Sodium & BP

Results of a crossover trial were recently published in JAMA Open Network, evaluating the effects of both a high and low-sodium diet on blood pressure (BP) within the same individuals. Two hundred and thirteen participants consumed (prospectively) a high sodium (2.2 g sodium added to their usual diet) or a low sodium (500 mg total sodium) diet, each for 1 week. Aged 50 to 75 years (median of 61, 65% female and 64% black), a roughly equal number of study participants had either normal blood pressure or either controlled, uncontrolled, or untreated hypertension at baseline.

The median systolic BP while consuming the usual diet was 125 mmHg, 126 mmHg and 119 mmHg while on the high and low sodium diets, respectively. A mean drop of 4 mmHg in mean arterial pressure (MAP) from the high to low-sodium diet was observed within the same individuals, regardless of baseline BP, and 73.4% of individuals had a decline in MAP while on the low-sodium diet. The mean systolic BP difference was 8 mmHg after a week on the high vs. low sodium diet, and 46% were classified as “salt-sensitive,” indicating a MAP drop of 5 mmHg or more, with similar effects observed across race, sex, BP status, age, and BMI.

This study suggests that the majority of people are likely to have a lower BP while minimizing sodium intake, especially when compared to a high-sodium diet. The reduction in BP is comparable to some first-line anti-hypertensives, particularly when considering the fairly low baseline BP of this population, i.e., a greater effect may have been observed among a population with a higher average BP. For context, a 5 mmHg reduction in systolic BP is associated with a 10% reduction of cardiovascular events among people with and without hypertension.