Popular condiment could be harming your mental health – ‘raising your risk of depression’
A COMMON condiment sprinkled on most meals could be to blame for your depression, researchers have suggested.
Their study, conducted on mice, showed that eating too much salt could negatively affect mental health.
A diet high in sodium can increase your risk of heart disease, stroke, and kidney disease.
Now, scientists from Nanjing Medical University say it could impact mental health too, after they found that mice who were given salty foods developed depression-like symptoms.
They said this was because the high salt diets affected the production of the cytokine IL-17A.
Cytokines are signalling proteins that help control inflammation in your body.
They allow your immune system to defend your body if germs or other substances that can make you sick enter it.
IL-17A is one of those infection-fighting proteins that helps recruit other immune cells to the site of infection and makes the body’s defences stronger.
The cytokine has previously been linked to depressive symptoms.
Lead author Dr Xiaojun Chen said:“This work supports dietary interventions, such as salt reduction, as a preventive measure for mental illness.
“It also paves the way for novel therapeutic strategies targeting IL-17A to treat depression.”
It’s not the first piece of research to look into the connection between diet and depression.
Previous studies have linked ultra processed foods – which tend to be high in salt, sugar and fat – to an increased risk of developing depression.
To examine the effect of salt on mental health, scientists gave mice either a normal or high-salt diet for five to eight weeks and observed their behaviour.
After five weeks, the mice gorging on salt showed less interest in exploring and were more inactive compared to mice fed a normal diet, suggesting depression-like symptoms.
The study – published in The Journal of Immunology – showed that mice fed lots of salt also experienced an increase in the production of IL-17A in their cells, spleens and certain areas of the brain.
Researchers also observed the behaviours of mice who couldn’t produce IL-17A as they didn’t have a specific receptor.
These mice didn’t display depression-like symptoms when being fed a high salt diet.
Researchers said their findings “suggest that [a high-salt diet] drives depression-like behaviour in mice through inducing IL-17A production.”
Finally, the study authors shut off cells producing IL-17A in mice experiencing depressive symptoms for their salty diets.
How much salt should you be eating a day?
Here's how much salt you should have daily according to your age:
- 11 years and over – No more than 6g (around one teaspoon)
- Seven to 10 years old – No more than 5g
- Four to six years old – No more than 3g
- One to three years old – No more than 2g
- Under one year old – Less than 1g
Here are some ways to reduce salt consumption:
- Try adding flavour to your food with herbs and spices, black pepper, garlic, chili or lemon juice instead of salt
- Limit the amount of salt you add when cooking and eating – try tasting your food before adding any extra salt to your meals
- Check food labels – look for products with green and amber colour-coded labels on the front of the packaging
- Choose lower-salt foods by checking the salt content on the back or side of the packaging
- Try low or reduced-salt versions of foods and sauces – for example, low salt soy sauce and stock cubes
- Buy tinned vegetables, pulses or fish in water instead of brine
- eat salty foods less often or in small amounts – for example, cured meats and fish, cheese, olives and pickles
- Have healthier snacks, such as plain rice cakes, fruit, vegetable sticks or unsalted nuts
- Be aware that some dissolvable tablets, such as painkillers, vitamins or prescription medicines, may be high in salt – speak to your GP before changing any medicines
- Don’t have salt on the table if you’re trying to cut down
Source: NHS
They found that this seemed to diminish depressive behaviour in mice.
Under NHS guidelines, adults should consume no more than one level teaspoon of salt a day to lower the risk of high blood pressure.
This amounts to 6g of salt a day and includes salt that’s already added to food as well as what you sprinkle onto your meal.
“We hope these findings encourage discussions on salt consumption guidelines,” Dr Chen said.
Richard Calderone, an osteopathic physician who was not involved in this study, noted to Medical News Today: “Although these findings were in mice, it is reasonable to investigate the effect of limiting salt intake on depression in humans.
“It should be noted that depression is a complex, multi-factorial condition, and that even with promising studies like this, it remains too early to know the quantity of salt intake necessary to demonstrate any clinical difference in humans.
“The study provides a biological explanation for the association between high salt intake and depression, identifying new targets for potential treatments.”