Do we eat plastic in our food?

In this brief guide, we are going to answer the question “Do we eat plastic in our food?” and discuss the seriousness of the plastic issue these days.

Do we eat plastic in our food?

Sadly yes. We are eating plastic mainly in drinking water, but also through seafood (saltwater fish, crustaceans, and shellfish), freshwater fish, beer, and salt. Plastics in heterogeneous mixture of differently shaped materials referred to as fragments, fibers, spheroids, granules, pellets, flakes or beads, in the range of 0.1–5,000 micrometers are found in the seas and food chains all around the world with very few exceptions. They are originated by release of fibers from clothes or by continuous fragmentation of plastics disposal in the environment (1,2).

The University of Newcastle (Australia) conducted a study looking at global data from more than 50 other studies of people’s intake of microplastics. Microplastics have been detected in seafood, tapwater, beer, honey, sugar and salt (2).

The results demonstrate how worrisome this issue is, in addition to presenting an important step towards understanding the impact of plastic on our lives.

The study also confirms the urgent need to address ways of not polluting ecosystems with plastic, thereby alleviating the problems they can cause.

How much plastic do we eat?

A study commissioned by the WWF and conducted by the University of Newcastle, suggests that people are consuming around 2,000 tiny pieces of plastic every week (microplastic), which is the equivalent weight of a credit card.

This means we are ingesting approximately 21 grams per month and just over 250 grams per year. In fish, the average number of particles found per fish is between 1 and 7. In shrimp, an average of 0.75 particles/g is found. In bivalves, the average number of particles is 0.2–4 (median value)/g. Average content of microplastics reported for honey are 0.166 fibers/g and 0.009 fragments/g. In beer, fibers, fragments and granules have been found at the following amounts 0.025, 0.033 and 0.017 per mL, respectively. For table salts, microplastic content of between 0.007 and 0.68 particles/g have been found (1).

Is the distribution of plastics in water and food the same across the Earth?

No, it is not. There are wide regional variations in plastic intake.

For example, in the United States or India, the consumption of plastic in the water is about twice the amount of plastic found in water in Europe or Indonesia.

These differences are due to the habits of the population, such as the amount of single-use plastics commonly used, as well as how much recycling is carried out, the regulatory laws of each country, among other factors.

A recent study revealed the microplastic debris contribution by certain geographical areas accordingly, Southeast Asia (15.9%), North America (17.2%), and Africa and Middle East (8.7%) (3).

 What kind of plastic are we eating?

We are eating a type of plastic called microplastic. Microplastics are small pieces of plastic less than five millimeters in length. The most commonly found polymers include low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), and polyvinyl chloride (PVC), while other polymers such as nylon, acrylic, polyurethanes, polylactic acid and polycarbonate (3).

Where does microplastic come from?

Microplastics can easily spread through ocean waters coming from continental rivers, harming all the environmental flora and fauna.

Microplastics that reach the ocean can be classified into primary and secondary.

The so-called primary ones can originate from the inadequate disposal of products formed by pellets, washing of clothes made of plastic fibers, use of personal hygiene products, residues from tire erosion, among others. For example, the friction from washing machines causes polymer fibers in the clothes to be released, reaching sewers and eventually rivers (2).

Meanwhile, the secondary ones are the degradation products of macroplastics, which, once abandoned in nature, end up being fragmented by physical-chemical or biological processes, through prolonged exposure to ultraviolet (UV) light and physical abrasion. Secondary microplastics can originate from land-based or sea-based sources. Sea-based sources include fishing equipment and sewage from ships. Land-based sources could be plastic bags, packaging materials or waste from the plastic industry (1).

Microplastics can be vectors of toxic compounds, which cause endocrine or carcinogenic problems in organisms that come into contact with these substances.

They can also alter the physical properties of sediments on beaches or sediments on the seafloor, modifying water flow and nutrient distribution, causing problems for marine species.

Furthermore, they can be vectors of exotic species and pathogens that can unbalance and endanger the biodiversity of marine ecosystems.

Finally, microplastics can be confused with food and ingested by many species, leading to eating disorders, blockages in the intestinal tract, physiological problems, or reproductive problems, in addition to being bioaccumulative in the food chain.

There is a lack of information on the fate of micro- and nanoplastics in the gastrointestinal (GI) tract. In the case of dietary intake, important questions are whether after ingestion micro- and nanoplastics are confined to the gut lumen or whether translocation across the gut epithelium takes place. Translocation would imply that internal organs and tissues are exposed to these particles. Whether nanoplastics can be formed from degradation of microplastics under the conditions of the human GI tract is not known. The available data on toxicokinetics only include absorption and distribution, whereas no information is available on metabolism and excretion (1).

Summarizing the history of plastic

The first synthetic plastic was produced in 1907 by Leo Baekeland, revolutionizing the chemical industry, and serving as a basis for the development of other materials.

In the ’70s, polymers began to be produced industrially.

With the exponential growth of production, combined with the lack of proper destination and high resistance to degradation, it is estimated that in 1950 the number of plastics and fish in the oceans will be the same.

Is plastic a threat to our health?

Yes, plastic can cause a lot of problems to our health. Although research linking the consumption of microplastics with human health problems is still recent. There is still not enough data to say exactly how they affect us.

Still, researchers suspect that ingesting microplastics could expose us to certain chemicals found in some plastics that are already known to be harmful to human health. On average, 4% of the weight of the plastics predominantly found in microplastics are additives (1). Plastic debris can be regarded as complex cocktails of contaminants, including chemical additives, residual monomers and ambient chemical substances adsorbed to the plastic surface. Many of these pollutants (such as bisphenol A, phthalates and some brominated flame retardants) are considered as endocrine disruptors that can cause severe health problems (2).

These chemicals (phthalates, BPA – bisphenol A, BPS – bisphenol S) are considered endocrine−disrupting chemicals (EDCs) and have been linked to a variety of health problems, including reproductive harm, obesity, breast cancer, blood infection, as well as issues such as organ problems and developmental delays in children.

How can we help reduce the amount of plastic in the environment?

We produce hundreds of millions of tons of plastic every year, most of which cannot be recycled. We need to use less plastic, move towards environmentally sustainable products and services, and create technology that recycles plastic more efficiently. Furthermore, as a society, we need to pressure industries for materials that are less harmful to the environment. And demand greater regulation from our governments to preserve our well-being and health.

Conclusion

In this article, we answered the question “Do we eat plastic in our food?”. In addition, we discussed the effects of this unwanted ingestion, evaluated how plastic gets to our table, and mentioned the main sources of consumption of these materials.

If you have any questions or comments please let us know.

Citations

1. EFSA Panel on Contaminants in the Food Chain (CONTAM). Presence of microplastics and nanoplastics in food, with particular focus on seafood. Efsa Journal, 2016, 14, e04501.
2. Conesa, Juan A., and Maria E. Iñiguez. Analysis of microplastics in food samples. Handbook of Microplastics in the Environment. Cham: Springer International Publishing, 2022. 377-391.
3. Ajith, N., Arumugam, S., Parthasarathy, S. et al. Global distribution of microplastics and its impact on marine environment—a review. Environ Sci Pollut Res, 2020, 27, 25970–25986.