What are the harmful chemicals in wheat?

November 9, 2025 •

4 min read

According to the Food and Agriculture Organization, mycotoxins can contaminate up to 25% of the world's cereal crops, including wheat. This raises serious questions about food safety and health, making it crucial to understand not just gluten, but all the potentially harmful chemicals in wheat.

Quick Summary

An overview of potentially harmful chemicals in wheat, from natural compounds like gluten and phytic acid to external contaminants such as heavy metals, mycotoxins, and pesticide residues like glyphosate. Examines how these substances can impact human health and discusses mitigation strategies.

Key Points

Gluten isn't the only concern: While gluten triggers autoimmune and sensitivity issues for some, other potentially harmful chemicals in wheat include natural antinutrients like phytic acid and lectins.
Environmental toxins are a factor: Wheat can absorb heavy metals like cadmium and lead from contaminated soil, and may contain residues from pesticides like glyphosate.
Mycotoxins are a risk from mold: Fungal toxins, known as mycotoxins, can contaminate wheat during growth or storage, posing risks of kidney damage and other illnesses.
Cooking introduces a chemical hazard: Acrylamide, a potential carcinogen, forms in wheat-based products when they are cooked at high temperatures, not in the raw grain itself.
Antinutrients reduce mineral absorption: Phytic acid, concentrated in whole wheat bran, can bind to essential minerals like zinc, iron, and calcium, reducing their bioavailability.
Mitigation involves the entire supply chain: Reducing harmful chemicals requires controlling soil and water quality, proper crop management, monitored storage, and refining industrial processes.

Antinutrients in Wheat: Natural Chemicals

Beyond the well-known protein gluten, wheat contains several naturally occurring compounds, often referred to as antinutrients, that can affect human health. While some individuals tolerate these without issue, others may experience adverse effects.

Gluten and Its Protein Components

Gluten is not a single chemical but a complex of two main protein groups: gliadins and glutenins. When flour is mixed with water, these proteins form an elastic network, giving dough its characteristic texture. For some, however, gluten triggers a range of health problems:

Celiac Disease (CD): An autoimmune disorder in genetically predisposed individuals where consuming gluten leads to an immune response that damages the small intestine.
Non-Celiac Gluten Sensitivity (NCGS): A condition with symptoms similar to celiac disease (bloating, abdominal pain, fatigue) but without the autoimmune intestinal damage.
Wheat Allergy: An IgE-mediated allergic reaction to wheat proteins, including gluten, that can cause symptoms from skin rashes to anaphylaxis.

Phytic Acid (Phytates)

Phytic acid is the primary storage form of phosphorus in many plant tissues, particularly concentrated in the bran of whole grains. While it has some beneficial antioxidant properties, it is primarily known as an antinutrient that binds to important minerals such as iron, zinc, calcium, and magnesium. This binding prevents their absorption in the gastrointestinal tract, potentially leading to mineral deficiencies over time.

Lectins

Wheat germ agglutinin (WGA) is a type of lectin found in wheat. Lectins are proteins that bind to carbohydrates and can resist degradation in the gut. Some studies suggest that WGA can contribute to gut inflammation, though its impact is highly debated and often depends on cooking methods and individual sensitivity. Cooking and processing can reduce lectin activity, but some may remain active.

Environmental Contaminants and Toxins

Wheat, like any crop, is susceptible to absorbing various environmental pollutants and contaminants, both during growth and post-harvest. The presence of these chemicals is often linked to farming practices, industrial pollution, and storage conditions.

Mycotoxins: Fungal Contaminants

Mycotoxins are toxic compounds produced by certain types of fungi that can grow on wheat, especially in humid conditions or after prolonged storage. Key mycotoxins found in wheat include:

Deoxynivalenol (DON), also known as vomitoxin, produced by Fusarium fungi.
Ochratoxin A (OTA), which can have destructive effects on the kidneys at high levels.
T-2 and HT-2 toxins, produced by Fusarium species. Monitoring and control measures are in place to manage mycotoxin levels, but contamination can be unavoidable.

Heavy Metals

Wheat can accumulate potentially toxic elements (PTEs) like arsenic, cadmium, lead, and nickel from contaminated soil and water. Studies have found significant non-carcinogenic risks associated with PTE exposure, particularly in children. While milling can remove some of these metals by separating the outer bran layer, contamination can occur from environmental exposure or equipment abrasion during processing.

