While most of us know we should cut back on salt, Australians consume on average nearly double the recommended daily maximum per day.
Salt has been used in food storage for centuries and idioms like “worth your weight in salt” indicate how valuable it was to preserve food to ensure survival. Salt absorbs moisture from food, limiting bacterial growth that would otherwise spoil the food and cause gastrointestinal disease. Today, salt is still added as a preservative, but it also improves the taste of foods.
Salt is a chemical compound made up of sodium and chloride, and this is the main form in which we consume it in our diet. Of these two elements, it is sodium that we need to worry about.
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So what does sodium do in our body?
The main concern of consuming too much sodium is the well-established link with the increased risk of hypertension (or hypertension). High blood pressure is in turn a risk factor for heart disease and stroke, a leading cause of serious illness and death in Australia. High blood pressure is also a cause of kidney disease.
The exact processes that lead to hypertension from consuming large amounts of sodium are not fully understood. However, we know that it is due to the physiological changes that occur in the body to tightly control the body’s fluid and sodium levels. This involves changes in how the kidneys, heart, nervous system, and fluid-regulating hormones respond to increased sodium levels in our body.
Maintaining tight control over sodium levels is necessary because sodium affects the membranes of all individual cells in the body. Healthy membranes allow the movement of:
nutrients in and out of the cells
signals through the nervous system (for example, messages from the brain to other parts of the body).
Dietary salt is needed for these processes. However, most of us consume far, far more than we need.
When we eat too much salt, this increases the sodium levels in the blood. The body responds by drawing in more liquid into the blood to keep the sodium concentration at the right level. However, as the volume of fluid increases, the pressure against the blood vessel walls increases, causing hypertension.
High blood pressure makes the heart work harder, which can lead to diseases of the heart and blood vessels, including heart attack and heart failure.
Although there is some controversy over the effect of salt on blood pressure, most literature indicates that there is a progressive association, meaning that the more sodium you consume, the more likely you are to die prematurely.
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What to pay attention to
Some groups of people are more affected by high-salt diets than others. These people are referred to as “salt sensitive” and are more likely to have high blood pressure due to salt consumption.
People most at risk include older people, those who already have high blood pressure, people of African American descent, those who have chronic kidney disease, those with a history of pre-eclampsia (high blood pressure during pregnancy), and those who they had a low birth weight.
It is important to be aware of your blood pressure, so the next time you visit your doctor be sure to get it checked. Blood pressure is given by two digits: the highest (systolic) and the lowest (diastolic). Systolic is the pressure in the artery when the heart contracts and pushes blood through your body. Diastolic pressure in the artery is when the heart relaxes and fills with blood.
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Optimal blood pressure is below 120/80. Blood pressure is considered high if the reading is above 140/90. If you have other risk factors for heart disease, diabetes, or kidney disease, your doctor may set a lower goal.
How to reduce your salt intake
Cutting down on salt in your diet is a good strategy for lowering blood pressure and avoiding processed and ultra-processed foods, which are about 75% of our daily salt intake, is the first step.
Increasing your fruit and vegetable intake to at least seven servings a day can also be effective in lowering blood pressure, as they contain potassium, which helps our blood vessels to relax.
Increasing physical activity, quitting smoking, maintaining a healthy weight, and limiting alcohol intake will also help maintain healthy blood pressure. Blood pressure lowering medications are also available if blood pressure cannot be reduced initially by lifestyle changes.
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