The majority conception we have of our planet as an inexhaustible source of raw materials has made production systems oriented towards a use and throw . If there is no limit, why reduce consumption speed. Fashion brands that sell ephemeral quality clothes are increasingly common at very low prices with the aim of taking new campaigns almost every month. Or something as usual as buying plastic packaged foods unnecessary (at the cusp of the absurd package to the vacuum peeled fruits ) to end up generating a mountain of daily waste, while the planet cannot assume this plug of fossil reserves, on the one hand , and plastic accumulation for another.

A recent report by the United Nations Organization entitled " Our planet drowns in a sea of ​​plastic " (you can read it in detail in this link ) about the plastic problem contains some alarming conclusions. These are the main ones and that show shocking data:

A million plastic bottles are bought worldwide , while up to 5 billion plastic bags per year are used.

· Half of all plastic produced in the world is designed to be discarded after being used only once.

· Today, we produce around 400 million tons of plastic waste every year.

· Of the 7,000 million tons of plastic waste generated worldwide so far, less than 10% has been recycled .

· Cigarette butts are the most common type of plastic waste found in the environment. Next place are food wrappers, plastic bottles, bottles covers, supermarket bags and straws.

· It is estimated that to date there are between 75 and 199 million tons of plastic in our oceans .

Plastic as a consumer product has characteristics (mainly its durability and resistance to degradation) that make their decomposition in nature almost impossible. This causes that when it is thrown, the waves of the sea, abrasion, ultraviolet radiation and photooxidation in combination with bacteria, degrade plastic fragments into tiny size particles. ¹ The result of this whole process is what we know as microplastics (defined as particles of less than 5 mm) and nanoplastic (particles of less than 1000 nanometers).

Invasion of microplastics in nature ... and in our body

More than two decades ago Marino Biologist Richard Thompson posted an article entitled Science Where is the entire plastic? ² It was one of the first investigations to show that our oceans were becoming a plastic landfill. The figures were bleak. They found plastic remains between the plankton and the seabed since the 1960s, but the amount increased proportionally to world plastic production (Figure 1). The article concluded in this way: “ Given the rapid increase in plastic production, its longevity and its disposable nature, this pollution is probable. It remains to be demonstrated if toxic substances can move from plastics to the food chain . ”

Figure 1. Increased microscopic plastic concentration in marine sediment samples and plankton from 1960 to 1990. Adapted figure of Thomson et al. Science . ²

We currently know that almost 99% of that plastic that ends at sea is deposited in the seabed, finding 10,000 times more plastic in the depths than in the most superficial waters. ^3,4 In addition, as our planet is connected, we have microplastic records ranging from the top of Everest to the Arctic. ⁵

While for many this problem may seem invisible and harmless to our health (since if it does not harm us directly, it seems not to exist), such as the murderer in the scene of a crime, microplastics are beginning to leave a trace that links them with multiple diseases, some of them mortal. To the question that was asked of whether this plastic had passed to the food chain, it seems that the answer is yes.

If the planet accumulates plastic, the animals that inhabit it also. In fact, and here the most direct consequences for people begin to be seen, microplastics have been found in different human tissues such as lungs, liver, urine or blood. ⁶ If this should already scare us, the trace of microplastics reaches breast milk and placenta. For example, a recent study that analyzed 34 women's breast milk samples found microplastic pollution in 26 of them. ⁷ The presence of these oil derivatives, with unpredictable consequences for the baby's health, has been discovered even in the deepest link between a mother and the fetus: the placenta. In 2021 the presence of microplastics was first described in human placenta samples collected from six patients who had given birth . ⁸

What can cause in health the presence of microplastics?

That we are surrounded by plastic we have seen that it is out of any doubt. But can it affect the normal function of the organism? Evidence in in vitro and animals follows that microplastics produce oxidative stress, inflammation and premature death of cells of blood vessels, as well as an altered heart rate, deterioration of cardiac function, myocardial fibrosis and endothelial dysfunction. ⁹

What are these physiological responses translated? A study published in 2022 found that patients with inflammatory intestinal disease ( we published an article in which we talk about the impact of stress on these diseases ) had a significantly greater amount of microplastics in their feces than those who did not have the disease. ¹⁰ When analyzing the characteristics and concentration of microplastics in the feces of patients with inflammatory intestinal disease and in healthy individuals, it was observed that the concentration was remarkably greater in those diagnosed with the disease (41.8 elements/g dm vs , 0 elements/g dm). In addition, the severity of the disease was correlated with a greater concentration of plastics in feces (Figure 2).

Figure 2 . People with inflammatory intestinal disease have a greater presence of microplastics. In addition, there is a positive correlation between the concentration and severity of the disease. Adapted from Yan et al. ¹⁰

More recently, the prestigious magazine The New England Journal of Medicine has published an article in which it shows the possible consequences of microplastics in cardiovascular health. ¹¹ The results are alarming. In a multicentric study, researchers analyzed 257 patients who were going to submit to surgical intervention (carotid endarterectomy) to treat the obstruction of blood flow in the carotid. The carotid plate samples that were removed were analyzed to detect the presence of microplastics. These patients had a monitoring of almost three years to evaluate the prevalence of cardiovascular events.

Figure 3 . Aseroma plate analysis. Figure A shows images of electronic microscopy of non -organic particles detected within macrophages (arrows). In Figure B, obtained with another microscopy technique, macrophages scattered on the plate and small particles with similar characteristics (red boxes) are shown. Adapted figure of Ivory et al. ¹¹

What were the results? The patients who were found microplastics in the carotid plates had 4.5 times more likely to experience a heart attack, a stroke or die for any cause compared to those whose plaque was free of microplastics (Figure 4).

Figure 4 . Patoplastic patients in the carotid plates had a higher risk of stroke, myocardial or death infarctions for any cause. The results adjusted to age, sex, body mass index, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, or risk factors such as having diabetes or hypertension. Adapted figure of Ivory et al. ¹¹

It should be noted that these results do not demonstrate causality between the presence of microplastics and the greatest risk of cardiovascular or inflammatory diseases. However, growing evidence suggests that microplastics are not harmless to health and that the problem only aggravates, since its production does not stop growing.

Conclusions 

As a society we are facing multiple problems that derive from an erroneous conception of our planet: infinite growth in a finite planet is impossible. In addition, to the scarcity of drinking water, virgin fossil products or key raw materials for technological production, it must be added that everything that is undone, does not disappear as if nothing, leaves a mark. Health problems derived from the accumulation of microplastics are emerging and their consequences seem to be serious: they increase the risk of cardiovascular events and mortality. The path that we have left, beyond being able to find potential treatments, lies in a change in the consumption paradigm that is based on the 3R: reduce, reuse and recycle.

References:

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