Pesticide Residues (Glyphosate)

Herbicides like glyphosate are commonly used in modern agriculture, sometimes as a pre-harvest desiccant. Some studies suggest glyphosate exposure may be linked to certain health issues, including potential disruption of gut bacteria and nutrient absorption. The practice of timely application, as opposed to premature use, can significantly impact residue levels in wheat.

Acrylamide

Acrylamide is not present in raw wheat but can form during high-temperature cooking, such as baking, roasting, or frying, of wheat-based products like bread and crackers. It forms from the reaction between sugars and the amino acid asparagine. Reducing acrylamide levels in processed wheat foods is an ongoing focus for food safety organizations.

Comparison of Harmful Chemicals in Wheat


Chemical/Type	Origin	Health Impact	Mitigation/Control	Found in
Gluten	Natural protein	Celiac disease, non-celiac sensitivity, allergic reactions.	Dietary avoidance for sensitive individuals.	Endosperm (higher in refined flour).
Phytic Acid	Natural compound (antinutrient)	Inhibits mineral absorption (zinc, iron, calcium).	Fermentation, germination, soaking, milling.	Outer bran layer (higher in whole wheat).
Mycotoxins	Fungal contamination	Kidney damage (OTA), gastrointestinal illness (DON), immune suppression.	Good agricultural practices, proper drying and storage.	Inconsistent; can be present in grain due to field or storage contamination.
Heavy Metals	Environmental (soil, water)	Carcinogenic and neurotoxic risks, organ damage.	Soil management, water treatment, milling effectiveness.	Outer bran layers, varies by origin.
Glyphosate	Herbicide residue	Potential disruption of gut bacteria and nutrient absorption.	Proper application timing, agricultural monitoring.	Varies based on farming practices.
Acrylamide	Formed during cooking	Potential carcinogenic and neurotoxic effects.	Lower temperature cooking, processing interventions.	Baked and fried wheat products.

Conclusion

While wheat provides significant nutritional value, it is also associated with several potentially harmful chemicals that can affect human health. Some, like gluten and phytic acid, are naturally occurring compounds that primarily pose risks to sensitive individuals or can impact mineral absorption, especially with high whole-grain consumption. Others, such as heavy metals and mycotoxins, are environmental contaminants, emphasizing the importance of modern farming practices, soil monitoring, and controlled storage. Pesticide residues like glyphosate represent another area of concern related to agricultural methods. Lastly, the cooking process itself can introduce chemicals like acrylamide in wheat-based products. For consumers, understanding the origins and effects of these various chemicals allows for informed dietary choices, including opting for properly prepared whole grains, monitoring intake, or exploring gluten-free alternatives if necessary. Continued vigilance in food safety regulations and agricultural practices is essential to minimize exposure and protect public health. Learn more about the environmental factors affecting wheat contamination from this study.

Acknowledgment

This article is for informational purposes only and does not constitute medical advice. Consult with a healthcare professional or registered dietitian for personalized dietary guidance.

Frequently Asked Questions

Celiac disease is an autoimmune disorder where consuming gluten damages the small intestine. Gluten intolerance (or non-celiac gluten sensitivity) causes similar symptoms but does not involve the same autoimmune damage to the gut lining.

Heavy metals, including cadmium, lead, and arsenic, can be absorbed by the wheat plant from contaminated soil, water, and atmospheric deposition. Industrial pollution and some agricultural practices are sources of this contamination.

Proper cooking can reduce some harmful compounds, like certain lectins. However, some toxins are resistant to heat, and in the case of acrylamide, high-temperature cooking is what creates the chemical in the first place. It does not eliminate heavy metals or mycotoxins.

Whole wheat, which includes the bran, contains higher levels of natural antinutrients like phytic acid because this compound is concentrated in the bran layer. Similarly, heavy metals are often more concentrated in the bran, meaning refined wheat flour typically has lower levels of these contaminants.

Traditional preparation methods can help reduce antinutrients like phytic acid. These include soaking, sprouting, and fermenting wheat, which activate enzymes that break down phytic acid. Opting for sourdough bread is one such example.

No, glyphosate is not found in all wheat products. Its presence depends on agricultural practices, particularly if and when the herbicide is applied. Residue levels can vary significantly, and proper application timing is crucial.

Mycotoxins are not always present, but contamination is a significant risk, especially in warm, humid climates or with improper storage. Global monitoring and strict regulations are in place to manage the risk, but the possibility of contamination remains.