Plastic is in our clothes, cars, mobile phones, water bottles and food containers. But recent research adds to growing concerns about the impact of tiny plastic fragments on our health.

A study from the United States has, for the first time, found microplastics in human brains. The study, which has yet to be independently verified by other scientists, has been described in the media as scary, shocking and alarming.

But what exactly are microplastics? What do they mean for our health? Should we be concerned?

What are microplastics? Can you see them?

We often consider plastic items to be indestructible. But plastic breaks down into smaller particles. Definitions vary but generally microplastics are smaller than five millimetres.

This makes some too small to be seen with the naked eye. So, many of the images the media uses to illustrate articles about microplastics are misleading, as some show much larger, clearly visible pieces.

Microplastics have been reported in many sources of drinking water and everyday food items. This means we are constantly exposed to them in our diet.

Such widespread, chronic (long-term) exposure makes this a serious concern for human health. While research investigating the potential risk microplastics pose to our health is limited, it is growing.

How about this latest study?

The study looked at concentrations of microplastics in 51 samples from men and women set aside from routine autopsies in Albuquerque, New Mexico. Samples were from the liver, kidney and brain.

These tiny particles are difficult to study due to their size, even with a high-powered microscope. So rather than trying to see them, researchers are beginning to use complex instruments that identify the chemical composition of microplastics in a sample. This is the technique used in this study.

The researchers were surprised to find up to 30 times more microplastics in brain samples than in the liver and kidney.

They hypothesised this could be due to high blood flow to the brain (carrying plastic particles with it). Alternatively, the liver and kidneys might be better suited to dealing with external toxins and particles. We also know the brain does not undergo the same amount of cellular renewal as other organs in the body, which could make the plastics linger here.

The researchers also found the amount of plastics in brain samples increased by about 50% between 2016 and 2024. This may reflect the rise in environmental plastic pollution and increased human exposure.

The microplastics found in this study were mostly composed of polyethylene. This is the most commonly produced plastic in the world and is used for many everyday products, such as bottle caps and plastic bags.

This is the first time microplastics have been found in human brains, which is important. However, this study is a “pre-print”, so other independent microplastics researchers haven’t yet reviewed or validated the study.

How do microplastics end up in the brain?

Microplastics typically enter the body through contaminated food and water. This can disrupt the gut microbiome (the community of microbes in your gut) and cause inflammation. This leads to effects in the whole body via the immune system and the complex, two-way communication system between the gut and the brain. This so-called gut-brain axis is implicated in many aspects of health and disease.

We can also breathe in airborne microplastics. Once these particles are in the gut or lungs, they can move into the bloodstream and then travel around the body into various organs.

Studies have found microplastics in human faeces, joints, livers, reproductive organs, blood, vessels and hearts.

Microplastics also migrate to the brains of wild fish. In mouse studies, ingested microplastics are absorbed from the gut into the blood and can enter the brain, becoming lodged in other organs along the way.

To get into brain tissue, microplastics must cross the blood-brain-barrier, an intricate layer of cells that is supposed to keep things in the blood from entering the brain.

Although concerning, this is not surprising, as microplastics must cross similar cell barriers to enter the urine, testes and placenta, where they have already been found in humans.

Is this a health concern?

We don’t yet know the effects of microplastics in the human brain. Some laboratory experiments suggest microplastics increase brain inflammation and cell damage, alter gene expression and change brain structure.

Aside from the effects of the microplastic particles themselves, microplastics might also pose risks if they carry environmental toxins or bacteria into and around the body.

Various plastic chemicals could also leach out of the microplastics into the body. These include the famous hormone-disrupting chemicals known as BPAs.

But microplastics and their effects are difficult to study. In addition to their small size, there are so many different types of plastics in the environment. More than 13,000 different chemicals have been identified in plastic products, with more being developed every year.

Microplastics are also weathered by the environment and digestive processes, and this is hard to reproduce in the lab.

A goal of our research is to understand how these factors change the way microplastics behave in the body. We plan to investigate if improving the integrity of the gut barrier through diet or probiotics can prevent the uptake of microplastics from the gut into the bloodstream. This may effectively stop the particles from circulating around the body and lodging into organs.

How do I minimise my exposure?

Microplastics are widespread in the environment, and it’s difficult to avoid exposure. We are just beginning to understand how microplastics can affect our health.

Until we have more scientific evidence, the best thing we can do is reduce our exposure to plastics where we can and produce less plastic waste, so less ends up in the environment.

An easy place to start is to avoid foods and drinks packaged in single-use plastic or reheated in plastic containers. We can also minimise exposure to synthetic fibres in our home and clothing.

