A new study published in the New England Journal of Medicine this month has prompted calls in Europe for EU-wide salt legislation.
In the NEJM paper, the authors undertook a computer simulation showing the effects of population-wide reductions in dietary salt intakes among adults aged 35 to 85 years living in the USA.
They claim that: “a reduction in dietary salt of 3g per day would have approximately the same effect on rates of coronary heart disease (CHD) events as a 50% reduction in tobacco use, a 5% reduction in body mass index among obese adults, or the use of statins to treat persons at low or intermediate risk for CHD events.”
The authors go on to say, “a population-wide reduction of salt intake of 3g per day is expected to result in the same reduction in death rates as the use of medical treatment to control hypertension in all persons with this condition”.
With this week being World Salt Awareness Week, the research adds further impetus to the need for people to substantially reduce (in New Zealand, by some 33%) their salt intake.
We asked nutrition experts what the implications are for New Zealanders, and what public health advice they would give, based on this new research.
Amanda Brien, a public health nutritionist with Taranaki District Health Board, comments:
“Salt is the main source of sodium in our diets. Too much sodium is linked to high blood pressure, heart disease and stroke. The Ministry of Health recommends we eat no more than 6.0g salt per day, which is a bit more than one teaspoon. Currently, New Zealanders are having nearly double this amount at 9.0g per day.
“Taking the salt off the dinner table is a good start to reducing your daily intake, but the majority of salt in our diets comes from processed foods. Salt is used as a preservative and flavour in a range of foods such as, takeaways, bread, biscuits, chips, sauces, cheese, meat and pickled vegetables.
“Already some manufacturers are reducing the amount of sodium in their products through initiatives like the National Heart Foundation’s Pick the Tick or by offering low-salt options. Learn to read food labels and look for products with less than 450mg of sodium per 100g. You will be surprised with the differences between brands. For example, cracker biscuits can range from about 200mg to a whopping 1600mg of sodium per 100g!
“Start to lower the amount of salt you use at home in cooking. Taking a little bit out each day adds up over time and helps reduce risk of heart disease. Get creative in the kitchen and use other flavours like lemon, herbs or spices to liven up meals.”
Amy Liu, a registered dietitian and nutrition consultant, comments:
“Processed food provides the majority of our salt intake, contributing up to 85% to total intakes.
“A new U.S. study, published in the New England Journal of Medicine this month, reported that reducing dietary salt by up to 3g per day is projected to reduce the annual number of new cases of CHD by 60,000-120,000; stroke by 32,000-66,000; and myocardial infarction by 54,000-99,000. The study also reports that the annual number of deaths by any cause would be reduced by 44,000-92,000. In addition, $10 -24 billion (USD) in health costs would be saved per year. Even a modest reduction of 1g per day would be more cost effective than using medication to lower blood pressure.
“These results are in alignment with the findings from a randomised controlled feeding trial called DASH (Dietary Approach to Stop Hypertension). Along with reducing salt intake, the DASH eating plan involved consuming foods that were low in total fat, saturated fatty acids and cholesterol and included plenty of fruits, vegetables and low-fat dairy products. Also included were wholegrain products, fish, poultry and nuts.
“My advice to New Zealanders who wish to reduce their blood pressure is to cut down on salty foods and avoid adding salt in cooking and at the table. Also, follow a healthy diet that includes lots of fruits and vegetables, wholegrain cereals, low-fat dairy products, fish, poultry and nuts.”
Mary Rose Spence, a registered dietitian and nutrition consultant, comments:
“We have acknowledged in New Zealand for a number of years that a high salt (sodium) intake is linked to high blood pressure, and this is a risk factor for heart disease and strokes.
“In New Zealand, the daily intake of salt (sodium) for adults is approximately 9g/day.The Heart Foundation in NZ recommends an intake of 6g/day. The Report of the Nutrition Taskforce 1991 put out by the Dept of Health suggested an intake of 7g/day or less by the year 2000. We are still significantly above these targets.
“Most of the sodium consumed (approx 85%) comes from processed and manufactured foods. Only about 15% comes from salt we add from the shaker or in cooking.
“Some New Zealand food companies are already engaged in salt reduction – either through their own initiatives or in collaboration with the Heart Foundation. The Heart Foundations Pick the tick programme aims to reduce levels of salt in commonly eaten foods. In one year 33 tonnes of salt was removed from the food supply by encouraging manufacturers to reduce salt contents so they were eligible for the Heart Tick.
“The foods that typically have high sodium levels are bread, butter, cheese, some breakfast cereals, sauces, take-away foods, canned foods and processed meats. The salt levels of breads are currently being reduced and as a result of this project, up to 150 tonnes of salt will be removed annually from the New Zealand bread supply.
“It is important we have easily understood information, to allow consumers to make informed choices when there is such a vast range of products such as breads and cereals available.
We need to keep encouraging our food manufacturers to gradually reduce the salt content of processed foods and assist our population in identifying salt in products and making informed choices when shopping.”
Namalie Jayasinya, Business Manager of Food Reformulation at the Heart Foundation, comments:
“High salt intake is strongly linked to raised blood pressure, a major risk factor for heart disease. High blood pressure is in fact the leading global risk factor for mortality – outranking tobacco use, physical inactivity, blood cholesterol, obesity and overweight. At least one in seven adults in New Zealand takes medication for high blood pressure.
“New Zealanders’ intake of salt is estimated at around 9g/day. This is 50% higher than the maximum recommended intake of 6g/day. Bread is the main source of sodium in the diet of New Zealanders, contributing 26% of our sodium intake. Other major sources of sodium include processed meat (10%), breakfast cereals (6%) and sauces (6%). Some categories have made a significant effort to reduce salt levels since the survey that collected these statistics.
How should we reduce these salt intakes?
“Increasing consumer awareness of the need to reduce salt intakes, consumers reading food labels, consumers demanding low/er salt options and manufacturers reducing salt in the foods they produce are the most obvious ways to reduce salt intake across the population.
Should we be calling for manufacturers to reduce salt in processed food?
“In 1997 three quarters of our salt intake came from manufactured foods. Many large and small food manufacturers are already doing great work in this area to incrementally reduce salt levels allowing people’s taste preferences to adjust. We are currently working collaboratively with key members of the food industry to map out and agree on a way to achieve further reductions in areas where there is room for improvement. This has already been successfully achieved in the majority of breads sold in New Zealand.”
Further Information
To talk to any of the experts quoted above contact the Science Media Centre on tel: 04 499 5476 or email: smc@sciencemediacentre.co.nz.
Notes to Editors
The Science Media Centre (SMC) is an independent source of expert comment and information for journalists covering science and technology in New Zealand. Our aim is to promote accurate, bias-free reporting on science and technology by helping the media work more closely with the scientific community. The SMC is an independent centre established by the Royal Society of New Zealand with funding from the Ministry of Research, Science and Technology. The views expressed in this Science Alert are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees. For further information about the centre, or to offer feedback, please email us at smc@sciencemediacentre.co.nz.