Deoxynivalenol

Deoxynivalenol (DON), commonly known as vomitoxin, is a mycotoxin produced by Fusarium fungi that frequently contaminates cereal grains such as wheat, maize, and barley. 

Due to its heat stability, DON persists in processed foods, raising concerns about its effects on gastrointestinal health, immune function, and neuroinflammation in both humans and animals.

What is Deoxynivalenol (DON)?

Deoxynivalenol (DON), or vomitoxin, is a trichothecene mycotoxin produced by Fusarium fungi. It commonly contaminates grains such as wheat, barley, oats, rye, and maize. Due to its heat stability, DON persists in processed foods, posing risks to human and animal health. 

Alongside DON, its acetylated derivatives—3-acetyl-DON (3-ADON) and 15-acetyl-DON (15-ADON)—and plant-modified DON-3-glucoside contribute to toxicity. 

15-ADON is the most toxic of these compounds, with greater effects on intestinal barrier function and systemic inflammation.

Human Health Risks

DON is associated with health risks in both humans and animals:

Exposure and Toxicity

The tolerable daily intake (TDI) is 1 μg/kg body weight (bw) per day, based on reduced body weight gain in mice.

Acute exposure (≥ 8 μg/kg bw per meal) can cause nausea, vomiting, diarrhea, and abdominal pain.

Chronic exposure regularly exceeds the TDI in infants, toddlers, and children, raising significant concerns for immune function, growth, and metabolic health.

Maternal exposure to DON has been linked to lower birth weight, shorter birth length, and an increased risk of small-for-gestational-age (SGA) infants and infant mortality.

Key Mechanisms of Toxicity

Key toxicity mechanisms include:

• Ribosome Binding → inhibits protein synthesis, triggering ribotoxic stress and activating inflammatory pathways.
• Intestinal Barrier Disruption → 15-ADON has the most potent effect on gut permeability, decreasing tight junction proteins (claudin-3, claudin-4) and increasing gut inflammation.
• Neuroinflammatory Response → DON increases proinflammatory cytokines (IL-1β, IL-6, TNF-α) in the brain, contributing to anorexia, nausea, and altered neurotransmitter function (serotonin and dopamine).

Clinical Presentation of DON Exposure

Symptoms of acute exposure can include:

• Gastrointestinal distress: nausea, vomiting, diarrhea, cramping.
• Neurological effects: dizziness, headache, fever.

Symptoms of chronic exposure can include:

• Growth impairment: in children and developing fetuses.
• Immune suppression: increased infection risk.
• Metabolic disruption: linked to weight fluctuations and altered insulin sensitivity.
• Reproductive toxicity: increased risk of poor fetal growth outcomes in pregnant women with high DON exposure.

Animal Health Risks

Affected species may include:

• Highly sensitive: pigs and farmed fish (severe feed refusal, weight loss, gastric lesions, immune dysfunction).
• Moderately tolerant: poultry, horses, rabbits (growth impairment, metabolic disruption at high doses).
• Resistant: ruminants (cattle, sheep, goats) metabolize DON into less toxic forms.
• Acute sensitivity: cats and mink (vomiting, immune suppression at low exposure).

Human exposure through animal products (milk, meat, eggs) is negligible due to low DON bioaccumulation in animal tissues.

DON's Effects on Human Health

System-based effects of DON exposure in humans may include;

DON and the Brain: Neurological Effects

Emerging research highlights DON's direct impact on the brain, influencing appetite, neurotransmission, and neuroinflammation:

Appetite Suppression & Nausea: DON activates brainstem structures, leading to anorexia and nausea.

Neuroinflammation: DON increases IL-1β, IL-6, and TNF-α, promoting sickness behavior and metabolic dysregulation.

Neurotransmitter Disruptions: DON alters serotonin and dopamine pathways, contributing to mood changes, appetite loss, and stress reactivity.

Intestinal Toxicity and Barrier Disruption

DON and its acetylated derivatives directly damage gut barrier function, with 15-ADON showing the highest toxicity:

Cell Proliferation: 15-ADON inhibits intestinal epithelial cell growth more than DON or 3-ADON.

Barrier Function: 15-ADON decreases transepithelial electrical resistance (TEER), increasing paracellular permeability and gut inflammation.

Tight Junction Integrity:

• 15-ADON markedly reduces claudin-3 and claudin-4 expression, weakening intestinal integrity.
• DON and 3-ADON have milder effects, but chronic exposure can still promote leaky gut and systemic inflammation.

Clinical Implications of DON Exposure

DON exposure may exacerbate inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and food sensitivities due to its effects on the gut lining.

Increased gut permeability allows microbial toxins and dietary antigens to enter circulation, contributing to chronic inflammation, autoimmunity, and metabolic disorders.

Pregnant women may be at higher risk of inflammatory and metabolic complications from DON-related gut dysfunction.

Who Should Get Tested for Deoxynivalenol Exposure?

DON testing is not a routine clinical test but may be considered in specific populations:

Individuals with suspected mycotoxin exposure and/or mycotoxin-related food poisoning: testing may be warranted in cases of gastrointestinal illness where DON contamination is suspected and other causes have been ruled out.

Occupational health monitoring: workers in grain processing, agriculture, and animal feed production may undergo periodic testing to assess exposure levels.

Research studies on mycotoxin exposure: DON testing may be used in epidemiological studies to investigate the impact of mycotoxin exposure on human health.

Routine testing for the general population is not recommended unless specific symptoms, risk factors, or exposure concerns are present.

Testing Procedure and Interpretation

Urine mycotoxin testing detects the presence of mycotoxins and their metabolites excreted by the body, providing a direct measure of recent exposure. This test may be useful for assessing acute or ongoing exposure to mold toxins but may not reflect total body burden, as detoxification capacity varies among individuals. 

Urine samples may be collected in a clinical setting or from the comfort of home; a first-morning void is often recommended.

Serum immune response testing evaluates the body's reaction to mycotoxins by measuring antibodies (IgG, IgA, IgE) against specific mold toxins. This test requires a blood draw via venipuncture and indicates past or chronic exposure and potential immune system activation.

Combining both tests may offer a more comprehensive assessment of mycotoxin-related health effects.

Reference Range

It is important to consult the laboratory company used for their recommended reference range. In general, levels of DON or of antibodies sensitized to DON are expected to be negative, or very low. 

What Do High Levels of DON (or its Metabolites) Mean?

Elevated DON levels in biological samples (urine, blood) may indicate recent or current exposure, biological persistence, or an immune response against these compounds. 

The presence of DON metabolites, such as de-epoxy-deoxynivalenol (DOM-1), provides a clearer picture of recent ingestion or inhalation of contaminated material.

High levels of DON can be associated with acute mycotoxicosis.

What Do Low Levels of DON (or its Metabolites) Mean?

Low or undetectable levels of DON metabolites may indicate:

• Minimal or no recent exposure to contaminated food or grain dust
• Background exposure from small amounts of DON present in processed foods

While low DON levels suggest lower immediate risk, chronic low-level exposure remains an area of research, particularly concerning its potential effects on immune function and gut health over time.