Toasting a marshmallow over an open flame often results in a charred, black exterior. This common practice raises a question for health-conscious consumers: can that burnt sugar coating cause cancer? Marshmallows are primarily composed of sugar and gelatin, a blend of carbohydrates and protein. When these ingredients are exposed to high heat, they undergo chemical changes that produce potentially hazardous compounds.
How Burning Sugar Creates Acrylamide
The browning of a marshmallow results from the Maillard reaction, a chemical process where amino acids and sugars react under heat. This reaction creates the desirable flavor and color in many cooked foods. When temperatures exceed about 250°F (120°C), this reaction generates a specific chemical called acrylamide.
Acrylamide is a byproduct formed when the amino acid asparagine, found in the marshmallow’s gelatin, reacts with the sugars. The darker the exterior becomes, the higher the concentration of acrylamide, indicating an advanced stage of the chemical process. The International Agency for Research on Cancer (IARC) classifies acrylamide as a Group 2A agent, meaning it is a probable human carcinogen based on animal studies. While high doses have caused cancer in laboratory animals, human epidemiological evidence remains less conclusive.
Are Marshmallows Different Than Burnt Meat
While burnt marshmallows produce acrylamide, the chemical profile of charred meat is distinctly different and carries a higher theoretical risk. Burning muscle meat, such as beef or chicken, creates two other classes of mutagenic compounds: Heterocyclic Amines (HCAs) and Polycyclic Aromatic Hydrocarbons (PAHs). HCAs form when amino acids, creatine, and sugars in the muscle tissue react at high temperatures, particularly above 300°F.
PAHs form when fat and juices drip onto the heat source, creating smoke that deposits these compounds onto the meat’s surface. Unlike acrylamide, HCAs and PAHs are specifically linked to the high-heat preparation of muscle protein and fat. These compounds have demonstrated potent DNA-mutating properties in lab studies. The potential for high concentrations of these carcinogens in heavily charred meat differentiates its risk profile from that of a burnt marshmallow.
Understanding Risk Versus Occasional Exposure
The practical health risk of a burnt marshmallow relies on the concept of “dose makes the poison.” This means the total quantity of a substance consumed over time determines its effect. Acrylamide is already a ubiquitous part of the modern diet, found in common foods like coffee, potato chips, toast, and crackers.
For the average person, dietary exposure from these daily staples far outweighs the negligible amount ingested from an occasional burnt marshmallow. The U.S. Food and Drug Administration (FDA) advises consumers to focus on adopting a healthy, balanced eating plan overall. The risk associated with acrylamide is a concern for long-term, high-frequency consumption, not for isolated incidents. While science confirms that charring a marshmallow creates a probable carcinogen, the overall risk from enjoying an occasional snack remains extremely low.