The modern diet of processed foods, takeaways and microwave meals could be to blame for a sharp increase in autoimmune diseases such as multiple sclerosis, including alopecia, asthma and eczema.
A team of scientists from Yale University in the U.S and the University of Erlangen-Nuremberg, in Germany, say junk food diets could be partly to blame.
‘This study is the first to indicate that excess refined and processed salt may be one of the environmental factors driving the increased incidence of autoimmune diseases,’ they said.
Junk foods at fast food restaurants as well as processed foods at grocery retailers represent the largest sources of sodium intake from refined salts.
The Canadian Medical Association Journal sent out an international team of researchers to compare the salt content of 2,124 items from fast food establishments such as Burger King, Domino’s Pizza, Kentucky Fried Chicken, McDonald’s, Pizza Hut and Subway. They found that the average salt content varied between companies and between the same products sold in different countries.
U.S. fast foods are often more than twice as salt-laden as those of other countries. While government-led public health campaigns and legislation efforts have reduced refined salt levels in many countries, the U.S. government has been reluctant to press the issue. That’s left fast-food companies free to go salt crazy, says Norm Campbell, M.D., one of the study authors and a blood-pressure specialist at the University of Calgary.
Many low-fat foods rely on salt–and lots of it–for their flavor. One packet of KFC’s Marzetti Light Italian Dressing might only have 15 calories and 0.5 grams fat, but it also has 510 mg sodium–about 1.5 times as much as one Original Recipe chicken drumstick. (Feel like you’re having too much of a good thing? You probably are.
Bread is the No. 1 source of refined salt consumption in the American diet, according to the Centers for Disease Control and Prevention. Just one 6-inch Roasted Garlic loaf from Subway–just the bread, no meat, no cheeses, no nothing–has 1,260 mg sodium, about as much as 14 strips of bacon.
The team from Yale University studied the role of T helper cells in the body. These activate and ‘help’ other cells to fight dangerous pathogens such as bacteria or viruses and battle infections.
Previous research suggests that a subset of these cells – known as Th17 cells – also play an important role in the development of autoimmune diseases.
In the latest study, scientists discovered that exposing these cells in a lab to a table salt solution made them act more ‘aggressively.’
They found that mice fed a diet high in refined salts saw a dramatic increase in the number of Th17 cells in their nervous systems that promoted inflammation.
They were also more likely to develop a severe form of a disease associated with multiple sclerosis in humans.
The scientists then conducted a closer examination of these effects at a molecular level.