Salt - friend or foe?

As a scientist I always try to question medical advice, even if it is perceived wisdom. One such topic that I have always taken the contrarian viewpoint on is the widely accepted position that salt is bad for you and that people should limit their intake.

From looking at the studies I was never convinced by this even though it was widely accepted, and the theory is now being increasingly questioned.

High blood pressure causes extra strain on the heart and is one of the risk factors for heart disease. Avoiding high blood pressure is one of the most important things we can do for our health, which is one reason I support natural therapies and practices that can reduce stress, such as aromatherapy, yoga and massage.

In theory, large amounts of salt in the diet will increase your blood pressure, but the scientific evidence to support this is weak. In fact, it seems that if a person’s kidneys are working normally, as most people’s are, then they will simply excrete any excess salt with no negative effects. However, multiple Government regulatory agencies and clinical organisations, including the European Food Safety Authority, the US Centers for Disease Control, and the American Heart Association all recommend that consumers use less salt in their diets. The World Health Organisation has a goal to encourage reducing global salt consumption by 30% by 2025. Some countries and USA states have taxes and laws to reduce salt consumption.

However, a recently published study in The Lancet concluded that the vast majority of us are not being harmed by our level of salt intake. The study of more than 95,000 people found little or no harm up to a daily intake of 2.5 teaspoons (5g of sodium) a day. The researchers said that more than 95% of people in developed nations are below that level. Further, they found that even levels of salt intake that are too high can be counteracted by a diet that is rich in fruits, vegetables, dairy foods, potatoes, and other potassium-rich foods. This contrasts with health guidelines which usually recommend that salt intake is limited to around
1.5 - 2g/day.

Also, evidence is emerging that the message to lower salt intake has gone too far, and that having too little salt in the diet can be just as bad as having too much. A review of 25 studies with nearly 300,000 people in them concluded that both low salt intakes and high salt intakes are associated with increased mortality. It is unclear exactly how too little salt intake can be harmful, but it could be because it leads to increased cholesterol levels and/or because a low-salt diet may increase insulin resistance.

So what is my advice? Make sure you have your blood pressure checked regularly. If it is high, and you have a lot of salt in your diet, then it may be worth reducing your salt intake to see if this helps your blood pressure. But for the rest of us, make sure you have some salt and enjoy plenty of guilt-free salt if you like it.