(RxWiki News) Salt and high blood pressure may go together like ham and eggs.
That’s the message from a new Japanese study that tracked people’s blood pressure and salt intake. They found that people with high salt intake were more likely than those who ate less salt to have high blood pressure.
Also, as salt intake increased over time, so did blood pressure, the authors of this study found.
“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 lead author Tomonori Sugiura, MD, PhD, in a press release.
Ruby Elizabeth Kassanoff, MD, FACP, a board-certified internal medicine specialist on the medical staff of Baylor University Medical Center at Dallas, told dailyRx News, "Hypertension is rare in societies with an average sodium intake of less than 1.2 grams of sodium per day. This suggests that sodium intake is risk factor for hypertension, independent of other risk factors such as obesity. The average sodium intake in the United States is about 3.4 grams per day, less than the 4.5 grams/day average seen in this study."
Dr. Sugiura, of the Nagoya City University Graduate School of Medical Sciences, and colleagues studied more than 4,000 people who had normal blood pressure at the start of this study. Patients ranged in age from 22 to 85.
Dr. Sugiura and team determined salt intake by measuring the amount of salt (sodium) in people’s urine.
At the end of this three-year study, 23 percent of the study patients had developed high blood pressure.
The patients who ate the most salt were more likely than those who ate less to develop high blood pressure, Dr. Sugiura and team found. People who gradually increased their salt intake over the three-year period were also more likely to develop high blood pressure.
Those who ate the least sodium took in 2,925 milligrams per day on average. Those who ate the most took in 5,644 milligrams per day.
Not all people develop high blood pressure, but Dr. Kassanoff says some are at higher risk.
"Salt sensitivity increases with age and is more marked in African-Americans, obese individuals and patients with metabolic syndrome or chronic kidney disease," Dr. Kassanoff said. "Unfortunately, there is not a way to predict which particular patients may be at higher or lower risk for salt sensitivity, so a general restriction for the population as a whole is recommended."
Sodium may increase blood pressure because it makes the body retain water. High blood pressure increases the risk of heart attack, stroke and heart failure.
Commercially processed foods like breads, cold cuts and cured meats are some of the highest-salt foods in the US diet. Pizza, poultry, soup and sandwiches also contain lots of salt.
“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," Dr. Sugiura said. "Reducing sodium intake can save lives, save money and improve heart health — no matter what background or nationality a person is.”
Dr. Kassanoff noted that keeping salt intake under control has other benefits.
"Not only does salt restriction prevent the development of hypertension, but it can also enhance the response to most antihypertensive drugs in patients who have high blood pressure," she said. "Other benefits of salt restriction include decreased risk of calcium-containing kidney stones and decreased risk of osteoporosis."
This study was published in the July issue of the Journal of the American Heart Association.
Dr. Sugiura and team disclosed no funding sources or conflicts of interest.