International comparisons show that fast foods don't have to contain so much salt.
Salt levels in fast foods vary tremendously from chain to chain and country to country.
Reducing sodium in foods requires reformulating entire recipes.
People don't notice gradual drops in sodium of 10 percent or less at a time.
Depending on where you are in the world, identical dishes at fast food restaurants contain vastly different amounts of salt .
Canadian Chicken McNuggets, for example, have nearly three times more sodium than the ones served up at McDonald's restaurants in the United Kingdom. And a Subway club sandwich in New Zealand has more than twice the salt as the same sized sandwich in France.
The findings of the new study suggest that it should at least be possible to reduce levels of salt on North American fast food menus despite industry resistance to sodium-reductions and claims that technological limitations prohibit a shift to less salt on their menus.
Because most of the sodium in our diets comes from processed foods, lowering their salt content could go a long way towards reducing high blood pressure and other salt-related health problems. That's something public health experts have been pushing companies to do for years.
"One of the major arguments against reducing salt in food is that it costs so much to develop new products and people might not like it and we don't have the technology and all these problems," said Norm Campbell, a hypertension expert at the University of Calgary. "But that's not true. We already have these less salty products. It is certainly possible from a technological basis."
"Our study," he added, "shows that a number of these technological barriers are window-dressing excuses for inaction."
The Institute of Medicine recommends that most healthy adults consume less than 2,300 milligrams of sodium each day, though about half of the population would do well to cut themselves off at 1,500 mg because of age, ethnicity or health conditions. Despite years of public health warnings, though, the average consumption of sodium for Americans over age two remains close to 3,500 mg a day.
Only about 10 percent of the salt we eat comes out of a shaker directly onto our food. The vast majority -- close to 80 percent -- lurks in processed products.
That has led the New York City Health Department to coordinate a national-level effort to reduce sodium levels in packaged and restaurant foods. And some fast food companies have vowed to lower salt levels on their menus.
But companies often say that there are technological barriers to getting the salt out. That's because salt does far more than just add salty flavors. It also enhances sweetness, blocks bitterness, masks off-tastes, alters texture and more.
"Salt is this magic ingredient that does all sorts of things," said biologist Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia. So, when you take salt out, "you have to redesign the food."
To see whether fast food companies had truly reached the point where removing salt would ruin their products, Campbell and colleagues collected standardized nutritional information from seven countries on six categories of food from six restaurant chains, including Pizza Hut, Burger King and Kentucky Fried Chicken. Food categories included breakfast items, fries, pizza and salads.
Salt levels varied dramatically in foods both within and between countries, the researchers report today in the Canadian Medical Association Journal.
From chain to chain in the United States, for example, burgers contained between 0.8 and 1.8 grams of salt in each 100 g of food. In Australia, pizzas contained anywhere from 0.5 to 2 g of salt for each 100 g of food. And compared to sandwiches at Subway, sandwiches at Pizza Hut had 70 percent more salt.
The researchers did not break down their data into mg of sodium, which are the units most of us use to gauge salt levels. But the results show that a value meal at one restaurant can have two or three times more sodium than one at a different chain down the road.
And it's no secret that sodium levels can be quite high in fast foods: A Big Mac at an American McDonalds, for example, contains 1040 mg of sodium, according to the company's website. A 10-piece Chicken McNuggets has 900 mg.
Overall, salt levels in Canada and the United States tended to be higher than those in the UK, where strong pressures and influential salt-reduction campaigns have made a more substantial impact.
The new study supports the IOM's recommendation that a gradual reduction in sodium in processed and fast foods could meet public health targets without alienating the American palate, Beauchamp said. Studies show that reducing sodium by 10 percent or less at a time is subtle enough to escape notice.
"If you mean, is it possible to do this and still have food that is safe, the answer is obviously yes, it could be done," Beauchamp said, but motivation for such a change will need to be strong and everyone will need to be on board.
"In a free society, how do you coordinate companies to do this in concert?" he asked. "If companies aren't on a level playing field, it is very difficult if one company does it and one doesn't. This will take some time and work."