Thursday, 24 June 2021

More than a pinch of salt and you’re encouraging health problems

ONE of my go to lines when advising patients on how to lower their blood pressure is to watch their salt intake.

The advice that you should avoid eating too much salt in order to prevent high blood pressure and therefore heart disease and stroke, is unrefuted yet you will often see headlines popping up in newspapers and magazines about how salt is actually good for you.

Of course this is true up to a certain point but only in so far as salt, or more specifically sodium chloride, is an essential substance without which we could not live.

On reading this you might be thinking what’s all the fuss about then? Well, like so much of what we physicians advise, moderation is the key.

Let me begin with what salt is and how we use it. Chemically speaking, a salt is any chemical compound formed from a reaction of an acid with a base. Colloquially, however, we refer to sodium chloride as salt and that’s what I’m referring to here.

Sodium chloride is found naturally in our environment. We mine it to provide table salt but it can also be derived from sea water, in which case it is often referred to as sea salt.

Once in the body, the components of salt are ionised and so we have separate sodium and chloride ions circulating within our bloodstream.

Sodium in particular is a key mineral and has a fairly narrow optimal range of concentration within our blood. At high or low dilutions, it affects how much fluid we retain or get rid of and so in essence is integral to how our bodies regulate fluid balance within the bloodstream and within our tissues.

Our bodies only need so much and getting too much of it, which is very easy to do in this day and age, is where it becomes harmful.

For example, if the levels of sodium in the blood go beyond their optimal range, more and more fluid is retained which in turn increases the circulating volume of the blood and that is where the rise in blood pressure comes from.

If the levels in the body tissues are too high, the same thing happens, causing oedema (swelling of the tissues from water retention).

The trouble is that the body has to dilute a high sodium level or else it may cause all sorts of problems, including extreme fatigue, confusion, muscle twitching and seizures.

The only thing we can change then is how much we ingest.

The official recommendation for salt intake for an adult in the UK is no more than 6g a day. This is 2.4g of sodium (sodium chloride consists of 40 per cent sodium and 60 per cent chlorine so it is worth noting that sometimes food packaging lists sodium levels and not overall salt. If so, just multiply the sodium content by 2.5.) In reality, we are eating more like 8.4g on average each day (9.2g for men and 7.6g for women).

Considering that around 31 per cent of adults in England are affected by high blood pressure, it is thought that if the population average salt intake is reduced by just 1g per day, it could prevent more than 4,000 premature deaths and save the NHS £288 million each year. We have long had a close relationship with salt, although there appears to be no consensus from scientists as to why we like it so much.

Interestingly, some observation studies have found that people can be trained to be satisfied with lower salt content in their foods. Participants found their previous salt contents too salty when reintroduced.

Of course, we have used it for more than just flavouring our food in days gone by. It was referred to as “white gold” such was its value in Roman times.

Part of its draw was its ability to work as a preservative for meats and fish. The Latin word for salt is “sal” and so, due to its worth, it was used as a currency, giving rise to the word salary. The common phrase “to be worth your salt” is indicative of someone “worth their pay”.

These days, to complicate matters, there appear to be a lot of different types of salt out there. Since the Twenties, most salt will have been fortified, or iodised, with iodine.

Iodine in the diet is important for the development of children both in the womb and while growing and having a reliable source of it means our thyroid glands have enough resources to continue producing thyroid hormone. However, this is not a reason to eat over and above the normal salt levels, as some headlines might have you believe. Nor should we be rushing to have more sea salts or all the snazzy colourful ones like Himalayan salts (although they might be a bit more flavourful).

These types differ from table salt in that they will likely contain other minerals such as magnesium, potassium or calcium, all vital certainly but also things you will be getting plenty of in your normal diet as long as it is balanced.

Epsom salts, if placed in a bath, are claimed to absorb more magnesium through the skin and are anecdotally supposed to soothe muscle aches. That’s all fine but the bottom line is that salt intake should be limited and shouldn’t be relied upon to gain other minerals. Again, just eat a normal diet.

It’s thought that around three quarters of the salt we ingest is already added to the food we eat before we buy it. Over the years there have been attempts to regulate the food industry to slowly reduce salt contents, possibly the only way to get the blanket reduction necessary to train our palates without giving unfair advantage to companies who might then sneakily appeal to our “salt tooth” (I made up the phrase but you know what I mean).

Still, we need to be actively cutting down on our salt intake. That means checking labels closely. Processed pre-packaged meals are terrible for salt content — natural, fresh cooked ingredients are preferable.

Bread is not necessarily high in salt but it certainly contains its fair share and because we eat so much of it we’re getting too much salt from this route as well.

We also need to add less when actually cooking and should never be adding salt at the table. As alternatives for flavour, you might want to try pepper, herbs, spices or lemon juice instead.

Be wary of cooking sauces, which are often also very high in sugar content, and cut way back on the salty snacks, crisps, salted nuts etc.

Doing this could really make a difference. Not only will it reduce your risk of heart attack or stroke but it is thought that people who suffer from asthma, Meniere’s disease, migraines and kidney stones, to name a few, could also benefit from a low salt diet.

A pinch of salt is fine once in a while but any more than that and you’re not doing yourself any favours.

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