Production, metabolism and inhibition of heterocyclic aromatic amines produced from meat cooking

soon Food Science and Human Health In this study, researchers review the carcinogenic and mutagenic properties of heterocyclic aromatic amines (HAAs), which are pollutants commonly found in various food products. Additionally, the authors discuss the natural mechanisms by which HAA production can be inhibited and the potential for flavonoids to reduce the toxicity of these compounds.

Studies: The role of flavonoids in reducing food-derived heterocyclic aromatic amines of human health concern. Image Credit: Sea Wave / Shutterstock.com

What are HAAs?

Despite the numerous health benefits associated with consuming meat as a result of their high nutrient content, overheating and/or improper cooking of these food products can lead to the formation of toxic substances, including nitrosamines, polycyclic aromatic hydrocarbons and HAAs.

For example, HAAs contain at least one heterocyclic ring as well as atoms of at least two different elements and at least one amine group. To date, more than 30 different types of carcinogenic and mutagenic HAAs have been isolated and identified in overcooked meat products.

In addition to meat products, varying concentrations and types of HAAs have been identified in other food products, including coffee and spirits such as whiskey, wine, beer, brandy, and Japanese sake.

How are HAAs metabolized in the human body?

Following consumption of food products contaminated with HAAs, these chemicals enter the circulation and are then absorbed and metabolized by the digestive tract. Recent studies suggest that the gut microbiota may have an important role in the conversion of HAA to genotoxic metabolites.

For example, gut bacteria activate HAAs, possibly by breaking down glucuronide-conjugated HAAs; however, more research is needed to confirm this hypothesis.

Conversely, the glucuronidase activity of the gut microbiome may also be involved in the conversion of HAAs. In addition to glucuronidase, various other intestinal enzymes such as sulfatase and nitro-reductase may also contribute to the genotoxic potential of HAAs.

Monitoring HAAs

Methylimidaquinoline (MeIQx) and phenylimidazo(4,5-b)pyridine (PhIP), both of which are abundant HAAs, are commonly measured in urine samples to monitor the circulation of these chemicals in patients.

Despite the ease of collecting urine for detection and monitoring of HAAs, several challenges are associated with this approach, including the selection of a single biomaterial and the limited types of HAAs detectable through such biological sample. Therefore, further work is needed to enable the identification of HAAs in other sample types for long-term monitoring.

Factors contributing to HAA formation

The process of heating meat, which contains the precursor molecules necessary to produce HAAs, is also the ideal environment for such reactions. In particular, several factors involved in the cooking process such as heating method, temperature and total time can change the type and amount of HAAs produced.

HAA concentrations appear to rise as prolonged high-temperature heating increases. Conversely, long heating times in the presence of a humid environment resulted in decreased HAA production.

Gentle heating approaches such as steaming, boiling, and microwave heating produce less HAA. Comparatively, stir-frying has been shown to produce more HAA.

In addition to heating time, varying levels of precursors found in meat products can also determine the amount of HAA in the final cooked product. For example, high sugar levels, which are important precursors for HAA formation, reduce HAA formation, especially when they exceed creatine levels. Certain sugars, such as those rich in both glucose and fructose, have also been shown to inhibit HAA production.

How do flavonoids inhibit HAA?

There are four types of flavonoids, which include flavonols, isoflavones, flavanols, and dihydroflavones. Certain flavonoids, including epigallocatechin gallate (EGCG), luteolin, and quercetin, have been shown to inhibit the synthesis of HAAs, including MeIQx, PhIP, and imidazoquinolinone (IQ).

The possible mechanism by which flavonoids inhibit HAA formation is a free radical reaction in which pyridine, pyrazine and other free radicals are destroyed by the antioxidant activity of these substances.

This theory was confirmed in a study that showed that naringenin, quercetin, and other flavonoids combine with phenylacetaldehyde to form specific compounds that bind to the activated carbonyl group, thereby inhibiting further reaction between phenylacetaldehyde and creatinine, thereby inhibiting the formation of PhIP. Similarly, both apigenin and lutolinin have been shown to exhibit antioxidant activities to reduce the formation of HAAs.

solution

Further research will determine how flavonoid active sites and key functional groups prevent the development of HAAs. Selecting different types of flavonoids and examining their effects on HAA formation in real-life settings such as a barbecue system can provide a theoretical basis for managing the formation of HAAs and reducing health risks.