Is Eating Dirt Good for Your Immune System? The Surprising Link Between Soil and Gut Health

November 17, 2025 •

4 min read

According to a 2024 review, contact with environmental microorganisms, especially from soil, has decreased dramatically with modern lifestyles. This reduced exposure has coincided with a rise in chronic inflammatory diseases, sparking the question: is eating dirt good for your immune system?

Quick Summary

The practice of eating dirt, or geophagy, is not a safe way to boost immunity due to significant risks like heavy metal poisoning and parasitic infections. However, research suggests that safe exposure to diverse soil microbes, particularly in childhood, can positively influence gut microbial diversity and immune function. The key lies in controlled exposure, not direct consumption of potentially contaminated soil.

Key Points

Geophagy is Risky: Intentionally eating dirt (geophagy) is dangerous due to potential exposure to parasites, pathogens, and heavy metal toxins.
Immune System 'Training': Safe, incidental exposure to environmental microbes, such as from gardening or playing outdoors, can help train and regulate the immune system, potentially reducing the risk of allergies and autoimmune diseases.
Gut-Soil Connection: Scientific evidence shows a link between the biodiversity of soil and the diversity of the human gut microbiome; a more diverse gut microbiome is generally associated with better health outcomes.
Not for Nutritional Deficiencies: While some people with mineral deficiencies like iron or zinc crave dirt (pica), eating soil can actually inhibit nutrient absorption, worsening the problem.
Risks Outweigh Benefits: Any anecdotal or historical benefits linked to consuming specific clays (kaolin) for digestive issues are far outweighed by the significant risks of intestinal blockage, infection, and poisoning.
Children Need Safe Exposure: Encouraging children to play in clean, natural outdoor settings is beneficial for their developing immune systems, but deliberate soil ingestion should be prevented.

The 'Hygiene Hypothesis' and Immune System Development

For decades, the "hygiene hypothesis" has posited that reduced early-life exposure to microorganisms and parasites can lead to a less robust, and sometimes overactive, immune system. This idea has been supported by studies showing lower rates of allergies and asthma in children raised on farms or with pets. The exposure to a rich microbial environment during development helps train the immune system to recognize and tolerate harmless foreign invaders, preventing it from overreacting to common allergens. The microbiome, the vast community of microorganisms living in and on our bodies, plays a critical role in this process.

The Human Gut-Soil Microbiome Connection

There is increasing evidence supporting a strong connection between the soil microbiome and the human gut microbiome. Humans evolved in close contact with soil, which served as a crucial reservoir of microorganisms. Our gut microbial diversity has decreased significantly with urbanization and modern sanitation, and some research suggests this is linked to the rise in immune-mediated diseases. Studies on gardening families and children in nature-oriented daycares have found that greater contact with biodiverse soil can lead to higher gut microbial diversity and increased levels of anti-inflammatory markers.

The Difference Between Incidental Exposure and Intentional Consumption (Geophagy)

It's crucial to distinguish between incidental microbial exposure from the environment and the intentional consumption of dirt, a practice known as geophagy. While the former can be beneficial, the latter carries significant and documented health risks.

Incidental Exposure (Generally Safe)

Playing in the dirt or garden.
Eating produce with trace amounts of soil (after washing).
Being around farm animals.

Intentional Consumption (Geophagy)

Deliberately eating loose dirt, clay, or soil.
This is often linked to pica, a condition driven by nutritional deficiencies or mental health factors.

Potential Benefits of Soil-Based Organisms (SBOs)

While eating dirt is ill-advised, the beneficial microorganisms found within soil, known as Soil-Based Organisms (SBOs), are the focus of much research. These microbes play a vital role in gut health and immune regulation. SBOs are not consumed directly from the ground but are used in some probiotic supplements. Some of their purported benefits include:

Boosting Gut Flora: SBOs can help increase the diversity of the gut microbiome, which is often depleted in people with modern lifestyles.
Producing Beneficial Compounds: Certain soil-based bacteria produce essential compounds like short-chain fatty acids (SCFAs) that nourish colon cells and support gut barrier integrity.
Modulating Inflammation: Exposure to specific soil microbes has been shown to increase anti-inflammatory markers and regulate the immune system's response.
Enhancing Stress Resilience: Some soil-derived bacteria, like Mycobacterium vaccae, have been linked to reduced anxiety and enhanced stress resilience in animal models.

