The evolution of salt

The Yellow Emperor’s Classic of Internal Medicine is an ancient Chinese text dating from 300 BC. A translation from the text reads,

If too much salt is used in food, the pulse hardens…

The Yellow Emperor’s Classic of Internal Medicine

The Chinese knew more than 2000 years ago that salt causes high blood pressure.

In chapter 7 of Dr Greger’s book, How Not to Die, he writes that after one salty meal, not only does blood pressure increase, but the arteries stiffen.

When I first decided to follow a low-salt diet I cleaned out my fridge and cupboard of all chutneys and sauces which tend to have a lot of salt. I am also fond of sauerkraut and pickles; they both got tossed out. I’ve also stopped eating out – if only restaurants served food without salt! People may think this is extreme but I think there’s something warped about a culture that thinks it’s more extreme to eat a healthy diet than to take prescription drugs. Plus I always welcome a good challenge!

For most of human history we have eaten very little salt. Humans in paleolithic times consumed less than 1g of salt per day. They also ate lots of fruit and vegetables and the potassium content of these fruit and vegetables counteracted the salt and lowered blood pressure. Today we have a double whammy because while our salt intake has increased 10-fold, our consumption of protective fruit and vegetables has plummeted.

The NHS website recommends no more than 6g of salt per day which is still 6 times higher than most of our evolution. Humans began consuming more salt in the last 5,000 – 10,000 years likely because they discovered salt can preserve food and eating salty preserved food was preferable to starving to death.

Salt does terrible things to the body. Too much salt in the blood causes the body to hold onto water in an attempt to dilute the excess salt. This results in more fluid in the blood stream and surrounding cells. The additional fluid forces the heart to work harder pumping blood around which puts more pressure on the vessels. This extra pressure causes the vessels to stiffen over time, exacerbating blood pressure, and causing heart attack and stroke.

Salt can also damage the heart, aorta, kidneys and cause other diseases independently of increasing blood pressure. For instance, your body loses more calcium via urination with diets high in salt which can cause osteoporosis even in the absence of high blood pressure. There’s also a link with stomach cancer.

Salt preference is malleable which means our tastes can change. If you eat a lot of salt and suddenly switch to a low-salt diet the food will initially taste bland. But after 4 to 6 weeks your tastes adapt and the food becomes flavoursome while salty foods become unpleasant. The downside to this is if I ever do decide to treat myself to a meal out it likely won’t taste very nice.

The rest of the family have been very accommodating and haven’t complained at all about the lack of salt. They can add it to their own plates if they want but so far none of them have. I rarely added it to cooking anyway as stock cubes have more than enough salt in them but I have also stopped using stock.

2 responses to “The evolution of salt”

  1. My mum’s always been really good about not using salt. We were always finding food too salty when we ate out, or if someone cooked for me and added salt when boiling vegetables. However I lost that when I left home and I usually add salt to cooking these days if I’m cooking (apart from boiling vegetables). I don’t think people would mind if I left it out, we are just conditioned to it being the correct thing to do.

    1. Yes that’s it exactly. We’ve become conditioned to it as the norm and avoiding salt is considered extreme.

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