This week the World Health Organization (WHO) released new guidelines recommending people switch the regular salt they use at home for substitutes containing less sodium.

But what exactly are these salt alternatives? And why is the WHO recommending this? Let’s take a look.

A new solution to an old problem

Advice to eat less salt (sodium chloride) is not new. It has been part of international and Australian guidelines for decades. This is because evidence clearly shows the sodium in salt can harm our health when we eat too much of it.

Excess sodium increases the risk of high blood pressure, which affects millions of Australians (around one in three adults). High blood pressure (hypertension) in turn increases the risk of heart disease, stroke and kidney disease, among other conditions.

The WHO estimates 1.9 million deaths globally each year can be attributed to eating too much salt.

The WHO recommends consuming no more than 2g of sodium daily. However people eat on average more than double this, around 4.3g a day.

In 2013, WHO member states committed to reducing population sodium intake by 30% by 2025. But cutting salt intake has proved very hard. Most countries, including Australia, will not meet the WHO’s goal for reducing sodium intake by 2025. The WHO has since set the same target for 2030.

The difficulty is that eating less salt means accepting a less salty taste. It also requires changes to established ways of preparing food. This has proved too much to ask of people making food at home, and too much for the food industry.

Enter potassium-enriched salt

The main lower-sodium salt substitute is called potassium-enriched salt. This is salt where some of the sodium chloride has been replaced with potassium chloride.

Potassium is an essential mineral, playing a key role in all the body’s functions. The high potassium content of fresh fruit and vegetables is one of the main reasons they’re so good for you. While people are eating more sodium than they should, many don’t get enough potassium.

The WHO recommends a daily potassium intake of 3.5g, but on the whole, people in most countries consume significantly less than this.

Potassium-enriched salt benefits our health by cutting the amount of sodium we consume, and increasing the amount of potassium in our diets. Both help to lower blood pressure.

Switching regular salt for potassium-enriched salt has been shown to reduce the risk of heart disease, stroke and premature death in large trials around the world.

Modelling studies have projected that population-wide switches to potassium-enriched salt use would prevent hundreds of thousands of deaths from cardiovascular disease (such as heart attack and stroke) each year in China and India alone.

The key advantage of switching rather than cutting salt intake is that potassium-enriched salt can be used as a direct one-for-one swap for regular salt. It looks the same, works for seasoning and in recipes, and most people don’t notice any important difference in taste.

In the largest trial of potassium-enriched salt to date, more than 90% of people were still using the product after five years.

Making the switch: some challenges

If fully implemented, this could be one of the most consequential pieces of advice the WHO has ever provided.

Millions of strokes and heart attacks could be prevented worldwide each year with a simple switch to the way we prepare foods. But there are some obstacles to overcome before we get to this point.

First, it will be important to balance the benefits and the risks. For example, people with advanced kidney disease don’t handle potassium well and so these products are not suitable for them. This is only a small proportion of the population, but we need to ensure potassium-enriched salt products are labelled with appropriate warnings.

A key challenge will be making potassium-enriched salt more affordable and accessible. Potassium chloride is more expensive to produce than sodium chloride, and at present, potassium-enriched salt is mostly sold as a niche health product at a premium price.

If you’re looking for it, salt substitutes may also be called low-sodium salt, potassium salt, heart salt, mineral salt, or sodium-reduced salt.

A review published in 2021 found low sodium salts were marketed in only 47 countries, mostly high-income ones. Prices ranged from the same as regular salt to almost 15 times higher.

An expanded supply chain that produces much more food-grade potassium chloride will be needed to enable wider availability of the product. And we’ll need to see potassium-enriched salt on the shelves next to regular salt so it’s easy for people to find.

In countries like Australia, about 80% of the salt we eat comes from processed foods. The WHO guideline falls short by not explicitly prioritising a switch for the salt used in food manufacturing.

Stakeholders working with government to encourage food industry uptake will be essential for maximising the health benefits.

Xiaoyue (Luna) Xu, Scientia Lecturer, School of Population Health, UNSW Sydney and Bruce Neal, Executive Director, George Institute Australia, George Institute for Global Health

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

Mark Patrick Taylor, Macquarie University and Scott P. Wilson, Macquarie University

A recent study published in the prestigious New England Journal of Medicine has linked microplastics with risk to human health.

