Scientists suggest we may add extra salt to our food because it boosts our mood, even though we know too much is bad for us.
University of Iowa researchers writing in Psychology and Behavior say salt may act as a natural antidepressant. Tests on rats found those with a salt deficiency shied away from activities they normally enjoyed - a sign of depression. But experts warn eating too much salt is linked to high blood pressure.
The body needs sodium - which along with chloride makes up salt - to function, but having too much and raising blood pressure is linked to an increased risk of stroke and heart attack. The UK's Food Standards Agency says the average adult should eat no more than 6g of salt a day.
Intake is falling, but last year the average was 8.6g. Around three-quarters of the salt we eat comes in pre-prepared foods. The findings are published as the FSA renewed its advice for people to eat more healthily. It backed an independent panel of experts warning that celebrity chefs were promoting high-fat recipes, and contributing to the obesity crisis.