What is Aflatoxin Toxicity?
Aflatoxins are harmful substances produced by certain types of mold, mainly Aspergillus flavus and Aspergillus parasiticus. These molds are found in soil, hay, decaying plants, and grains. Health issues caused by aflatoxins can occur after both short-term and long-term exposure. The name “aflatoxin” derives from Aspergillus flavus and was first used in the 1960s when such a toxin caused a disease in turkeys. Later, it was discovered to cause cancer in rainbow trout that consumed peanut and cottonseed meals.
Intake of aflatoxins through diet can have harmful and even produce cancer-causing effects in both humans and animals. Over the past 50 years, there have been numerous studies into the symptoms, markers, production, and ways to reduce the toxicity of this substance. These studies mainly concerned humans, farm animals, and laboratory animals, paving the way to discover how aflatoxin toxicity affects different species.
Aflatoxins are a subgroup of toxic substances called mycotoxins, produced by fungi. These toxins typically form during the growth, harvest, storage, and processing of food. The U.S. Food and Drug Administration (FDA) classifies aflatoxins as an unavoidable food contaminant. Symptoms of exposure to high levels of aflatoxins can include nausea, vomiting, stomach pain and fits. Long-term exposure can lead to severe health issues such as liver damage, weakened immunity, and birth defects. In developing countries, aflatoxins are one of the leading causes of liver cancer.
There are different types of aflatoxins, such as aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2), which are produced by both Aspergillus flavus and Aspergillus parasiticus. The most toxic among all aflatoxins is thought to be AFB1. Aflatoxin M1 (AFM1) — found in the fermentation broth of Aspergillus parasiticus — and aflatoxin M2 are created when a liver infected with the Aspergillus fungus breaks down AFB1 and AFB2. AFM1 can be transmitted through milk.
Scientific organizations like the International Agency for Research on Cancer (IARC) underline the health risks of aflatoxins by classifying AFB1 and AFM1 as group 1 and group 2B human carcinogens, respectively.
What Causes Aflatoxin Toxicity?
About a quarter of the world’s crops are affected by a type of toxin called mycotoxin, especially one called aflatoxin. This is commonly seen in crops like cassava, cottonseed, chili pepper, corn, wheat, millet, peanuts, rice, sesame, sunflower seeds, and various spices. These crops can become contaminated during their growth and development due to a fungal infection, or while being stored or transported, especially if they’re exposed to warm humid conditions or severe drought.
When animals eat food contaminated with aflatoxin, this toxic substance can end up in the eggs, dairy products, and meat produced from these animals,exposing humans to it.
Some types of fungus, including those from the Aspergillus, A. flavus, A. parasiticus, and A. minus species, are known to produce variants of aflatoxin. There’s also a type called Emericella fungus that has the ability to produce aflatoxin. There are four main types of aflatoxins, and they are named based on their colors under UV light (green or blue). Out of these types, AFB is the most harmful one. It’s very harmful to the liver, causes genetic mutations, and unfortunately, it’s also the most common type found around the world.
It’s important to know that humans and livestock can be exposed to aflatoxins through consumption of contaminated crops. This includes corn, cottonseed, peanuts, sorghum, figs, tree nuts, and spices. Other risk factors include stress on crops due to drought or insect damage, warm and humid conditions, temperatures around 30 C (or 86 F), and various other environmental factors such as substrate, CO levels, and time.
Risk Factors and Frequency for Aflatoxin Toxicity
Aflatoxin is an issue that affects around 4.5 billion people in developing countries, particularly children. This harmful substance can lead to serious health issues such as stunted growth, delayed development, liver damage and, in severe cases, liver cancer. Various studies have reported a link between growth issues in children and aflatoxin exposure, and ongoing research is attempting to determine a clear cause-and-effect relationship.
Adults, although more resistant to the effects of aflatoxin, are not immune. Aflatoxin exposure can lead to the development of hepatocellular carcinoma (a type of liver cancer), accounting for between 4.6% and 28.2% of all cases worldwide. Furthermore, high-dose acute exposures can be fatal in approximately 25% of instances.
- Around 4.5 billion people in developing countries are exposed to aflatoxin.
- Children are more adversely affected by exposure, leading to growth stunting and development delays.
- Exposure can cause liver damage and liver cancer.
- Research is ongoing to find a direct link between growth issues in children and aflatoxin exposure.
- Adults, although more tolerant, remain at risk.
- Aflatoxin exposure can contribute to 4.6% – 28.2% of liver cancer cases globally.
- High-dose exposures can be lethal, leading to death in about a quarter of the cases.
Signs and Symptoms of Aflatoxin Toxicity
Aflatoxin toxicity is a health issue related to your diet, surroundings, and professional activities. It’s influenced by various factors including your gender, age, overall health, immune system, environmental conditions, and diet. The symptoms can be non-specific, but changes related to liver function are most often noted. Adults can usually handle aflatoxins, while children may be at a higher risk, and may face severe malnutrition due to aflatoxin toxicity.
There are two types of ailments related to aflatoxin poisoning: acute and chronic. Acute toxicity happens when you consume a large amount of aflatoxins in a short period, while chronic toxicity results from eating small amounts of aflatoxins over a long period.
The main symptoms of acute aflatoxin toxicity include:
- Nausea
- Yellowing of the skin and eyes (jaundice)
- Itching
- Vomiting
- Bleeding
- Stomach pain
- Tiredness
- Swelling
- Seizures
- Coma
- Death
The chronic toxicity from aflatoxins can lead to:
- Slowed growth and development in children
- Weakening of the immune system
- Liver cancer with symptoms like weight loss, stomach mass, lack of appetite, vomiting, nausea, bleeding, and mental issues
Moms-to-be should note that exposure to aflatoxin has been linked to preterm birth and late-term miscarriage.
