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DiNicolantonio adds: “For 10 000 years, we have used salt as a natural preservative and have probably eaten 10 times as much as we do today. And in places associated with longevity and health – Korea, Japan, the Mediterranean countries – salt is still used more freely.”
However, for the past 40 years, salt has been very much a nutritional bad-guy. According to the British Heart Foundation, eating too much salt may raise your blood pressure, and having high blood pressure increases your risk of developing coronary heart disease.
The independent scientific lobby group Consensus Action on Salt and Health (Cash) recommends salt intake should be an average of 6g (about one teaspoon) a day for adults, and even less for children.
It believes this will have a hugely positive effect on national health: “This reduction will have a large impact on reducing strokes by approximately 22% and heart attacks by 16%, saving 17 000 lives in the UK as well as other health benefits for the population.”
In 2013, the World Health Organisation (WHO) revised its guidelines to suggest that adults should consume less than 5g of salt.
DiNicolantonio is not convinced. He says: “There has never been any evidence for the low-salt dogma; it was just written on the basis of a few opinions, and now gets repeated every five years.”
He adds: “It has never made sense to me consciously to restrict salt intake. The suggestion stems from the idea that we need to lower blood pressure and that by lowering salt intake, blood pressure will fall, too. But that’s not true: 80% of us will see no difference.
“And no one challenges the idea that it is a good idea to lower blood pressure. I can tell you to drink less fluid and that will lower your blood pressure but it isn’t healthy to become dehydrated.”
He also points out that our bodies are sophisticated machines capable of managing our own sodium levels – the essential mineral in salt that we need for many of the body’s processes.
He adds: “Healthy kidneys will get rid of excess salt, the gastro-intestinal system can stop absorbing it, or you may shunt excess salt into organs like the skin. And our bodies are set up so we simply don’t want to eat too much salt.
“On the other hand, if we lose too much salt, our bodies crave it.”
But DiNicolantonio warns that we can’t follow low-salt guidelines on a daily basis and then just top them up with a bag of popcorn when we get that salt craving.
“If your body feels sodium-deficient, it activates its reward system, ready to release feel good hormones when you eat something salty. But foods that are sugary or made of refined carbohydrates can ‘hijack’ that reward system, so you feel good eating a chocolate bar and no longer crave the salt you actually needed.
“It’s entirely possible that if you are avoiding salt, your brain could send you towards sugar or even drugs instead in order to get that reward feeling. And our bodies have no aversion signal for sugar to let us know when we have eaten too much.”
But what about children? The WHO says that its guidelines on the consumption of salt are particularly important for youngsters, as children with elevated blood pressure often grow into adults with elevated