Both the British Heart Foundation and the American Heart Association recommend no more than 1 teaspoon of salt per day. Any more than this, they say may raise your blood pressure and increase your risk of developing coronary artery disease.
But is this really case the case? Apart from making food taste better, salt has a number of benefits in the body, particularly where the immune system is concerned. Salt draws the anti-inflammatory part of the immune system to the barriers of the body such as the skin and the digestive tract and can protect against bacterial infection. Indeed it has been hypothesized that our hunter gatherer ancestors, to whom we are genetically similar, died of infections because of the lack of salt in their diet. They would typically have had only 680 mg of sodium per day in their diet compared with our 4 – 14 grams. And the amount of salt in the blood has an impact on your blood pressure system.
Your blood pressure system is known as the renin–angiotensin–aldosterone system (RAAS). It is a hormonal system that regulates the amount of sodium in the blood. Sodium along with water and glucose is essential to our survival which is why when we sense ‘danger’ this system is always activated to directly or indirectly conserve these substances. Danger to our ancestors would have been hunger or thirst, for example, but nowadays it is anything from cycling in traffic to meeting the mortgage payments every month. In times of stress, our digestive tract also becomes permeable to allow salt, water and glucose into the bloodstream. This situation is fine if the reason for the stress reaction is resolved but if it becomes a chronic problem then high blood pressure can be the consequence.
But what else can activate the blood pressure system? A meta-analysis, combining results from a number of studies, in the American Journal of Hypertension say the following ‘ both a low and excessive sodium diet are associated with increased mortality’. They found that we really needed to have an intake of between 2645-4945 mg per day if we did not want to have raised blood pressure levels.
So what does this mean in practical terms? Food labelling will typically give the sodium content of foods so 1 teaspoon of salt will be equal to 1300mg of sodium. This means that a healthy daily intake of at least 2 teaspoons of salt is necessary to meet the minimum requirement to keep blood pressure at bay. This is twice what is recommended by the British Heart Foundation and American Heart Association.
If you eat a high amount of processed foods you will not need to add more salt but if you are eating a whole food diet you will. But rather than create an electrolyte imbalance you might want to make sure your vegetable intake to give you plenty of potassium and consider magnesium supplementation.