Heterocyclic Amines

Sporadic colorectal cancer can arise as a result of exposure to carcinogens. Compared to genetic or hereditary colorectal cancers, about 75% of all colorectal cancers occur sporadically. In such cases, cancerous growth does not occur because of preexisting mutations that are present in the cells from birth. Rather, these mutations occur as a result of external factors that cause damage to DNA.

Exposure to carcinogens may happen as part of occupational hazards, but more commonly occurs because of diet and lifestyle. In fact, diet contributes to about 80% of colorectal cancer cases. Heterocyclic amines (HCAs), or sometimes called heterocyclic aromatic amines, are carcinogens that are produced through certain food preparation methods. This article takes a closer look at how HCAs are produced and how they exert their carcinogenic properties.

Heterocyclic amines are organic compounds that contain a heterocyclic ring and at least one amine group.

HCAs are toxic compounds that are produced through certain food preparation methods. Particularly for foods rich in protein such as meat, cooking them at high heat produces several carcinogens, including HCAs. Specifically, cooking meats at high temperatures can induce the Maillard reaction, or in simpler terms, cause meat to brown. This process is not restricted to meat, however, and affects all food types that are high in amino acids.

Aside from meat products, HCAs may also be found in coffee, alcoholic beverages, as well as in the environment.

Similar to nitrosamines, HCAs in their “normal” state do not react with DNA, and instead only exert carcinogenic effects when they are metabolized by cytochrome P450 enzymes and other enzymes. The resultant nitrenium ions produced from the breakdown of HCAs are able to react with the guanine nucleotide bases in DNA. This creates damaging DNA adducts that subsequently leads to abnormal DNA replication.

Given that HCAs occur as a result of cooking proteinaceous food at high temperatures, the solution is to change the way the food is prepared. Employing cooking methods that use lower temperatures such as sous vide can minimize the production of HCAs and thus reduce the risk of colorectal cancer.