Finding a Scientific Solution to Lowering Our Salt Intake

The USDA recommends we should be consuming, at most, 2,300 milligrams of sodium a day (that's about 1 teaspoon of salt). The American Heart Association believes that number should be more around 1,500 mg a day. However, the average American consumes around 3,400 mg a day.

You can see the problem.

A huge portion of that intake comes from processed foods (up to 70%). Meaning that for us to make a dent in our salt intake, we need to tweak how much salt goes into those foods. One study from the University of Illinois may have a found a solution.

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The study revolves around a relatively simple concept: A lot of salt inside of processed foods isn't even making it to our taste buds. Instead, it's locked inside and not released during the chewing process. So, if there was a way to hack into the microstructure in order to release more of the sodium to our taste buds, it wouldn't need to contain as much salt to taste the same. The implication of the finding is a pretty big:

[W]ith enhanced sodium release, a lower amount of sodium will be needed in the product, and thus consumers will be able to reduce sodium intake.

The study comes courtesy of Wan-Yuan Kuo and Youngsoo Lee from the Department of Food Science and Human Nutrition at the University of Illinois. I spoke to Youngsoo Lee about the study and what the findings mean.

Why did you start looking into salt intake?

Youngsoo Lee: Initially I was thinking of trying to find a way to reduce sodium in foods in general, and narrow it down to different types of food. We found out that in protein and fat-based foods such as cheese, possibly up to 95% of sodium we add is not coming out when we chew. So, in terms of saltiness perception, we're wasting 70 to 95% of sodium. I'm a food engineer, so I was thinking what can we do to improve that sodium release during the mastication process, and that's where we actually started. Then we looked at the microstructure of food that's going to affect sodium release. Is it the pores, the size, how many pores, or is there something else that we can actually see that's going to govern the sodium release of mastication? That's where it all started.

Did you look at other ways to reduce sodium before?

Lee: Sodium reduction has been a big topic for a long time, for more than 40 years actually. One of the strategies is replacing sodium with something else, such as potassium chloride, things like that. So, this is my approach to reduce sodium in food. We want to increase the release of sodium, and we're hypothesizing that if we increase the release it will increase the sodium perception, so we don't need to increase the sodium in food. In terms of microstructure, we looked at the past research and found that the structure may be a big factor, but there is a clear discrepancy. People looked at fat size and fat amounts in food, and some say that if you have larger fat that will increase the saltiness, while others say that if you have a smaller fat size it will increase the saltiness. So there are some things that are not matching up. This is the first step.

What's the next step?

Lee: Next step would be doing a sensory study. We would test human subjects, ask them to chew and taste and evaluate how salty that is. What we're trying to do in terms of design is collect an amount of sodium in saliva during the chewing process so we will know how much sodium is coming out at different points of time in chewing, so we can relate that with both structure and saltiness perception. That's going to be the next step, and once we finish that we can formulate a generalized model to activate the saltiness based on the structure. Here is the fat size, here is the percent of fat, the protein, things like that. They all go into one equation, and by putting in all of that information we can activate what the saltiness can be when we consume this food. The next step should be how to apply this equation to actual food, to actual cheese, or actual sausage or hot dogs. We have to test those with the actual food and evaluate the equation.

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