In a recent survey, most adults with diabetes knew that a high-salt diet is linked to high blood pressure and stroke - but most still consumed too much sodium anyway.

“Despite knowledge that a high salt diet is related to high blood pressure it was not a high level of concern for this population group,” Kristy Gray, a researcher with the University of South Australia School of Pharmacy and Medical Science in Adelaide, and her coauthors wrote in the journal Appetite.

Although there is some controversy about optimum sodium intake, the authors say there is also good evidence showing a reduction in salt intake may help prevent strokes, heart attacks and other cardiovascular events.

Moreover, people with diabetes are already at higher risk of cardiovascular disease, so they need to be extra careful, the authors point out.

Gray and her colleagues reviewed questionnaires answered by Australian adults with type 1 or type 2 diabetes. They also measured participants’ blood sugar, blood pressure, and the amount of sodium in their urine.

Of the 143 people who participated in the study, only about a third knew that salt contains sodium. Only 6 percent knew that the recommended upper limit for salt intake for Australians is 6 grams per day.

More than 80 percent knew that processed foods such as bacon and pizza are high in salt, and 90 percent knew that foods such as carrots are low in salt. But fewer than 30 percent of participants knew that white bread and cheese are high in salt.

About half of the study group believed their health would improve if they lowered their salt intake and three quarters agreed that food manufacturers should do more to reduce salt.

But when asked which nutrients were their biggest “concern,” 65 people listed sugar, 41 said saturated fat, 35 said fat in general and only 10 said salt was their biggest worry.

Almost three-quarters of the participants said they look for the sodium content of foods when shopping and 38 percent said they often buy low- or reduced-salt foods.

And people who said they read the food labels tended to report lower sodium intake, although there was no connection between label reading and sodium levels in urine, suggesting that even people trying to be careful about salt were still consuming too much of it.

On average, people with type 1 diabetes had lower sodium intake than those with type 2, and men had higher intake - a median of 2,907 milligrams a day - compared to women, with a median of 1,962 milligrams a day.

Healthy people should limit their total sodium intake to 2,300 milligrams a day, or about the amount in a tablespoon of salt, according to the U.S. National Institutes of Health. For adults with high blood pressure, the recommendation is no more than 1500 milligrams a day.

Lauren Graf, a dietitian at Montefiore-Einstein Cardiac Wellness Program in New York, called the new study interesting, and consistent with other research on hidden sodium in processed foods.

But hidden sodium is only one of many unhealthy aspects of processed foods that have the potential to affect heart health directly and indirectly, Graf pointed out.

“The ‘elephant in the room’ that they're not saying is that there are so many things wrong with a lot of the processed food,” she told Reuters Health.

“So they're basically trying to attribute the role of nutrition and blood pressure to one micronutrient - sodium - and the reality is there are many factors,” said Graf, who wasn’t involved in the study.

As an example, Graf said that refined carbohydrates also tend to raise blood pressure.

“If a diabetic were to choose a low-sodium version of a highly processed cereal or bread, they're going to have a false sense of security in terms of doing something good for their health because they should be limiting a lot of those foods for a lot of reasons,” she said.

Graf said the focus should be on shifting to eating real food and less processed food, which will automatically reduce the sodium content and increase the intake of beneficial antioxidants and fiber.

“There's a lot of antioxidants in green leafy vegetables and dark chocolate and nuts that actually seem to make the blood vessels more flexible and improve blood pressure,” she said.