A large number of research results show:High sodium intake may lead to high blood pressure; High blood pressure is a risk factor for some acute or chronic diseases (such as stroke), so the intake is gradually restricted. According to the latest healthy eating guidelines in the United States, the recommended upper limit of daily sodium intake is 2,300 mg, which is approximately the sodium content of 6 g of salt (for details, seethis article).
But new research recently published in heavyweight journals may cause experts to recalibrate this advice! This article was newly published in "JAMA network" in 2023paper, whose research team explored in detail the impact of dietary sodium intake on blood pressure in middle-aged and elderly people. The research team included 213 subjects aged 50 to 75 years old from two cities in the United States from 2021 to 2023 (about 25% has normal blood pressure, 20% has normal blood pressure controlled by medication, and 30% has poor blood pressure control with medication. Hypertensive patients, and 25% uncontrolled hypertensive patients), the team subsequently arranged for the subjects to receive a high-sodium diet for one week (an additional 2,200 mg of sodium was added to the original diet) and a low-sodium diet for one week (total sodium per day). The intake amount is only 500 mg), which is a crossover trial study.
The results of the study show that in terms of self-subject changes, blood pressure on a high-sodium diet is about 4 mmHg higher on average than on a low-sodium diet, while in terms of inter-individual changes,Blood pressure was on average about 8 mmHg higher on a high-sodium diet than on a low-sodium diet.! andSuch differences also exist in subgroup analysis(sub-groups: age, sex, race, hypertension, baseline BP, diabetes, and body mass index)! In addition, there are no serious side effects whether it is a high-sodium diet or a low-sodium diet.
In conclusion,In middle-aged and elderly people, the effect of low-sodium diet on lowering blood pressure is significant, and the time required for the intervention to produce effects is not long, and similar effects are also found in different subgroups., In addition, a low-sodium diet has no serious side effects and is indeed a highly recommended non-drug way to lower blood pressure.
The author would like to point out one point in particular:The low-sodium diet in this study is really low! The total daily sodium intake is 500 mg. After conversion: 500 mg x (58.5/23) = 1,271 mg, which is equivalent to only about 1.27 g of table salt! It means that we may not really need so much sodium intake. Therefore, this study may change experts’ thinking about the recommended amount of sodium intake. Of course, the human body does not completely need sodium, but after more research data appears in the future, perhaps our recommended amount of sodium intake will be revised downwards. Not necessarily!
〈The author is former Attending Physician in National Taiwan University Hospital, and Master of Science from National Taiwan University〉