A diet high in salt has long been associated with raised blood pressure, a primary cause of heart attacks and strokes. However, new science suggests that heavy salt could also adversely impact the immune system too.
British guidelines suggest that we should not consume more than 6g of salt per day in total, that’s just over a teaspoon. However, many of us exceed this by an average of 2g; research suggests Brits take in around 8g per day.
Furthermore, the World Health Organization (WHO) recommends that we cap our daily salt consumption to 5g, so taking in 8g is 60% higher than it should be.
German researchers found that mice fed high salt diets tended to suffer much more severe bacterial infections. Human volunteers who consumed an additional 6g above the WHO recommendations showed deficiencies in their immune system.
It is believed that the mechanism behind this is through the filtration process in the kidneys. It’s important that the body keeps salt balance in check, and excess salt is filtered through the kidneys and excreted in the urine.
However, this has a side effect of causing an excess accumulation of glucocorticoids, a hormone that reduces the impact of the immune system, specifically, a type of immune cell called granulocytes that hoover up bacteria in the body.
If the body has a reduced ability to neutralise unwanted, disease-causing bacteria, it exposes us to an increased risk of infection such as listeria. Listeria is a bacterial infection contracted through contaminated food.
In the human volunteers’ blood, after just one week of eating a high salt diet, the scientists found higher levels of glucocorticoids and reduced granulocyte ability to cope with bacteria in a laboratory setting.
The obvious drawback of this study is that the scientists looked at granulocyte behaviour in an unnatural setting, as they’re used to working within the environment of the human body.
However, this work could contribute to other negative impacts high salt has on our health if other studies are able to replicate this finding, particularly in vivo.
It makes no difference what type of salt you consume either! Pink Himalayan, organic sea salt, or standard table salt – they all contain sodium chloride, which is the principle compound that is behind adverse health conditions.
Foods high in salt
Foods highest in salt according to nutritiondata.com include the following:
- Stock cubes and bouillon; dry soup powders; dry gravy powder/granules; dry sauce powders
- Tinned soup
- Noodle packs
- Salted fish
- Soya sauce
- Yeast extract spread (Marmite, Vegemite)
- Snacks: crisps, salted nuts, bread and cracker bites, pork skins
- Cured meats
By Ribbens Liz at pxhere.com
Seb is a writer and blogger of food and nutrition. He holds a bachelors and a masters degree in nutrition science, and has studied sports and exercise nutrition at postgraduate level. He specialises in plant-based nutrition and believes passionately that we can all live with a little less meat.