PESTICIDES AND PLASTICS – DETRIMENTAL EFFECTS ON HUMAN HEALTH

In today’s world, we are surrounded by man-made chemicals. Two chemicals that need special attention are glyphosates and plastics. These substances are part of a group called “xenobiotics”, which simply means chemicals that are not naturally produced by the body. Thousands of xenobiotics can enter the food chain, either intentionally as additives (such as flavourings, colourants, preservatives or emulsifiers) or unintentionally as contaminants (such as toxins, herbicides, plastics or pollutants).

Pesticides, include glyphosates and are widely used as weedkillers (common name: Roundup™) in agriculture. Plastics on the other hand, are used in packaging, bottles, clothing and many everyday items, including sanitary pads, beauty products and even toothpaste.

Our oceans and rivers are polluted with plastic waste like never before!

While these chemicals have made life more convenient, research from South Africa, including work supported by the University of the Free State, suggests that long-term exposure may affect our health in subtle but important ways.

HOW ARE WE EXPOSED TO THESE SUBSTANCES

Most people are exposed daily without realising it. Glyphosates enter the body mainly through food and water. They are found in crops such as wheat, maize, soya and beans and have even been detected in breast milk.

Plastics break down into tiny particles called microplastics and nanoplastics. These have been found in human blood, tissues and even the placenta. The harmful effects of plastic exposure have been well documented in animals, particularly in fish and other aquatic species, but the effects in humans are less well researched.

A growing body of evidence shows that microplastics and nanoplastics can pass through the human body’s natural barriers. They are able to move through tissues, travel to distant organs and easily build up in different parts of the body.

Research from the University of the Free State also highlights that everyday items, including certain sanitary products, may expose people to hormone-disrupting chemicals within these products. Over time, this adds to the overall level of exposure.

WHAT HAPPENS INSIDE THE BODY?

Once inside the body, these substances can interfere with normal biological processes. Studies suggest that glyphosates and microplastics may:

• Trigger inflammation
• Increase harmful oxidative stress
• Damage DNA
• Disrupt the immune system

It is important to note that immediate harmful effects to these chemicals may not always be apparent, but even at low levels, repeated exposure over many years can lead to cumulative effects.

HOW DO THEY AFFECT THE GUT?

The gut plays a central role in overall health. It contains beneficial bacteria that help with digestion and regulate the immune system. Glyphosates may disturb this balance by reducing helpful bacteria and allowing harmful ones to grow. This imbalance is known as dysbiosis. Microplastics may also damage the lining of the gut. Research suggests they can:

• Weaken the gut barrier
• Reduce nutrient absorption
• Interfere with digestion

This may result in what is often referred to as a “leaky gut”, where unwanted substances pass into the bloodstream.

CAN THIS LEAD TO ALLERGIES?

Yes—this is one of the key concerns.

A healthy gut helps the immune system learn what is harmless and what is harmful. When the gut is disrupted:

• The immune system may overreact
• Harmless foods may be treated as threats
• Allergies may develop

Microplastics may worsen this process. They can attach to food proteins and make it easier for them to enter the body, increasing the likelihood of allergic reactions.

HOW DO PLASTICS AFFECT HORMONES?

Many plastics contain chemicals known as endocrine disruptors, such as phthalates and bisphenols.

Research linked to the University of the Free State shows that:

• These chemicals are present in many everyday products
• They can enter the body through repeated use and skin contact
• Even low levels of daily exposure may build up over time

These substances can interfere with the body’s hormone system, which controls growth, metabolism and immune function. Because hormones and the immune system are closely connected, disruption may increase inflammation and make allergic conditions more likely.

ARE THERE OTHER HEALTH RISKS?

There is increasing evidence linking long-term exposure to several health concerns, including certain cancers in some studies, although this remains debated. Microplastics have also been linked to gut inflammation, reduced absorption of vitamins and worsening of inflammatory bowel conditions.

Studying the long-term effects of these substances in humans is challenging, as many related health conditions develop gradually over years or even decades, making it difficult to establish a clear cause-and-effect relationship.

WHAT CAN WE DO TO REDUCE EXPOSURE?

Small, consistent changes can make a meaningful difference over time.

Although it is not possible to avoid these substances completely, practical steps can help reduce exposure:

• Wash fruit and vegetables thoroughly
• Choose fresh, unpackaged foods where possible
• Avoid heating food in plastic containers
• Use glass or stainless steel instead of plastic
• Reduce the use of single-use plastics
• Be mindful of everyday products that may contain harmful chemicals

ALL of us should be strong advocates for action against pollution.

WHAT DOES THIS MEAN FOR THE FUTURE?

Glyphosates and plastics are now part of modern life. Research, including important contributions from South African scientists, suggests that these substances may affect the gut, immune system, and hormones. This may help explain the increasing rates of allergic diseases worldwide.

Further research is needed, particularly regarding long-term, low-level exposure. However, reducing exposure where possible is a sensible and practical approach. Greater awareness, combined with simple lifestyle changes, can help protect both current and future generations.

See video Pesticides, Plastics & Your Health

References

1. Sobral AF, Cunha A, Costa I, Silva-Carvalho M, Silva R, Barbosa DJ. Environmental Xenobiotics and Epigenetic Modifications: Implications for Human Health and Disease. J Xenobiot. 2025;15(4):118. https://doi.org/10.3390/jox15040118.
2. Peillex C, Pelletier M. The impact and toxicity of glyphosate and glyphosate-based herbicides on health and immunity. J Immunotoxicol. 2020;17(1):163-174. https://doi.org/10.1080/1547691X.2020.1804492.
3. Boissiere-O’Neill T, Casas M, Philippat C, et al. Phthalates and bisphenols early-life exposure, and childhood allergic conditions: a pooled analysis of cohort studies. J Expo Sci Environ Epidemiol. 2025. https://doi.org/10.1038/s41370-025-00790-2.
4. Blignaut J, Kemp G, Erasmus E, Visser HG, Schutte-Smith M. The presence of endocrine disrupting chemicals in sanitary pads: A study done in South Africa. Sci Total Environ. 2026;1018:181510. https://doi.org/10.1016/j.scitotenv.2026.181510.