reduce acrylamide formation when cooking at home. For example, when making fries, soaking the cut potatoes in hot water for 10 minutes can reduce acrylamide formation by almost 90%.
Saleh advises home cooks to take simple precautions:
- Soak potatoes: Prior to frying or roasting potatoes, soak them in water for at least 15-30 minutes. This helps reduce the asparagine content on the surface.
- Avoid overcooking: Try not to overcook foods, especially starchy items like potatoes and bread. Aim for a golden yellow color rather than a dark brown or burnt appearance.
- Cook at lower temperatures: When possible, cook foods at lower temperatures to reduce the formation of acrylamide.
- Store potatoes properly: Store potatoes in a dark, cool place, but not in the refrigerator. Refrigeration can increase acrylamide formation during cooking.
The Future of Acrylamide Research
The scientific interest in acrylamide health risks has grown again in recent years. As research continues and more accurate measurement methods are developed, the link between acrylamide intake and cancer risk will hopefully become clearer.
Conclusion: Should You Avoid Burnt Food?
While the evidence is still evolving, the existing research suggests it’s wise to be cautious about eating burnt food. Scraping off the burnt bits is a simple precaution that could potentially reduce your exposure to acrylamide. More research is needed to definitively determine the risks to humans, but in the meantime, moderation and mindful cooking practices are recommended.
References
- University of Stockholm study: https://pubmed.ncbi.nlm.nih.gov/14530144/#:~:text=On%20April%2024%2C%202002%20the,such%20as%20potatoes%20and%20bread.
- The Maillard Reaction: https://www.scienceofcooking.com/maillard_reaction.htm
- FDA on Acrylamide: https://www.fda.gov/food/process-contaminants-food/acrylamide#:~:text=Acrylamide%20has%20been%20shown%20to,and%20Agriculture%20Organization%2FWorld%20Health
- European Food Safety Authority on Acrylamide: https://www.efsa.europa.eu/en/topics/topic/acrylamide
- Research on Acrylamide Effects on Humans: https://pubmed.ncbi.nlm.nih.gov/25403648/
- Acrylamide and Neurotoxicity: https://www.frontiersin.org/articles/10.3389/fnut.2022.859189/full
- Acrylamide and Neurodegenerative Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5527102/
- Acrylamide Intake and Pregnancy Outcomes: https://www.sciencedirect.com/science/article/pii/S0013935122010325
- Acrylamide Intake and Deaths from Cancer: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9858116/
- Laguzzi’s research on acrylamide and cancer risk: https://www.frontiersin.org/articles/10.3389/fnut.2022.875607/full
- WHO on Acrylamide in food: https://www.who.int/news/item/27-06-2002-additional-research-on-acrylamide-in-food-essential-scientists-declare
- Nigel Halford’s research: https://www.rsb.org.uk/meet-our-members/my-lab-unlocked-professor-nigel-halford-frsb
