Medical Compass: It’s not really about the salt shaker

Sodium’s effects are insidious

By David Dunaief, M.D.

Most of us consume far too much sodium. Americans consume an average of 3400 mg per day, well over the recommended 2300 mg per day recommended upper limit for those who are 14 and over (1). These consumption numbers are even higher for some demographics. It’s become such a health problem that the FDA is getting involved, working with food manufacturers and restaurants to drive these numbers down (2). 

Why all the concern? Because even if we don’t have hypertension, sodium can have a dramatic impact on our health.

Sodium is everywhere, including in foods that don’t taste salty. Bread products are among the worst offenders. Other foods with substantial amounts of sodium include cold cuts and cured meats, cheeses, pizza, poultry, soups, pastas, sauces and, of course, snack foods. Packaged foods and those prepared by restaurants are where most of our consumption occurs.

On the flip side, only about two percent of people get enough potassium from their diets (3). According to the National Institutes of Health, adequate intake of potassium is between 2600 mg and 3400 mg for adult women and men, respectively.

What is the relationship between sodium and potassium?

A high sodium-to-potassium ratio increases our risk of cardiovascular disease by 46 percent, according to a 15-year study of more than 12,000 (4). To improve our overall health, we need to shift the sodium-to-potassium balance so that we consume more potassium and less sodium. And if you struggle with – or are at risk for – high blood pressure, this approach could help you win the battle.

Why lower your sodium consumption?

Two studies illustrate the benefits of reducing sodium in high blood pressure and normotensive (normal blood pressure) patients, ultimately preventing cardiovascular disease, including heart disease and stroke.

The first was a meta-analysis that evaluated data from 34 randomized clinical trials, totaling more than 3,200 participants. It demonstrated that salt reduction from 9-to-12 grams per day to 5-to-6 grams per day had a dramatic effect. Blood pressure was reduced by a significant mean of −4.18 mm Hg systolic (top number) and −2.06 mm Hg diastolic (bottom number) involving both normotensive and hypertensive participants (5). 

When looking solely at hypertensive patients, the reduction was even greater, with a systolic blood pressure reduction of −5.39 mm Hg and a diastolic reduction of −2.82 mm Hg. The researchers believe that the more we reduce the salt intake, the greater the effect of reducing blood pressure. The authors recommend further reduction to 3 grams per day as a long-term target for the population and concluded that the effects on blood pressure will most likely result in a decrease in cardiovascular disease.

In the second study, a meta-analysis of 42 clinical trials including both adults and children, there was a similarly significant reduction in both systolic and diastolic blood pressures (6). Both demographics saw a blood pressure reduction, although the effect was greater in adults. Interestingly, an increase in sodium caused a 24 percent increased risk of stroke incidence but, more importantly, a 63 percent increased risk of stroke mortality. The risk of mortality from heart disease was increased alongside an increase in sodium, as well, by 32 percent.

Can you consume too little sodium?

Some experts warn that too-low sodium levels can be a problem. While this is true, it’s very rare, unless you take medication or have a health condition that depletes sodium. We hide sodium everywhere, so even if you don’t use a salt shaker, you’re probably consuming more than the recommended amount of sodium.

Why is potassium consumption important?

In a meta-analysis involving 32 studies, results showed that as the amount of potassium was increased, systolic blood pressure decreased significantly (7). When foods containing 3.5 to 4.7 grams of potassium were consumed, there was an impressive −7.16 mm Hg reduction in systolic blood pressure with high blood pressure patients. Anything more than this amount of potassium did not provide additional benefit. Increased potassium intake also reduced the risk of stroke by 24 percent.

Blood pressure reduction was greater with increased potassium consumption than with sodium restriction, although this was not a head-to-head comparison. The good news is that it’s easy to increase your potassium intake; it’s found in many whole foods and is richest in fruits, vegetables, beans and legumes.

The bottom line: decrease your sodium intake and increase potassium intake from foods. First, consume less sodium, and give yourself a brief period to adapt — it takes about six weeks to retrain your taste buds. You can also improve your odds by increasing your dietary potassium intake, striking a better sodium-to-potassium balance.

References:

(1) Dietary Reference Intakes for Sodium and Potassium. Washington (DC): National Academies Press (US); 2019 Mar. (2) fda.gov. (3) nih.gov. (4) Arch Intern Med. 2011;171(13):1183-1191. (5) BMJ. 2013 Apr 3;346:f1325. (6) BMJ. 2013 Apr 3;346:f1326. (7) BMJ. 2013; 346:f1378.

Dr. David Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.