Acrylamide

Acrylamide is a chemical compound that forms naturally in certain foods during high-temperature cooking processes such as frying, roasting, and baking. It is produced when the amino acid asparagine reacts with naturally occurring sugars like glucose or fructose, primarily through a chemical process known as the Maillard reaction, which also gives cooked foods their characteristic color, flavor, and aroma. This reaction occurs only at sufficiently high temperatures, typically above 120°C (248°F), and the amount of acrylamide formed depends on the food type, cooking method, time, and temperature

• Nervous System Effects:

• • Acrylamide is neurotoxic. Workers exposed to high levels have reported muscle weakness, numbness in hands and feet, sweating, unsteadiness, and clumsiness. These symptoms are due to peripheral nerve damage135.
  • Chronic exposure can cause confusion, disorientation, fatigue, tremors, and poor coordination5.
• Reproductive Effects:

• • Animal studies show acrylamide reduces fertility in males by affecting sperm production. Similar effects are possible in humans at very high exposures, but not likely at dietary levels16.
• Cancer Risk:

• • Acrylamide is classified as a probable human carcinogen by the IARC and other agencies, based on evidence from animal studies. It has caused several types of cancer in animals, but human evidence is limited and not conclusive146.
  • There is some evidence linking acrylamide to pancreatic cancer in humans, but more research is needed56.
• Other Effects:

• • Skin and eye irritation can occur with direct contact5.
  • High exposure can also cause confusion, disorientation, and fatigue5.

Metabolism of Acrylamide

• Absorption and Distribution:

• • Acrylamide is rapidly absorbed from the gastrointestinal tract, lungs, and through the skin due to its low molecular weight6.
  • It is widely distributed in the body.
• Metabolism:

• • In humans, acrylamide is mainly metabolized via two pathways:

• • • Epoxidation: Conversion to glycidamide (a reactive epoxide) by cytochrome P450 enzymes. Glycidamide is more reactive and considered more toxic than acrylamide itself.
    • Conjugation: Direct conjugation with glutathione, leading to excretion.
• Excretion:

• • The main route of excretion is via urine, as both acrylamide and its metabolites (including glycidamide and glutathione conjugates)6.
  • Excretion is relatively rapid, but repeated exposure can lead to accumulation in some tissues6.

Binding and Molecular Targets Within the Body

• Binding to DNA, RNA, and Proteins:

• • Acrylamide and its metabolite glycidamide can bind to DNA, RNA, and proteins in various tissues and cells. These adducts (chemical modifications) can disrupt normal cellular function and increase the risk of mutations, which is a key mechanism for its carcinogenic potential6.
  • The binding to DNA (especially by glycidamide) is particularly concerning, as it can lead to genetic mutations and cancer6.
• Nerve Tissue Damage:

• • Acrylamide causes damage to nerve fibers, leading to the observed neurological symptoms35.

Acrylamide is considered toxic, with its main targets being the nervous system and reproductive system. In humans, high occupational exposure can lead to symptoms such as muscle weakness, numbness in the hands and feet, sweating, unsteadiness, and clumsiness

Summary Table

Main Foods That Create Acrylamide

Acrylamide is most commonly found in plant-based foods cooked at high temperatures. The main dietary sources include:

• Potato products: French fries and potato chips are among the highest sources

• Grain products: Crackers, bread, cookies, breakfast cereals, and crispbreads

• Coffee: Both roasted coffee beans and brewed coffee contain acrylamide

• Other sources: Canned black olives, prune juice, and some other processed foods may also contain acrylamide, but at lower levels

Is There a Safe Level?

Regulatory agencies have established safety benchmarks to guide exposure limits:

• European Union: The EU has set a benchmark of 0.17 micrograms (µg) per kilogram of body weight per day for acrylamide exposure to minimize cancer risk. For a person weighing 70 kg (about 154 lbs), this equates to about 26 µg per day
• United States (EPA): The EPA has established an oral reference dose (RfD) of 0.002 mg/kg/day (which is 2 µg/kg/day), based on non-cancer effects such as nerve damage
• California Proposition 65: The Maximum Allowable Dose Level (MADL) is 140 µg per day

Acrylamide is considered a probable carcinogen, and so there is no truly "safe" level of exposure to a carcinogen.

Many carcinogens are toxic at very low levels becuase in minute quantities they can damage cells without killing them which increases mutagenicity.

Most people’s dietary intake of acrylamide is well below these regulatory limits, but certain foods (like large servings of French fries or potato chips) can exceed the EU benchmark in a single meal

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In summary, acrylamide forms in foods when they are cooked at high temperatures, is found mainly in plant-based foods, and has potential toxicity at high exposures, but most people’s diets do not reach levels shown to cause harm in humans. Regulatory agencies recommend minimising exposure where possible.

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