Plastic Inside Us

1. Small enough to travel

Microplastics are generally described as plastic particles smaller than 5 mm. Nanoplastics are smaller still, often defined as below 1 micrometre, although definitions differ. A visible fragment, a fine fibre and a nanoscale particle should not be treated as biologically interchangeable. [1]

Some particles are deliberately manufactured small. Others arise through wear, shedding or the breakdown of larger objects. Synthetic clothing, tyres, lost industrial pellets and discarded plastic are recognised sources. A bag that disappears from sight has not necessarily disappeared from the environment. [2]

Food, water and inhaled dust provide routes of exposure. Exposure does not mean every particle is absorbed or stays in the body. Size, shape, polymer (the material making up the plastic), dose and route matter. WHO's 2022 assessment identified substantial gaps in the evidence; it reviewed studies available through December 2021, so it must be read alongside newer research. [1]

2. From the environment into us

A 2022 study reported measurable plastic polymers in blood from a small group of donors. It was an important demonstration of exposure, not a diagnostic test for illness. [3]

In 2025, researchers reported micro- and nanoplastics in postmortem brain, liver and kidney tissue, with higher concentrations in brains from people with a documented dementia diagnosis. The finding attracted headlines about dementia. But detecting material in a diseased brain cannot establish that the material caused the disease; disease itself may alter barriers, clearance or tissue composition. The paper has since carried a published author correction, and scientific correspondence has raised methodological questions about measuring plastics in brain tissue, to which the authors have replied. [4] [5] [6] [7]

These studies deserve attention and replication. They also require good contamination controls: plastic is common in laboratories, collection equipment and the surrounding air. Methods differ in the particle sizes they detect and in whether they report counts or polymer mass. Numbers from different studies cannot simply be added together as a personal lifetime dose.

3. The artery study that sharpened the question

The most compelling clinical hook remains the 2024 New England Journal of Medicine study of patients undergoing surgery for carotid artery narrowing. Among 257 patients who completed follow-up, polyethylene was detected in plaque from 150 (58.4%). Follow-up averaged about 34 months. [8]

The combined outcome of heart attack, stroke or death from any cause occurred in 30 of 150 patients with detected micro- or nanoplastics (20.0%), compared with 8 of 107 without detected particles (7.5%). The adjusted hazard ratio was 4.53, with a 95% confidence interval of 2.00–10.27. The wide interval shows uncertainty about the size of the association. [8]

This was an observational study of people who already had established vascular disease. Differences between the groups that statistical adjustment may not fully remove, and possible sample contamination, limit interpretation. These figures are not population risks: the result does not mean drinking bottled water makes anyone's heart-attack risk four times greater. It supplies a serious question for further study. [8]

Back in clinic, this is where the patient from the opening would press me. A plaque study cannot tell me whether the plastic in their blood matters, or whether anything I could do about it would change their outcome. What it does tell me is that the question deserves better research.

4. Plausible harm is not yet a clinical verdict

Experimental research provides reasons to investigate inflammation, oxidative stress and changes in immune function. Plastics may also contain additives or carry other chemicals. But particle effects and chemical effects are different questions, and laboratory doses do not necessarily represent ordinary human exposure. [1] [2]

Headlines now connect microplastics with infertility, dementia, cancer and metabolic disease. The strength of the evidence varies by outcome. A finding in tissue, an animal experiment and a prospective human study answer different questions, and we should not merge them into a single list of diseases supposedly caused by plastic.

The US FDA states that current evidence does not demonstrate that the levels of micro- and nanoplastics detected in foods pose a risk to human health. That is an assessment of the available evidence, not proof of lifetime harmlessness. Better measurements and longer human studies remain necessary. [9]

5. Malaysia is already part of the story

This concern did not begin with the latest headline. In a 2020 Malaysian Journal of Medical Sciences editorial, Ma, Ibrahim and Lee connected microplastic exposure with Malaysia's single-use-plastics roadmap. They discussed potential hazards while acknowledging that much of the evidence came from animals and that human studies were needed. [10]

A study of eight major bottled-water brands available in Malaysia reported microplastics at 8–22 particles per litre, mainly PET and polypropylene, consistent with packaging and bottle caps as sources. The dominant particle size was 100–300 µm, far larger than the sub-micron particles described in the tissue studies above, so the bottled-water finding describes exposure rather than what reaches the bloodstream. The estimated intake the authors calculated was low, and the results describe the brands and methods studied, not every brand and batch sold today. [11]

