Your Favorite Takeout Coffee May Have A Subtle Detail You Haven't Noticed

• 3.09.2026, 8:45

Scientists have identified the cause.

Disposable paper cups used for coffee, tea, and other hot beverages can be a source of micro- and nanoplastics. A new study has shown that when exposed to hot liquids, the inner plastic lining of such containers can release millions of tiny particles.

This was reported by the Daily Mail.

Despite their name, disposable paper cups are usually made of more than just paper. To prevent them from getting soggy or leaking when they come into contact with beverages, their inner surface is coated with a thin layer of plastic. It is this coating that scientists have identified as a previously underestimated source of microplastic pollution.

What the experiment showed

As part of the study, scientists tested two types of disposable cups. One had an inner coating of polyethylene (PE)—a plastic made from fossil fuels. The other was coated with polylactic acid (PLA), which is considered a biodegradable material.

To simulate typical conditions for using such cups, the researchers filled them with hot water. After a short period of contact with the cup walls, the liquid was analyzed to determine how many plastic particles had leached into it.

It turned out that the water from the cups with a polyethylene coating contained about 2.7 million plastic particles per milliliter. At the same time, the PLA-coated cups released even more—approximately 4.3 million particles per milliliter.

The difference became even more pronounced when the scientists assessed not the number but the total mass of plastic in the water. In the case of PLA-coated cups, it was 12 times greater than in the samples with a polyethylene coating. The study’s authors attribute this to the fact that the particles released by polylactic acid were larger.

At the same time, a co-author of the study, environmental scientist Elvis Okoffo from the University of Queensland, cautioned against drawing definitive conclusions. According to him, the results do not mean that people should completely stop using paper cups, nor do they prove that PLA itself poses a danger.

However, the question of the potential impact of plastic particles on the human body remains understudied. Okoffo also pointed out that the chemicals in plastic are not intended for human consumption.

What Is Known About Microplastics

Microplastics are defined as plastic particles ranging in size from one micrometer to five millimeters. Nanoplastics are even smaller—some particles can be about a thousand times thinner than a human hair.

Scientists have already detected micro- and nanoplastics not only in the environment but also in the human body. Due to their extremely small size, individual particles are able to cross biological barriers—particularly in the intestines, lungs, and skin—and can subsequently enter the bloodstream.

Traces of plastic particles have been detected in various human organs and tissues. Specifically, they have been found in the brain, heart, stomach, lymph nodes, placenta, and testicles. Food and beverages may be one source of microplastics entering the body.

At the same time, scientists are still investigating what health consequences the accumulation of such particles may have. In laboratory studies on animals and cells, exposure to microplastics has been linked to inflammatory processes, immune system dysfunction, and damage to cells and tissues.

Some scientific studies have also mentioned a possible link between microplastics and disruptions in the functioning of the reproductive, digestive, and respiratory systems. In addition, researchers have pointed to a possible increased risk of heart attack and stroke.

However, there are no definitive conclusions yet regarding the long-term effects of microplastics on human health. The available data are insufficient, so research into the possible consequences of their accumulation in the body is ongoing.

What Scientists Suggest

The study’s authors emphasize that the findings are not a call to completely abandon disposable paper cups. In their view, however, when evaluating materials that come into direct contact with food and beverages, one should consider more than just their environmental impact.

The scientists suggest further studying the amount of micro- and nanoplastics that such materials can release during normal use. This is especially true for packaging and disposable tableware that come into contact with hot beverages.

In addition, researchers see room for improvement in the paper cups themselves. Specifically, manufacturers could develop internal coatings that release fewer plastic particles when in contact with hot liquids.

As a reminder, cantaloupe and watermelon can cause bloating, stomach pain, and diarrhea even when eaten fresh. We previously reported that fructose may be the cause of these unpleasant reactions.