Sodium Claims on Food Labels

You're probably well aware of the relationship between high sodium intake and the increased risk of high blood pressure and heart disease. Because processed foods are the largest source of sodium in a Western diet, many countries allow specific health claims related to sodium to be listed on a food's label in addition to the sodium information listed in the Nutrition Facts.

The theory is that if manufacturers put these health claims on a food's label, consumers should find it easier to make healthier food choices. This of course assumes that people understand what these health claims mean, believe them, and actually make food choices on that basis. Researchers at the universities of Toronto and Guelph, in Canada, realized that what evidence existed to back up these assumptions is at best outdated, and designed a study to assess consumers' attitudes and beliefs about sodium claims in particular (Am J Clin Nutr 2013;97(6):1288-98).

In Canada, health claims on food labels come in two forms: a disease risk reduction claim and a nutrient-function claim. Manufacturers are also allowed to make "nutrient content" claims. The researchers created a fictional soup brand, "Country Ladle Soups," and designed a tomato soup label for their study that would carry one of four special labels in addition to the usual nutrition facts box:

1. A disease reduction claim: "A healthy diet containing food high in potassium and low in sodium may reduce the risk of high blood pressure, a risk factor for stroke and heart disease. Country Ladle Tomato Soup is low in sodium."
2. A nutrient function claim: "Low sodium intake helps maintain healthy blood pressure."
3. A nutrient content claim: "Low in sodium."
4. or a general, non-health claim: "Tastes great!"

Over 500 Canadian consumers completed an online survey in which they viewed pictures of each soup label type then answered questions about how much they liked the claim on the package, whether they believed the claim, how clear the wording of the claim was, and how healthy they thought the food was for themselves or for others. They were also asked how likely they were to purchase that product with that label. Finally, the participants responded to a demographic questionnaire which included questions about whether they had been diagnosed with high blood pressure.

Here's what the researchers found: all of the claims mentioning sodium were considered equally believable, but the soup that the respondents considered the healthiest was the soup with the disease reduction claim on the label. They were most likely, however, to purchase the soups with the nutrient content claim or the disease reduction claim. Those participants with high blood pressure themselves found the nutrient function claim to be more useful than those who did not have high blood pressure.

Here'sthe kicker, though: all of the fictional soup labels carried exactly the same nutrition facts box. Only the claims emblazoned on the "front" of the can were different.

The researchers concluded that, contrary to the beliefs of those in the food industry who said that consumers saw "healthy" foods as not tasting as good, putting health-related labeling on a product did not make people less likely to purchase the product. The problem I see with that conclusion is that responding to a survey is one thing - actually making the purchase is something else altogether, and it's possible that the respondents' awareness that they should choose what they perceived to be the healthier item led them to skew their preferences towards the items with the sodium claims on the labels.

What this means for you

The take-home message here is twofold: first, don't just trust the health claims on the front of the label. Here's a guide to understanding those claims and knowing when they are useful. Second, be an educated consumer and apply your knowledge to reading the actual nutrition facts table on the item. Don't let your food choices be made or influenced by marketing.

First posted: July 10, 2013