Does high salt intake lead to cardiovascular problems? According to a study released in June, it does. A ‘more accurate’ test measurement showed a direct link between consuming high amounts of salt and an elevated risk of dying from cardiovascular disease.
The study, conducted by scientists at Brigham and Women’s Hospital, used multiple measurements to determine just how salt might affect cardiovascular health. The team writes in the International Journal of Epidemiology that salt intake has been inaccurately determined in the past.
Dr. Nancy Cook, a biostatistician in the Department of Medicine at Brigham and Women’s Hospital, said in a news release:
“Sodium is notoriously hard to measure. Sodium is hidden – you often don’t know how much of it you’re eating, which makes it hard to estimate how much a person has consumed from a dietary questionnaire.”
While there are numerous ways to measure sodium excretions, those methods aren’t always accurate, Cook said.
In order to accurately measure sodium levels in urine, the urine must be tested over 24 hours. This is because sodium levels in urine can fluctuate throughout the day. The researchers also say that samples should be taken on multiple days because sodium consumption can vary from day to day.
Cook and her colleagues used spot samples for the study, but they also utilized other methods, including the “gold standard” of analyzing an average of multiple, non-consecutive urine samples.
Additionally, the scientists analyzed records from participants in the Trials of Hypertension Prevention, which included 2,974 people with pre-hypertension aged 30-54 years. A total of 272 people died during the 24-year follow-up period.
The researchers’ updated method showed a direct linear relationship between increased sodium intake and increased risk of death. Using the gold standard testing method, the team found that the average sodium intake was 3,769 mg/d, and the average overestimated sodium intake by 1,297 mg/d.
The common Kawasaki formula used to judge salt intake showed a J-shaped curve, which suggests that both low and high levels of salt intake are linked to an increased risk of mortality from cardiovascular disease.
The authors wrote:
“Our findings indicate that inaccurate measurement of sodium intake could be an important contributor to the paradoxical J-shaped findings reported in some cohort studies. Epidemiological studies should not associate health outcomes with unreliable measurements of sodium intake.”
According to Harvard University’s T.H. Chan School of Public Health, too much sodium wreaks havoc on the kidneys and heart and forces the body to hold onto water to dilute the excess sodium. 
A combination of the amount of fluid surrounding cells and the volume of blood in the bloodstream forces the heart to work harder and puts increased pressure on blood vessels. Over time, this can lead to stiffening of blood vessels, resulting in hypertension, heart attack, and stroke.
Now, there is evidence to suggest that the type of salt a person consumes is more important than the amount they consume. Industrially-refined salt lacks the minerals the body needs to properly function, and that’s the kind of salt that gets dumped into processed foods.
Unrefined sea salt provides many health benefits that we’ve covered in the past. But you must make sure it is unrefined.
Furthermore, there are scientists who believe that the over-consumption of sodium is not the true cause of high blood pressure.