Aflatoxins are highly toxic and carcinogenic compounds produced by molds like Aspergillus flavus and Aspergillus parasiticus, typically found in foods such as peanuts, corn, and tree nuts.
These mycotoxins, particularly aflatoxin B1, are among the most potent natural carcinogens, capable of causing liver cancer, immune suppression, and stunted growth in children.
Aflatoxins persist in food and animal feed even after processing, posing ongoing health risks. Chronic exposure leads to bioaccumulation in the liver, increasing the potential for severe health outcomes.
Detecting and managing aflatoxin contamination is crucial for ensuring food safety and public health.
Aflatoxins are a group of highly toxic and carcinogenic compounds produced as secondary metabolites by certain molds, primarily Aspergillus flavus and Aspergillus parasiticus. [7., 17.]
They are one type of mycotoxin, which are a larger group of toxic chemical compounds produced by molds.
These mycotoxins are formed when the molds colonize foods like peanuts, corn, cottonseed, tree nuts, and spices under favorable temperature and humidity conditions. [7., 16.]
The main aflatoxins are B1, B2, G1, and G2, with aflatoxin B1 (AFB1) being the most potent and carcinogenic. [3.]
Their production occurs when the mold's growth is stressed, such as during drought conditions or improper crop storage.
Aflatoxins are among the most carcinogenic substances known - they can cause acute toxicity leading to liver failure, hemorrhaging, and even death in severe cases. [7.] Chronic exposure increases the risk of developing liver cancer, as aflatoxins can bind to DNA and cause mutations, particularly in the p53 tumor suppressor gene. [7., 9.]
They can also suppress the immune system, and can cause stunted growth in children. [8., 12., 13.]
Worryingly, aflatoxins are highly stable and can persist in foods and animal feeds even after processing and cooking. They bioaccumulate in the body over time, especially in the liver, due to their lipophilic nature and resistance to metabolic breakdown. [1., 10., 11.]
Aflatoxin B1 is metabolized to the reactive aflatoxin-8,9-epoxide, which binds to DNA and proteins, initiating carcinogenesis. [13.]
Animals fed contaminated feed can pass aflatoxin metabolites into meat, milk, and eggs, posing risks to humans consuming these products.
Anti-aflatoxin biomarkers are a group of compounds or metabolites that can be measured in biological samples to assess exposure to aflatoxins, which are toxic and carcinogenic metabolites produced by certain molds.
These biomarkers provide a direct measure of internal exposure and can help evaluate the associated health risks.
A variety of biomarkers have been used to identify the presence of aflatoxins in humans and animals.
One of the most widely used anti-aflatoxin biomarkers is the aflatoxin-albumin adduct (AF-alb). AF-alb is formed by the metabolic activation of aflatoxin B1 (AFB1) and its subsequent binding to albumin in the blood.
It serves as a reliable biomarker of integrated AFB1 exposure over the previous 2-3 months.
AF-alb is measured using immunoassays like ELISA or LC-MS/MS methods.
AFM1 is a hydroxylated metabolite of AFB1 that is excreted in urine. Its measurement reflects recent AFB1 exposure over the past 24-48 hours.
AFM1 levels in urine are analyzed by immunoassays or LC-MS/MS.
AF-N7-Gua is a product of AFB1 binding to DNA, forming adducts. Its measurement in urine indicates the biologically effective dose of AFB1 that has led to DNA damage.
AF-N7-Gua is typically analyzed using LC-MS/MS methods.
Testing for aflatoxins, particularly aflatoxin B1, B2, G1, and G2, has significant clinical utility in assessing exposure and potential health risks.
Aflatoxin B1 is one of the most potent naturally occurring carcinogens and is strongly linked to the development of hepatocellular carcinoma (liver cancer), especially in individuals with chronic hepatitis B or C infections. [2.]
Measuring aflatoxin levels in food, feed, and biological samples like blood or urine can help identify exposure sources and quantify the extent of exposure.
This information is crucial for risk assessment, implementing preventive measures, and monitoring the effectiveness of interventions aimed at reducing aflatoxin contamination.
Additionally, aflatoxin testing plays a vital role in food safety and regulatory compliance, as many countries have established maximum permissible limits for these toxins in various food products to protect public health. Accurate and sensitive analytical methods for aflatoxin detection are essential for enforcing these regulations and ensuring the safety of the food supply chain.
These are minor metabolites of AFB1 that can be measured in urine as additional biomarkers of recent exposure.
Various biological samples can be employed to detect and quantify anti-aflatoxin biomarkers, particularly blood, urine and nasal secretions.
Blood samples are typically collected via venipuncture in a clinical setting, while urine and nasal secretion samples may be collected from the comfort of home.
It is important to consult with the ordering provider prior to sample collection, as certain protocols may be recommended beforehand.
Because of the high level of toxicity of aflatoxins, optimal test results indicate undetectable levels of aflatoxins.
Elevated levels of aflatoxins indicate recent or current exposure to aflatoxins. However, because they are known to bioaccumulate, testing positive for the presence of aflatoxins may indicate a persistent historical exposure. [4., 5., 15.]
Low or undetectable levels of aflatoxins are considered ideal.
In addition to the direct measurement of anti-aflatoxin biomarkers, other biomarkers can provide complementary information about aflatoxin exposure and its potential health effects.
Aflatoxin exposure is known to induce oxidative stress, which can lead to cellular damage and contribute to the development of various diseases.
Biomarkers such as malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) can be measured to assess oxidative stress levels and the associated risk of aflatoxin-related toxicity. [14.]
Since the liver is a primary target organ for aflatoxin toxicity, monitoring liver function biomarkers like alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin can provide insights into the extent of hepatic injury and potential liver damage caused by aflatoxin exposure.
Aflatoxin exposure can trigger inflammatory responses, and biomarkers such as C-reactive protein (CRP), interleukins (e.g., IL-6, IL-8), and tumor necrosis factor-alpha (TNF-α) can be measured to evaluate the inflammatory status and associated health risks.
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