Lowering salt is common dietary advice but doing so could actually increase blood pressure and diabetes risk.
Conventional wisdom on salt is that most Americans need to reduce their salt intake; this is the view put forth by the federal government’s Dietary Guidelines for Americans as well as others. The truth is more complicated, particularly with the most up-to-date science. We will untangle some of these threads below, but the main takeaway is one that is common throughout integrative medicine: the healthy way to incorporate salt into your diet is dependent on your own individual biology and needs—there isn’t a one-size-fits-all solution.
The advice for most people to reduce salt is based on the notion that a reduction in salt decreases blood pressure and incidence of hypertension, which in turn leads to a reduction in mortality from cardiovascular disease.
But there is reason to be skeptical of such broad claims. For one, the results of the largest trial to date looking at salt reduction and incidence of heart failure were released earlier this month. The trial found that reducing salt intake did not lead to fewer emergency room visits, hospitalizations, or deaths for patients with heart failure.
The truth is that salt affects people differently. Some people can eat salt with no effect on their blood pressure; other people are “salt sensitive” and even a slight increase in sodium intake can increase blood pressure and harm the kidneys’ ability to regulate fluid.
This is why integrative practitioners often tell us to be wary of “low salt diets.” Lowering salt intake may be appropriate for some “salt sensitive” individuals to lower blood pressure. But for others with normal blood pressure, some evidence demonstrates that lowering salt intake is just as likely to increase blood pressure as to reduce it. And even if cutting salt reduces blood pressure, it may not be a good thing, because it activates salt-retaining hormones which can stiffen arteries. Animal studies have shown that low salt diets can accelerate atherosclerosis. Low salt diets can also elevate insulin levels, meaning lowering salt may increase your risk of becoming overweight or obese (insulin is a fat-storing hormone).
Additionally, not all salt is created equal. Most of the salt people eat tends to come from ultra-processed junk foods that contain refined salt. These foods should be eaten sparingly, if at all. Refined salt has been chemically treated to improve the product’s shelf life; chemicals are added that contain anti-caking, free flowing, or conditioning agents, such as sodium ferrocyanide, ammonium citrate, and aluminum silicate. Unrefined salt, like sea salt, contains over 80 natural minerals and elements that have myriad health benefits.
The campaign to reduce excess salt intake may have had the unintended consequence of making many of us iodine insufficient or deficient. Typical Western diets are low in iodine, so table salt was iodized decades ago to prevent goiters. Iodine is essential for thyroid function, and inadequate iodine has also been linked to cancers, fatigue, and weight gain. Note that you can get sufficient iodine from your diet by eating foods like fish and seaweed.
The main point is, like most health issues, there is no one, simple answer. We all need to assess our own health to determine what level of salt intake is appropriate.