Sarah Hellewell, Senior Research Fellow, The Perron Institute for Neurological and Translational Science, and Research Fellow, Faculty of Health Sciences, Curtin University; Anastazja Gorecki, Teaching & Research Scholar, School of Health Sciences, University of Notre Dame Australia, and Charlotte Sofield, PhD Candidate, studying microplastics and gut/brain health, University of Notre Dame Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

If you’re thinking about buying plant-based foods, a trip to the supermarket can leave you bewildered.

There are plant-based burgers, sausages and mince. The fridges are loaded with non-dairy milk, cheese and yoghurt. Then there are the tins of beans and packets of tofu.

But how much is actually healthy?

Our nutritional audit of more than 700 plant-based foods for sale in Australian supermarkets has just been published. We found some products are so high in salt or saturated fat, we’d struggle to call them “healthy”.

We took (several) trips to the supermarket

In 2022, we visited two of each of four major supermarket retailers across Melbourne to collect information on the available range of plant-based alternatives to meat and dairy products.

We took pictures of the products and their nutrition labels.

We then analysed the nutrition information on the packaging of more than 700 of these products. This included 236 meat substitutes, 169 legumes and pulses, 50 baked beans, 157 dairy milk substitutes, 52 cheese substitutes and 40 non-dairy yoghurts.

Plant-based meats were surprisingly salty

We found a wide range of plant-based meats for sale. So, it’s not surprising we found large variations in their nutrition content.

Sodium, found in added salt and which contributes to high blood pressure, was our greatest concern.

The sodium content varied from 1 milligram per 100 grams in products such as tofu, to 2,000mg per 100g in items such as plant-based mince products.

This means we could eat our entire daily recommended sodium intake in just one bowl of plant-based mince.

An audit of 66 plant-based meat products in Australian supermarkets conducted in 2014 found sodium ranged from 316mg in legume-based products to 640mg in tofu products, per 100g. In a 2019 audit of 137 products, the range was up to 1,200mg per 100g.

In other words, the results of our audit seems to show a consistent trend of plant-based meats getting saltier.

What about plant-based milks?

Some 70% of the plant-based milks we audited were fortified with calcium, a nutrient important for bone health.

This is good news as a 2019-2020 audit of 115 plant-based milks from Melbourne and Sydney found only 43% of plant-based milks were fortified with calcium.

Of the fortified milks in our audit, almost three-quarters (73%) contained the recommended amount of calcium – at least 100mg per 100mL.

We also looked at the saturated fat content of plant-based milks.

Coconut-based milks had on average up to six times higher saturated fat content than almond, oat or soy milks.

Previous audits also found coconut-based milks were much higher in saturated fat than all other categories of milks.

A first look at cheese and yoghurt alternatives

Our audit is the first study to identify the range of cheese and yoghurt alternatives available in Australian supermarkets.

Calcium was only labelled on a third of plant-based yoghurts, and only 20% of supermarket options met the recommended 100mg of calcium per 100g.

For plant-based cheeses, most (92%) were not fortified with calcium. Their sodium content varied from 390mg to 1,400mg per 100g, and saturated fat ranged from 0g to 28g per 100g.

So, what should we consider when shopping?

As a general principle, try to choose whole plant foods, such as unprocessed legumes, beans or tofu. These foods are packed with vitamins and minerals. They’re also high in dietary fibre, which is good for your gut health and keeps you fuller for longer.

If opting for a processed plant-based food, here are five tips for choosing a healthier option.

1. Watch the sodium

Plant-based meat alternatives can be high in sodium, so look for products that have around 150-250mg sodium per 100g.

2. Pick canned beans and legumes

Canned chickpeas, lentils and beans can be healthy and low-cost additions to many meals. Where you can, choose canned varieties with no added salt, especially when buying baked beans.

3. Add herbs and spices to your tofu

Tofu can be a great alternative to meat. Check the label and pick the option with the highest calcium content. We found flavoured tofu was higher in salt and sugar content than minimally processed tofu. So it’s best to pick an unflavoured option and add your own flavours with spices and herbs.

4. Check the calcium

When choosing a non-dairy alternative to milk, such as those made from soy, oat, or rice, check it is fortified with calcium. A good alternative to traditional dairy will have at least 100mg of calcium per 100g.

5. Watch for saturated fat

If looking for a lower saturated fat option, almond, soy, rice and oat varieties of milk and yoghurt alternatives have much lower saturated fat content than coconut options. Pick those with less than 3g per 100g.

Laura Marchese, PhD Student at the Institute for Physical Activity and Nutrition, Deakin University and Katherine Livingstone, NHMRC Emerging Leadership Fellow and Senior Research Fellow at the Institute for Physical Activity and Nutrition, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.