Microplastics and gut health: What happens when we ingest them?
Microplastics—tiny plastic particles less than five millimeters wide—are now a routine part of our environment. They’ve been detected in oceans, soil, air, drinking water, and even food. That means most of us ingest small amounts of plastic regularly, often without realizing it. As researchers learn more about where microplastics go in the body, one key question is gaining attention: What happens when these particles reach the gut?
Dr. Linda Nguyen, Division Chief of Gastroenterology and Hepatology at Hoag’s Digestive Health Institute, shares her insights.
How do microplastics get into our digestive system?
“Microplastics can enter the body through everyday eating and drinking,” Dr. Nguyen says.
Common sources include:
Bottled and tap water, which may contain plastic fragments from packaging or pipes
Seafood, especially shellfish that are eaten whole
Salt, sugar, and processed foods, which can be contaminated during production
Food packaging, as plastics shed particles into hot or acidic foods
“Once swallowed, these particles course through the gastrointestinal tract, where they interact with digestive tissues and the trillions of microbes that comprise the gut microbiome.”
What happens inside the gut?
Early research suggests several ways microplastics may affect gut health:
1. Irritation of the gut lining
“Very small plastic particles can come into contact with intestinal cells,” Dr. Nguyen says. “Laboratory studies show they may trigger low-grade inflammation, which could weaken the gut’s protective barrier over time.”
2. Disruption of the microbiome
The gut microbiome plays a key role in digestion, immune function, and metabolism. Some animal studies indicate microplastics may shift the balance of “good” and “bad” bacteria, potentially contributing to digestive symptoms or reduced immune resilience.
3. Transport of harmful chemicals
“Microplastics can carry additives and environmental pollutants on their surface,” Dr. Nguyen says. “When ingested, they may release these substances into the gut, adding to the body’s chemical burden.”
4. Possible systemic effects
“Tiny particles, especially nanoplastics, may pass through the intestinal wall and enter the bloodstream,” says Dr. Nguyen. “Researchers have detected microplastics and nanoplastics in kidney, liver, and brain tissue as well as atherosclerotic blood vessels—the clinical consequences of which continue to be investigated.”
What does this mean for digestive health?
While evidence is still emerging, scientists are concerned about potential links between microplastic exposure and:
Chronic low-grade inflammation
Changes in gut permeability (“leaky gut”)
Altered nutrient absorption
Increased risk of metabolic or immune-related conditions
Because the gut is the body’s first line of contact with what we ingest, it may also be one of the first systems affected by long-term exposure.
Can we reduce exposure?
While Dr. Nguyen says it’s impossible to avoid microplastics entirely, small changes can help lower intake:
Use glass or stainless steel instead of plastic containers when possible
Avoid heating food in plastic in the microwave
Avoid plastic cutting boards
Drink filtered tap water rather than bottled water when feasible
Switch from plastic tea bags to loose-leaf tea with a metal strainer
Eat whole foods and limit highly processed foods, which may have more packaging-related contamination
Choose fresh over pre-packaged foods
“These steps may also support overall gut health by reducing exposure to other environmental contaminants,” she says.
Remember…
Microplastics are an unavoidable part of modern life, and research is still unfolding on how they affect human health. What scientists do know is that the gut is a primary point of contact—and early evidence suggests microplastics may influence inflammation, the microbiome, and the gut barrier itself. Protecting digestive health already involves good nutrition, hydration, and lifestyle habits. As understanding of microplastics grows, minimizing unnecessary plastic exposure may become another practical way to support a healthier gut from the inside out.
