With heart disease being the number one cause of death in America, reducing risk for CVD is a major concern among health professionals. One of the current recommendations is to reduce sodium intake as increased sodium intake, as increased sodium has a positive correlation with blood pressure, and hypertension is a leading risk factor for CVD. Mary (Molly) Cogswell discusses sodium in a seminar titled “sodium intake assessment, monitoring, and applied research”.
The first thing Dr. Cogswell discussed is where to find sodium. We can’t make recommendations if we don’t know where the problem is. First, while a bulk of sodium comes from table salt (NaCl), there are still other dietary sources of sodium, such as baking soda (NaHCO3). Second, while many recommendations suggest seasoning with less salt, in actuality, that will do very little. Seasoning while cooking and at the table only account for 11% of sodium intake. Pre-processed and restaurant foods account for 71% of sodium intake. This means the biggest way to reduce sodium intake is to change the US food supply. The institute of medicine recommends setting national policies to gradually reduce to sodium used in commercial foods. A similar policy in the UK led to a 42% decrease in ischemic heart disease and a 15% decrease in sodium intake.
The second thing Dr. Cogswell discussed was how to assess and monitor sodium. Accurate measurements are needed in a clinical setting, and especially a research setting, where a small error could be the difference in statistical significance. However, the problem with clinical sodium assessment is, the more accurate a test, the more it costs, which becomes a barrier to many facilities. For example, the 24-hour urinary excretion is the gold standard for sodium assessment. All voided urine over 24 hours is collected and analyzed. This is very labor intensive and time consuming, leading to its high costs. This test still has random measurement error though, since sodium intake and excretion vary day to day. To make it more accurate, the measurement from multiple days would need to be averaged together, which exponentially increases the cost. To make it cheaper, a predicted 24-hour urinary excretion could be conducted. A single sample of urine is taken and used to predict the daily sodium excretion. This is much less accurate, since sodium excretion changes through-out the day, especially at night when the samples are usually taken for convenience. Finding a balance between cost and accuracy is key.
With sodium being such an important factor in reducing CVD risk, it’s necessary to create appropriate recommendations and assessment tools that will help in this endeavor.