How microplastics harm the heart

Indian Express

30-06-2025

— Ghanshyam Kumar and Dr Bhanu Duggal
Cardiovascular diseases (CVDs) remain one of the leading causes of death globally, and growing evidence suggests that environmental factors may be silently worsening these health risks. Some recent studies have indicated a possible link between the severity of CVDs and microplastics – tiny fragments of plastic that infiltrate the human body through drinking water, everyday food items, fishery products, etc.
In addition to CVDs, microplastics have been linked to a wide range of health issues, including gut dysfunction, respiratory complications, kidney and liver damage, reproductive and developmental problems, and even neurological disorders. Let's understand what is microplastic and what are the health risks associated with it?
Microplastics are tiny particles of less than five millimetres in size. Their pervasive presence in the air we breathe, the water we drink, and the food we consume has emerged as a serious environmental concern.
Microplastics are broadly classified into primary microplastics – intentionally produced microplastics such as those found in cosmetics – and secondary microplastics – resulting from the decomposition of larger plastic materials.
Polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene (PE) are among the most commonly used plastics/microplastics in various applications such as making plastic bottles, disposable cutlery, bags, piping, etc.
These conventional plastics are non-biodegradable and remain in the environment for a long time after their improper disposal. These plastics degrade into smaller particles through physical, chemical, or biological processes and persist in the environment due to their slow degradation rate.
Notably, plastic production has increased significantly during the past few decades, with annual output exceeding 400 million tons. It is estimated to reach more than 1 billion tons by 2060.
Microplastics are now ubiquitous and have been found even in remote uninhabited areas. Its widespread presence exposes all ecosystems – terrestrial as well as aquatic – and adversely affects plants, animals, and humans. Microplastics also act as carriers of other environmental pollutants such as heavy metals, persistent organic pollutants, and various toxic additives like plasticisers and stabilisers used during their manufacturing.
The human body is exposed to microplastics through inhalation, ingestion of contaminated food and water, and dermal contact. Drinking water, and everyday food items such as salts, crop plants, and fishery products have been found to contain microplastics.
Once inside the body, these particles can accumulate in various organs and enter the circulatory system, potentially causing harmful health effects. Microplastics have been found in biological fluids and organs such as semen, breast milk, urine, arteries, brain, liver, lung, heart, and placenta.
Various in vitro studies on different cell lines and in vivo studies on animals (rats, mice, zebrafish) and humans have demonstrated the toxicity of microplastics. It can lead to gut dysfunction, respiratory issues, kidney and liver damage, reproductive and developmental problems, neurological disorders, and cardiovascular diseases (CVDs).
According to the World Health Organization (WHO), CVDs are one of the most prevalent non-communicable diseases, accounting for around 27 per cent of total deaths in India in 2016. CVDs comprise various disorders of the heart and blood vessels and include diseases such as hypertension, stroke, myocardial infarction (commonly known as heart attacks), and congenital heart disease.
Heart attack, caused by the disruption of blood flow to the heart muscles, is one of the leading causes of mortality worldwide. These diseases not only cause significant mortality and morbidity but also result in high out-of-pocket medical expenses, loss of employment, mental health issues, and financial distress.
Hence, studying the toxicity of microplastics on cardiovascular health is crucial. The detection of microplastics in the human body can help protect vulnerable patients (high-risk populations), which will help reduce mortality and alleviate healthcare costs for both citizens and the government.
To date, there have been no studies in India on the cardiotoxicity of microplastics in humans. However, recent studies conducted globally have indicated a possible link between microplastics and the severity of CVDs. Microplastics have been shown to cause cardiotoxicity, which refers to damage to the heart muscle or its function, leading to complications such as abnormal heart rhythms (arrhythmias), heart failure, and structural damage to heart tissue.
Microplastics of varying shapes, sizes, and quantities have been detected in various cardiac tissues (including the pericardium, epicardial adipose tissue, myocardium, left atrial appendage, and pericardial adipose tissue) and in arteries (such as the coronary, cerebral, carotid, and aorta). Types of plastics identified include PVC, PET, PE, and PP, the most commonly used microplastics.
Microplastics have also been associated with adverse biological effects, including oxidative stress and inflammation, which can contribute to the development of atherosclerosis. Atherosclerosis is a condition in which plaque – composed of cholesterol, fatty substances, and calcium – accumulates inside the arteries, and leads to the narrowing of the arterial walls and disrupting blood flow to the heart muscle.
If the plaque ruptures, it can lead to the formation of thrombus (blood clot), which may block the artery entirely, disrupt blood flow, and subsequently cause cardiac cell injury and death – a condition commonly known as a heart attack (myocardial infarction).
Studies have shown that microplastic concentrations are higher in cardiac patients compared to control groups (non-cardiac patients). The presence of microplastics in the arteries has been linked to an increased risk of major adverse clinical outcomes, including death, heart attacks, heart failure, reduced cardiac function, and stroke during follow-up periods. Additionally, the severity of ischemic stroke has been found to be correlated with microplastic concentration.
However, the lack of suitable representative samples limits the generalisation of existing research findings to the Indian population. Most studies conducted so far have also used small sample sizes. A definitive cause-and-effect (causal) relationship between microplastics and cardiovascular diseases has yet to be established. Microplastics can merely be bystanders, as confounding variables – such as exposure to other environmental pollutants and comorbidities like diabetes and other diseases – can increase the severity of CVDs.
Therefore, future studies need to focus on understanding the cardiotoxicity of microplastics in India by conducting cohort studies across populations with varying levels of exposure to microplastic concentration. Such studies would be essential to establishing a causal relationship in the Indian context.
In 2022, the United Nations Environment Assembly passed a resolution to form an Intergovernmental Negotiating Committee (INC) tasked with developing a legally binding treaty to address plastic pollution. But the consensus has yet to be reached.
Now the upcoming INC-5.2 meeting scheduled for August 2025 offers some hope that a Global Plastic Treaty will be agreed upon – one that takes into account the concerns of stakeholders and advances global efforts to curb the menace of plastic pollution.
In the case of India, the government has taken practical steps to reduce the misuse of plastics, such as banning single-use plastics effectively from July 1, 2022. Implementing the 3Rs – reduce, recycle, reuse – of waste management will significantly help reduce plastic pollution. In addition, encouraging the use of environment-friendly biodegradable bioplastics such as polyhydroxyalkanoates can help. Moreover, increasing public awareness about the toxic effects of plastics and microplastics is vital in reducing their usage and associated health risks.
What are microplastics, and what are the health risks associated with it?
What steps has the government taken to mitigate plastic pollution and its health effects?
How can the principles of the 3Rs (Reduce, Reuse, Recycle) be effectively implemented in India to combat plastic waste?
What is the role of the United Nations Environment Assembly and the Intergovernmental Negotiating Committee (INC) in addressing global plastic pollution?
How could a Global Plastic Treaty contribute to reducing microplastic exposure and its health implications?
(Ghanshyam Kumar has worked as a Research Fellow at AIIMS Rishikesh and Dr. Bhanu Duggal is Professor and Head of the Department of Cardiology at AIIMS Rishikesh.)
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