Dr Alan Barclay
Is salt reduction the only answer to reducing the risk of dying of a heart attack or stroke?
“Cutting down on the amount of salt has no clear benefits in terms of likelihood of dying or experiencing cardiovascular disease (CVD).” reports a new Cochrane Review. Part of the reason for this discouraging result is the simple fact that large enough trials have not been run for long enough periods of time to prove that sodium reduction really does reduce the risk of heart attack and strokes (CVD).
To date, the evidence suggests that cutting back on dietary sodium may help reduce blood pressure by 1.1–4.1 mmHg in people with normal and high blood pressure, respectively. But salt reduction is not the only way of lowering blood pressure and therefore reducing the risk of death from a heart attack or stroke.
And focusing on sodium reduction alone often doesn’t work as the makers of Cambell’s Soup recently found out. If you lower the salt content of certain foods too much people simply won’t buy them anymore because they don’t like the taste …
- Losing 10 kg of excess body weight will reduce blood pressure by 5–20 mmHg
- Consuming a diet rich in fruits, vegetables, and low-fat dairy products with a reduced saturated and total fat content (i.e., the DASH diet) will lower blood pressure by 8–14 mmHg
- 30 minutes a day of regular physical activity (a brisk walk will do) will lower it by 4–9 mmHg.
What we need to remember is that there are many risk factors for the development of CVD (heart disease and stroke) including high blood pressure, high cholesterol and high blood glucose levels. For example, another mineral, potassium, also affects our blood pressure – high potassium intakes lower blood pressure which is why it’s important to eat more fruits, vegetables and wholegrains. And the type and amount of fat we eat has a powerful affect on our blood cholesterol levels.
Few people realise that the amount and type of carbohydrate that we eat also has an effect on our blood pressure. Dr Reaven was the first to describe the role of insulin resistance in the development of high blood pressure in the 1990s. Put simply, the kidney does not develop insulin resistance like the liver and muscles do, and as insulin levels get progressively higher in the blood, the kidneys increase their retention of sodium (in other words, we excrete less sodium in our urine), leading to higher blood pressure.
This is why an overall healthy diet that’s moderate in sodium, and lower in kilojoule/calories, saturated fat and high GI carbohydrates is the best way to reduce your risk of having a heart attack or stroke – not simply reducing the amount of salt or salty foods that you eat. And this is where front-of-pack labelling schemes like the GI Symbol can help. We developed category specific nutrient criteria for energy (calories/kilojoules), carbohydrate, fat, saturated fat, sodium, and where appropriate, fibre and calcium for the low GI Symbol to help make all-round healthy food choices in the supermarket easier for everybody, every day.
For more information about the GI Symbol Program
Dr Alan W Barclay, PhD
Chief Scientific Officer
Glycemic Index Foundation (Ltd)
Phone: +61 (0)2 9785 1037
Mob: +61 (0)416 111 046
Fax: +61 (0)2 9785 1037