A 2026 descriptive study of semen from 115 Malaysian men aged 18–45 detected microplastics in all samples, at 0.2–3.3 particles per mL, with sizes of 4–27 micrometres. Polypropylene and PET were the predominant polymers. It characterised the particles and surface-associated elements (qualitative surface co-occurrence, not confirmed adsorption) but did not assess reproductive health outcomes. It therefore cannot establish a link with infertility, and the participants should not be treated as nationally representative. [12]

We have local evidence of exposure. We do not yet have a dependable national estimate of the resulting clinical burden. That distinction matters when the next headline arrives.

6. Should we stop eating seafood?

The bottle is one route; the plate is another, and it is the one Malaysians ask me about most. Finding plastic in a fish is not the same as demonstrating harm from eating it. The edible portion matters. EFSA's 2016 statement highlighted particles in digestive tracts, often removed before fish is eaten, whereas shellfish or small animals eaten whole provide a different exposure. This does not establish that fish flesh is always free of particles, and EFSA noted major gaps in methods and in health-risk assessment. [13]

There is therefore no sound basis for a blanket recommendation to stop eating seafood solely because microplastics have been detected. Follow established food-safety advice and any local contamination advisories.

In The Star's 3 October 2026 report, Fisheries Department director-general Datuk Adnan Hussain said national studies found microplastics in the gastrointestinal tracts of 93.3% of Indian mackerel examined, and, at low concentrations, in the edible muscle of 28.89%. He said the department considers the risk from seafood low, cited FAO risk assessments, and did not advise the public to avoid seafood, while stressing that the problem must be tackled at source. So particles in the flesh are not zero, which is why the exposure is described as minimised rather than absent. These are the department's figures and position as reported by the newspaper, not a quantified lifetime risk assessment, and the underlying studies are not cited in the report. [14]

7. What should the doctor say?

For someone who is well but worried, I would not recommend routine microplastic testing. Research measurements do not yet offer an established harmful threshold or a validated treatment target. A number without a reliable interpretation can create anxiety without improving care.

Part of the reason is that no clinical test exists. The published studies used research-laboratory methods on samples that were digested and analysed. Pyrolysis gas chromatography–mass spectrometry, which measures the mass of each polymer, was used on blood, carotid plaque and brain tissue; electron microscopy was used to see the particles; and Raman microspectroscopy identified polymers in semen. [3] [4] [8] [12] Even the blood method measured only particles of 700 nm or larger, so smaller particles would be missed. [3] Methods differ between studies, contamination is a constant risk, and no result comes with a validated reference range.

Nor is there an established treatment shown to remove microplastics from the body and improve clinical outcomes. A detox claim should have to demonstrate both removal and meaningful benefit, with acceptable risks. A testimonial or a change in an experimental laboratory result is insufficient.

Symptoms still deserve ordinary clinical assessment. Cardiovascular prevention, investigation of infertility and evaluation of cognitive decline should follow the evidence for those conditions. Microplastics research does not replace it. This is my reading of the evidence gaps, not a dedicated Malaysian microplastics guideline. [1] [9]

8. What we know and what we do not

These gaps justify research and proportionate prevention. They do not justify a detox prescription.

9. What we can reasonably change at home

Use containers as intended. The FDA advises using cookware made for microwave use and warns that some plastic containers can be melted by the heat of the food inside, so follow the manufacturer's directions and do not assume a takeaway tub is suitable for reheating. [15]

Where safe drinking water is available, a durable refillable bottle can reduce disposable packaging. Buy fewer unnecessary single-use items, reuse suitable products, and follow local recycling rules. Keeping clothes in use longer also reduces discarded clothing, although it does not by itself demonstrate less fibre shedding during washing.

Synthetic fabrics can shed fibres; filtration may intercept some during washing, but performance varies. Captured lint belongs in collected waste, not down the drain. Tyres also shed during use, so transport choices matter. These measures address waste and environmental release; their effect on an individual's internal exposure is harder to quantify. [2] [16]

Do not compromise safe drinking water or food hygiene in pursuit of zero plastic. The benefits of clean water and safe food are far better established than the benefits of any microplastic-avoidance routine.