Comparison of Ingesting Dirt vs. Safe Microbial Exposure


Feature	Ingesting Dirt (Geophagy)	Safe Microbial Exposure (e.g., gardening)
Immune Impact	High risk of parasitic and pathogenic infection.	Potential for training immune system and increasing beneficial gut diversity.
Risk of Contaminants	High risk of heavy metal poisoning (lead, arsenic) and pesticides.	Minimal risk if in a known clean environment (garden), can be managed by hand hygiene and washing produce.
Gastrointestinal Effects	Risk of constipation, intestinal obstruction, and nutrient malabsorption.	Supports healthy gut barrier function and microbial diversity.
Nutrient Absorption	Can interfere with the absorption of essential nutrients like iron and zinc.	Indirectly supports better nutrient absorption by promoting a healthier gut microbiome.
Infection Risk	Significant risk of infections from bacteria, fungi, and parasites like helminths.	Low risk of infection, promotes a balanced immune response.
Safety for Vulnerable Groups	Extremely dangerous for pregnant women, children, and immunocompromised individuals.	Considered safe and beneficial for children in controlled, natural play settings.

Risks of Eating Dirt

Despite a perceived connection between soil and health, the deliberate eating of dirt is hazardous due to multiple risks.

Parasites and Pathogens: Soil can harbor dangerous parasites (like helminths) and pathogenic bacteria (E. coli), which can lead to serious infections, diarrhea, and nutritional deficiencies.
Heavy Metal Poisoning: Contaminated soil can contain toxic heavy metals such as lead, arsenic, and mercury, causing poisoning with long-term consumption.
Digestive Issues: Eating dirt can cause constipation, intestinal blockages, and damage to the digestive tract.
Nutrient Binding: Certain clays in soil can bind to vital minerals like iron and zinc in the digestive tract, hindering their absorption and potentially worsening anemia.
Toxic Chemicals: Soil may contain pesticides, fertilizers, and other chemical contaminants that are harmful if ingested.

The Bottom Line: Focus on Safe Exposure, Not Consumption

While the underlying premise—that exposure to soil microbes benefits immune function—has merit, the practice of actually eating dirt is a dangerous and misguided approach. The risks of consuming parasites, heavy metals, and other contaminants far outweigh any potential benefits. The healthy way to engage with the natural microbiome is through activities like gardening, playing in clean outdoor environments, and eating washed, home-grown produce. For those with underlying cravings (pica), a medical professional should be consulted to address any potential nutritional deficiencies or psychological factors. The modern world's over-sanitization may have consequences for our immune systems, but the solution is safe, natural exposure, not the perilous practice of geophagy.

Conclusion: Responsible Engagement with Nature is Key

So, is eating dirt good for your immune system? No, intentional consumption carries severe health risks. However, the connection between a diverse environmental microbiome and a healthy immune system is well-supported by scientific research. Safe, responsible interaction with natural environments, especially for children, is a powerful tool for promoting immune tolerance and resilience. The modern push for excessive hygiene may have diminished our microbial diversity, but we can restore it by embracing outdoor activities and fostering biodiversity in our local green spaces. The key takeaway is to foster contact with nature—without eating it. This provides the beneficial microbial exposure our bodies evolved with, minus the dangerous contamination risks associated with geophagy.

[Disclaimer: This article provides general information and is not a substitute for professional medical advice. Always consult a healthcare provider for any health concerns or before starting new treatments.]

Frequently Asked Questions

No, eating dirt is never entirely safe. While certain beneficial microorganisms exist in soil, the risk of ingesting harmful parasites, pathogenic bacteria, heavy metals, or toxic chemicals is too high to justify intentional consumption.

Children often put non-food items in their mouths as a normal part of exploring their world, especially up to age two. Persistent dirt-eating past this age could indicate pica, a condition sometimes linked to nutritional deficiencies like iron or zinc, which should be evaluated by a doctor.

The 'hygiene hypothesis' suggests that modern, overly sterile environments can prevent the immune system from developing properly due to a lack of exposure to a diverse range of microorganisms. This can lead to an increase in allergies and autoimmune diseases.

Yes, you can. Safer alternatives include gardening, spending time in natural parks, and eating unpasteurized fermented foods or probiotics. These methods offer beneficial microbial exposure without the risk of ingesting harmful contaminants.

The health risks include parasitic infections (like helminths), bacterial illnesses (from pathogens like E. coli), heavy metal poisoning, intestinal blockages, and nutrient malabsorption.

While anecdotal evidence and cultural traditions suggest geophagy helps with morning sickness, there is little scientific support for this claim. The risks of heavy metal poisoning and infection pose a serious threat to both mother and fetus, and healthcare professionals strongly advise against it.

SBOs are beneficial microorganisms found in soil. While you should not eat dirt, some health supplements contain SBOs or related compounds. These are processed to be free of contaminants, offering a safer way to potentially support gut health.