Testing for Aflatoxin Toxicity
If your doctor thinks you may have been poisoned by something called an aflatoxin, they have a few ways to check. One way is to test the levels of aflatoxin in any food you’ve eaten, or to look for signs of it in your body.
There are a few different methods that can be used to spot aflatoxin in food or animal feed. These include:
- Thin-layer chromatography (TLC)
- High-performance liquid chromatography (HPLC)
- Liquid chromatography-mass spectroscopy (LCMS)
- Enzyme-linked immune-sorbent assay (ELISA)
The ELISA method is used to detect a certain compound in your blood that shows there’s aflatoxin in your body.
In addition, other techniques are used to measure the level of aflatoxin in your body. One method involves testing your urine. This method measures aflatoxin exposure in the last 24 hours. Because people’s diets can vary, this method may not be ideal for measuring long-term exposure. Another method involves testing the level of a specific compound in your blood, and can detect aflatoxin exposure over a longer period.
Your doctor might also need to examine how well your liver is working. This is done using tests like prothrombin time, the international normalized ratio, activated partial thromboplastin time, and the measurement of substances like albumin, bilirubin, aspartate transaminase, and alanine transaminase in your body. In some cases, they might decide to use medical imaging like ultrasound or a CT scan to get a closer look at your liver.
Depending on your symptoms, your doctor may also order other tests like a basic metabolic panel, complete blood count, or tests to check how your kidneys are doing.
Treatment Options for Aflatoxin Toxicity
Acute aflatoxicosis, a form of poisoning, doesn’t have a specific cure. The best course of action is to remove the food source causing the issue and replace it with food that isn’t contaminated, which may prevent further harm. Treating the condition mostly involves alleviating the symptoms and giving supportive care. Optimizing the dietary needs with supplements may help in the recovery process. The main goal is to manage the symptoms effectively.
Immediate symptoms such as a high temperature, feeling nauseous, vomiting, and having fits (convulsions) need proper attention. If the indications point towards acute liver failure, it should be identified quickly and the patient should then receive care in an intensive care environment.
If liver cancer (hepatocellular carcinoma) occurs, there are several treatment options available, which include:
- Surgery to remove part or all of the liver (surgical resection)
- A combination of surgery and ablation (a procedure that destroys cancer cells)
- Replacing the diseased liver with a healthy one from a donor (orthotopic liver transplantation)
- Thermal ablation (using heat to destroy cancer cells)
- Injecting alcohol into the tumor (percutaneous alcohol injection)
- Blocking the blood supply to the tumor (transarterial embolization)
- Chemoembolization (a combination of chemotherapy and embolization)
- Use of high-energy rays to kill cancer cells (radiotherapy)
- A combination of systemic chemotherapy and radioembolization
What else can Aflatoxin Toxicity be?
Aflatoxin toxicity is noted for its harmful impact on the liver. As a result, the symptoms can be similar to those observed in other types of liver damage.
Here are some other medical conditions that may seem like aflatoxin toxicity at first glance:
- Drug poisoning (due to substances like acetaminophen, tetracycline, halothane, isoniazid, and ecstasy)
- Poisoning from Amanita mushrooms
- Infections, such as hepatitis-A/B/C/D/E, cytomegalovirus, and Epstein Barr virus
- Autoimmune hepatitis, a disease where the immune system attacks the liver
- Metabolic diseases like alpha-1 antitrypsin deficiency and Wilson disease
- Veno-occlusive diseases, which involve the blocking or narrowing of liver veins
These conditions might present similar symptoms, so it’s crucial for the doctor to consider them to make the right diagnosis.
What to expect with Aflatoxin Toxicity
The severity and long-term effects of aflatoxin poisoning rely on factors like the dose and length of exposure, a person’s nutrition levels, immune system strength, and overall health. Short-term exposure may lead to symptoms like nausea, vomiting, and abdominal pain, which typically only require treatment to relieve these symptoms. However, children who are exposed to large amounts of aflatoxin could die from this acute poisoning.
Long-term exposure to small amounts of aflatoxin can cause irreversible liver damage, leading to conditions like cirrhosis and a type of liver cancer known as hepatocellular carcinoma. These health issues are serious and often result in significant illness and death.
Possible Complications When Diagnosed with Aflatoxin Toxicity
Aflatoxin is a harmful substance that can cause serious health problems if one is exposed to it in large amounts or over a long period of time. If a person ingests a large dose of aflatoxin, it could lead to severe liver damage and a breakdown of muscle tissue. Long term, constant exposure to aflatoxin may cause scarring of the liver (cirrhosis) and may end up causing liver cancer. It’s also linked to gall bladder cancer.
In kids, being exposed to aflatoxin can affect their growth and development. It could stunt their growth, cause nutritional deficiencies, and hinder their developmental progress.
Preventing Aflatoxin Toxicity
Aflatoxin is a harmful substance that can affect agriculture, animals, and human health. Spreading awareness about aflatoxin and its harmful effects can significantly ensure safer food and reduce health problems related to aflatoxin. Aflatoxins are commonly found in various food sources such as grains, oilseeds, spices, nuts, and animal products. That’s why it’s crucial to be careful with food choices. Also, farmers need to watch for possible aflatoxin contamination at all stages – from growing crops to storing and transporting them.
People should be made aware of the early signs of exposure to aflatoxins and be encouraged to seek medical help if they suspect they have been exposed. Research has indicated that a diet rich in vegetables from the apiaceous family, like celery, carrots, parsley, and parsnips, can help lessen the cancer-causing effects of aflatoxins.