10. Stop the particles before they spread

Households cannot redesign tyres, secure industrial pellet transport or operate sewage works. Prevention needs institutions as well as individual choices.

Industry can develop textiles that shed less, improve tyre design and prevent pellet spills during manufacture and transport. Authorities can improve waste collection and intercept road runoff. Wastewater treatment can capture particles, but capture is not destruction: sludge and collected residues still need safe management. [2] [16]

Beach and river clean-ups remain useful because removing larger litter prevents some future fragmentation. They cannot retrieve all the fine particles already dispersed through soil, water and air. The strongest approach combines prevention, capture and responsible disposal. [2]

11. Malaysia: from roadmaps to results

Policy documents set targets; they are not results. That distinction runs through everything below.

Malaysia's Roadmap Towards Zero Single-Use Plastics 2018–2030 promotes reducing disposable plastics and encouraging alternatives. The Malaysia Plastics Sustainability Roadmap 2021–2030 extends the approach across the plastics value chain. Its stated targets include recycling 25% of post-consumer plastic packaging by 2025, 100% recyclability of plastic packaging and 15% average recycled content by 2030. Recyclability is not the same as actual recycling. [17] [18]

The sustainability roadmap proposes extended producer responsibility (EPR), making producers responsible beyond sale and into waste management. The plan envisaged a voluntary phase to 2025 and mandatory packaging EPR from 2026. ERIA's legal-framework overview states that Malaysia has no dedicated EPR legislation, although Section 102 of the Solid Waste and Public Cleansing Management Act 2007 lets the Minister introduce EPR, and that the government was developing a framework to move to a mandatory scheme by 2026. Whether that has now taken legal effect I have not confirmed. [18] [19]

The National Marine Litter Policy and Action Plan 2021–2030 and KPKT's Circular Economy Blueprint for Solid Waste 2025–2035 broaden the response beyond asking shoppers to refuse a bag. These documents establish policy direction and targets, rather than verified achievements or measured reductions in human exposure. [20] [21]

ERIA's Regional Knowledge Centre records early measures such as plastic-bag charges, no-straw-by-default practice and eco-labelling for biodegradable and compostable packaging, excluding oxo- and photo-degradable packaging. Its overview does not establish nationwide compliance. [22]

This direction also has an international history. At the November 2019 UNEP expert-group meeting, Malaysia called for regional cooperation, better capacity and action against improperly declared plastic-waste imports. [23] [24]

The next questions are operational. Are tyre and textile releases being measured? How are pellet losses prevented? What happens to particles captured in treatment sludge? Can water and food measurements be compared between laboratories?

I have not verified a national health-based microplastic limit for drinking water or food, or nationwide routine monitoring covering these sources. That does not mean no relevant programme or standard exists; MOH, NRES, DOE, SPAN and wastewater operators would be the appropriate sources for clarification. For Malaysia, I would favour comparable monitoring methods, public reporting, source-specific prevention and research linking exposure with health outcomes.

12. The international response is moving upstream

The EU has a target to reduce microplastic releases by 30% by 2030. Its REACH restriction, adopted in 2023, addresses microplastics intentionally added to products, while Regulation (EU) 2025/2365, adopted in November 2025, addresses plastic-pellet losses and applies to operators handling five tonnes or more of pellets a year. Adoption of rules should be distinguished from their application dates and from evidence of achieved reductions. [25]

The UN process aims to develop a legally binding instrument covering the full plastics life cycle, including production, design and disposal. It remains a negotiation: UNEP records a February 2026 session devoted to organisational matters, without substantive negotiations. A treaty under negotiation should not be described as an agreement already delivering results. [26]

The policy lesson is useful even before a final treaty: waste disposal alone cannot solve a problem continually generated during production and everyday use.

13. Ask the earlier question

Plastic has earned its place in medicine and daily life. The task is to reduce unnecessary use and environmental leakage while preserving useful applications. We can act on avoidable pollution without pretending that every clinical uncertainty has been settled.

The question is no longer whether plastic reaches us. It does. The harder question is what happens after it gets there.

But perhaps we should ask an earlier question: how much of it needed to get there in the first place?