Halt your salt: The latest research on salt’s link to heart, cancer and brain diseases – Noted

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Of course, salt isnt the only dietary factor that influences our heart health. There are a range of dietary approaches that can be heart healthy. Its not just one formula, says Monro. But there is one consistent theme, he adds, and thats eating more vegetables, fruit and intact whole grains while cutting down on processed foods.

While we work with processed food companies to reduce sugar and salt levels, we also have these important dietary messages about cutting down on processed foods and actually choosing foods as close to how theyre found in nature as possible.

The most important thing is to look at your total diet, he says, rather than fixating on one or two nutrients. Although choosing a lower-sodium bread and breakfast cereal is a great starting point, its also important to eat more fruit, vegetables and whole grains and minimise processed foods.

What that diet consists of can be based on personal preferences and circumstances wholefoods can be relatively expensive. But whether its a Mediterranean style of eating, a Nordic diet, or following the Dash (Dietary Approaches to Stop Hypertension) diet, all have been shown to reduce blood pressure unsurprisingly, since all of these dietary patterns are rich in fruit, vegetables, whole grains, legumes, seeds, nuts, fish and dairy and low in meat, sweets and alcohol. Add to that a lifestyle that includes regular activity and its a winning formula for cardiovascular health.

McLean says about 10% of our intake is from sodium naturally in foods, and theres some in water as well, which is enough to keep us going. All the rest of the sodium were consuming through processed foods is unneeded. Its almost impossible to have a low sodium intake in our current food environment.

As an alternative to adding salt for flavour in home cooking, herbs and spices can be successfully used, with taste buds quickly adapting. In a US trial in 2014, participants reduced their average sodium intake by 1000mg a day.

Its not impossible to change an entire nations high-salt habits. In the UK, a major salt-reduction programme that began in 2003, pushed through under threat of regulation by the Department of Health, resulted in substantially less sodium in the food supply. Over seven years, there was a 15% decrease in the average salt intake of the population at a relatively small cost, with potentially major healthcare savings and reductions in disease and premature death.

Says McLean: We would love the Government to do a bit more and set some targets for the food industry. The Heart Foundation is doing a really good job within its scope. But the places, the companies, around the world that have seriously reduced the salt intake of their population have had some degree of regulation and a much more active government involvement in sodium reduction.

Only 2% of NZ shoppers were able to correctly identify the amount of salt in a can of beans.

A quick check of the nutrition information panel on food packages reveals there is no detail on salt content, only sodium. Salt is, in fact, sodium chloride and sodium makes up just under 40% of its content.

However, a 2006 New Zealand study found more than 58% of shoppers believed sodium and salt were interchangeable, and that the sodium figure given on the nutrition information panel represented the salt content of the food.

Consumers need to multiply the amount of sodium listed in the nutrition information panel by 2.5 to work out how much salt a product contains.

This isnt common knowledge, with the same research team finding that only 2% of New Zealand shoppers were able to correctly identify the amount of salt in a can of beans based on the nutrition information panel.

The Ministry of Health recommends an upper daily limit for sodium of 2.4g, equivalent to about 6g of salt. To optimise diets and lower chronic disease risk, however, it suggests lowering sodium intake further to 1.6g a day, or 4g of salt.

And the World Health Organisation recommends a daily sodium intake of less than 2g for adults, equivalent to 5g (just under a teaspoon) of salt from all sources water, whole foods and processed foods.

Some people who consume too much salt are more at risk of developing hypertension than others.

In recent years, there has been much talk about how genetics alters disease risk, including our risk of high blood pressure from a high-salt diet.

It seems highly likely that there is a genetic predisposition to being more salt sensitive, says Dr Rachael McLean of the University of Otago. And some people seem to have a greater blood pressure reaction to high-salt diets than others. But we dont have a good way of telling who those people are on an individual level.

In 2010, Chinese researchers conducted a large family-based dietary trial in rural North China. What they did was give people high- and low-salt diets and identify individuals who seemed to have a greater reaction in terms of raised blood pressure to a high-salt diet, says McLean. The Genetic Epidemiology Network of Salt Sensitivity (GenSalt) study found that 39% of Chinese adults were sodium sensitive: their blood pressure was raised more on a high-salt diet than that of other individuals. It also revealed that sodium sensitivity was more common in women, older adults, individuals with metabolic syndrome and those who typically had higher blood pressure.

In some ways, developing hypertension is a good indication that you may be more salt sensitive than other people, says McLean. For instance, in randomised controlled trials there is clear evidence that lowering salt intake has a bigger effect on the blood pressure of people with pre-existing hypertension than those with normal blood pressure. By reviewing genetic variations in the more sodium-sensitive individuals, the Chinese research team compiled a list of candidate genes that may play a factor in determining sodium sensitivity.

A number of different genes may have a role, says McLean. There are also many potential mechanisms by which sodium sensitivity might occur, whether the effect is on the kidneys, the lining of the blood vessels or a combination of both.

There certainly doesnt seem to be one individual gene with one individual mechanism that dominates things.

Were a long way from understanding how genes are involved in salt sensitivity and were even further from being able to identify individuals that are more salt sensitive than others, either on a genetic or a clinical basis. Until we know a bit more about salt sensitivity, it makes sense for everybody to reduce their salt intake.

This article was first published in the January 18, 2020 issue of the New Zealand Listener.

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Halt your salt: The latest research on salt's link to heart, cancer and brain diseases - Noted