Dr. Walter Kempner — famous for creating the Rice Diet — was the first to discover that a salt-restricted diet can be used to treat people suffering from hypertension all the way back in the 1940s. So, why are we still talking about it? A recent study conducted by researchers from the Nagoya City University Graduate School of Medical Sciences in Nagoya, Japan has found that blood pressure readings could be the best indication for excessive sodium consumption.

The American Heart Association recommends consuming no more than 1,500 milligrams of sodium per day. One out of every three Americans has high blood pressure, and all too often a high-sodium diet is to blame. Consuming a lot of sodium causes high blood pressure by holding excess fluid in the body, which means an added burden on our hearts. Many people with high blood pressure early in life end up developing more serious conditions, including heart attacks, stroke, and heart failure.

"In our study, it did not matter whether their sodium levels were high at the beginning of the study or if they were low to begin with, then gradually increased over the years — both groups were at greater risk of developing high blood pressure," said Dr. Tomonori Sugiura, the study's lead author and an assistant professor in the Department of Cardio-Renal Medicine and Hypertension at Nagoya City University, in a statement.

Sugiura and his colleagues recruited over 4,000 people from Japan who had normal blood pressure readings at the start of the study. Each participant visited their health care provider for a routine check-up at baseline, and then follow-up urine analyses for around three years. Researchers used the amount of sodium in the participant’s urine to estimate the amount of salt that individual was consuming.

By the end of the study, around 23 percent of participants developed high blood pressure. Participants who consumed the most sodium (5,644 milligrams per day) faced the highest risk of high blood pressure, while those who gradually increased their sodium intake also increased their risk over time. Although the study focused on people from Japan, the research team assured that the results could also apply to Americans.

"Americans consume an average of nearly 3,500 milligrams of sodium a day, which is about 1,000 milligrams more than any public health group recommends," Sugiura said. "Reducing sodium intake can save lives, save money and improve heart health — no matter what background or nationality a person is."

The AHA also offers an effective way to track our sodium. The Sodium Tracker is an easy way to decide whether what you’re eating is considered part of a low- or high-salt diet. If you’re under the impression you know all there is to know when it comes to salty food, think again.

Source: Dohi Y, Ohte N, Kimura G, Takase H, Sugiura T. Dietary Sodium Consumption Predicts Future Blood Pressure and Incident Hypertension in the Japanese Normotensive General Population. Journal of the American Heart Association. 2015.