Wherever you look in the world, salt intake is higher than it should be. Of all the deaths from heart disease, excess salt intake is a significant cause in more than 1.5 million of them. Salt raises blood pressure and makes the natural increase of blood pressure with age worse, and therefore the risks of stroke and heart attacks go up. But that’s just part of the story. There are growing suspicions that salt increases oxidative stress and inflammation (two of the biological processes behind ageing) and may increase the risk of Alzheimer’s disease and autoimmune diseases like rheumatoid arthritis. Salt is of course addictive and makes food taste good. Most salt comes from processed foods rather than the salt you add and making flavoursome, herb dense meals distract from needing added salt. Reducing how much you eat through portion control will naturally reduce your salt intake.
There is confusion about knowing how much salt you’re eating. There are two measures: sodium and salt. Sodium is what does the damage, but it comes in salt which is sodium chloride and salt weighs 2.5 times more than its sodium content. The aim should be to keep your sodium intake to 2 grams a day. That’s 5 grams of salt. So if the pack says there’s 500mg of salt in a serving, that’s 200mg of sodium which is 10% of your target intake. 5 grams of salt is about a teaspoonful.
Salt intake by Australians is double the recommended intake in men and 50% greater in women. A review of data on almost 17,000 Australians where their salt intake was quite accurately measured, found that men were consuming over 10 grams of salt a day and women well over seven grams. That’s a lot of extra sodium a day and mostly from processed foods including bread.
Salt increases your blood pressure and your risk of heart attacks and strokes in various ways. Too much sodium in the blood makes your kidneys retain more water and that raises blood pressure. It’s also clear that excess sodium can damage arteries and is linked to stiffer, less elastic arteries which in turn can make high blood pressure worse and cause kidney damage. High blood pressure and diabetes are the commonest causes of kidney damage as people age and kidney damage products premature death from heart disease.
The damage that salt can do to arteries – particularly the lining (endothelium) could be behind the observation that salt intake is related to the risk of Alzheimer’s disease. Experiments in mice have shown that dietary salt can induce the production of the tau protein which gums up the brains of people with cognitive decline and Alzheimer’s. One possibility is that salt increases oxidative stress in the memory part of the brain called the hippocampus. This oxidative stress may also increase the chances of cholesterol damaging the arteries through atherosclerosis.
Excessive salt intake is moderately associated with the risk of stomach (gastric cancer) in many studies. Salt may make the effects of the ulcer germ H. Pylori, worse and probably damages the stomach lining directly.
There is growing evidence of a link between salt intake and autoimmune diseases such as rheumatoid arthritis and perhaps multiple sclerosis. It’s early days in the research but the suggestion is that excessive sodium takes the foot off the brake which holds back the abnormal immune responses. This allows the immune system to become inflamed and attack various parts of the body such as the linings of the joints (rheumatoid) and nerves (MS).
If you’re not able to substitute potassium in your salt, then reducing your salt intake requires a bit of effort. A weight loss or weight maintenance diet with portion control will lower sodium intake just because you’re eating less. Cooking your own food rather than buying processed foods will help because you will be in control of the added salt. There is also evidence that you can fool your taste buds by the aromas from herbs, adding lemon juice to salads or cooked vegetables, using coarse pepper and even tiny amounts of ham.
Unlike cholesterol where you really cannot go too low, with salt there’s probably a sweet spot at around the recommended levels of two grams of sodium/five grams salt per day. While some people are more salt sensitive than others, there’s little doubt that if we can shift the average salt intake by the population downwards, it could have an enormous impact.