The study involved patients in Italy who had a condition called carotid artery plaque, where plaque builds up in arteries, potentially blocking blood flow. The researchers analysed plaque specimens from these patients.

They found those with carotid artery plaque who had microplastics and nanoplastics in their plaque had a higher risk of heart attack, stroke, or death (compared with carotid artery plaque patients who didn’t have any micro- or nanoplastics detected in their plaque specimens).

Importantly, the researchers didn’t find the micro- and nanoplastics caused the higher risk, only that it was correlated with it.

So, what are we to make of the new findings? And how does it fit with the broader evidence about microplastics in our environment and our bodies?

What are microplastics?

Microplastics are plastic particles less than five millimetres across. Nanoplastics are less than one micron in size (1,000 microns is equal to one millimetre). The precise size classifications are still a matter of debate.

Microplastics and nanoplastics are created when everyday products – including clothes, food and beverage packaging, home furnishings, plastic bags, toys and toiletries – degrade. Many personal care products contain microsplastics in the form of microbeads.

Plastic is also used widely in agriculture, and can degrade over time into microplastics and nanoplastics.

These particles are made up of common polymers such as polyethylene, polypropylene, polystyrene and polyvinyl chloride. The constituent chemical of polyvinyl chloride, vinyl chloride, is considered carcinogenic by the US Environmental Protection Agency.

Of course, the actual risk of harm depends on your level of exposure. As toxicologists are fond of saying, it’s the dose that makes the poison, so we need to be careful to not over-interpret emerging research.

A closer look at the study

This new study in the New England Journal of Medicine was a small cohort, initially comprising 304 patients. But only 257 completed the follow-up part of the study 34 months later.

The study had a number of limitations. The first is the findings related only to asymptomatic patients undergoing carotid endarterectomy (a procedure to remove carotid artery plaque). This means the findings might not be applicable to the wider population.

The authors also point out that while exposure to microplastics and nanoplastics has been likely increasing in recent decades, heart disease rates have been falling.

That said, the fact so many people in the study had detectable levels of microplastics in their body is notable. The researchers found detectable levels of polyethylene and polyvinyl chloride (two types of plastic) in excised carotid plaque from 58% and 12% of patients, respectively.

These patients were more likely to be younger men with diabetes or heart disease and a history of smoking. There was no substantive difference in where the patients lived.

Inflammation markers in plaque samples were more elevated in patients with detectable levels of microplastics and nanoplastics versus those without.

And, then there’s the headline finding: patients with microplastics and nanoplastics in their plaque had a higher risk of having what doctors call “a primary end point event” (non-fatal heart attack, non-fatal stroke, or death from any cause) than those who did not present with microplastics and nanoplastics in their plaque.

The authors of the study note their results “do not prove causality”.

However, it would be remiss not to be cautious. The history of environmental health is replete with examples of what were initially considered suspect chemicals that avoided proper regulation because of what the US National Research Council refers to as the “untested-chemical assumption”. This assumption arises where there is an absence of research demonstrating adverse effects, which obviates the requirement for regulatory action.

In general, more research is required to find out whether or not microplastics cause harm to human health. Until this evidence exists, we should adopt the precautionary principle; absence of evidence should not be taken as evidence of absence.

Global and local action

Exposure to microplastics in our home, work and outdoor environments is inevitable. Governments across the globe have started to acknowledge we must intervene.

The Global Plastics Treaty will be enacted by 175 nations from 2025. The treaty is designed, among other things, to limit microplastic exposure globally. Burdens are greatest especially in children and especially those in low-middle income nations.

In Australia, legislation ending single use plastics will help. So too will the increased rollout of container deposit schemes that include plastic bottles.

Microplastics pollution is an area that requires a collaborative approach between researchers, civil societies, industry and government. We believe the formation of a “microplastics national council” would help formulate and co-ordinate strategies to tackle this issue.

Little things matter. Small actions by individuals can also translate to significant overall environmental and human health benefits.

Choosing natural materials, fabrics, and utensils not made of plastic and disposing of waste thoughtfully and appropriately – including recycling wherever possible – is helpful.

Mark Patrick Taylor, Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie University and Scott P. Wilson, Research Director, Australian Microplastic Assessment Project (AUSMAP); Honorary Senior Research Fellow, School of Natural Sciences, Macquarie University

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