We’ve all been told that a high-salt diet is a leading cause of high blood pressure (hypertension), heart attack, stroke and heart failure. What doctors don’t tell patients—what many doctors don’t know themselves—is that salt doesn’t have the same effect on everyone’s blood pressure.
A surprising fact: Many people do better when they consume more than the USDA’s recommended daily sodium limit of 2,300 mg (roughly the amount in one teaspoon of salt). Other common misconceptions regarding sodium…
Myth #1: Salt raises blood pressure in everyone. It’s true that doctors have a right to worry about the salt consumption for some patients. Salt sensitivity—generally defined as an increase of 5% or more in blood pressure when sodium is consumed—is most common in older adults, black people and people of Chinese descent. Important: If you’re sensitive to salt, exceeding the recommended daily limit of 2,300 mg of sodium can cause sharp rises in blood pressure.
But what’s harmful for this subset of the population is not harmful for everyone. Research shows that salt sensitivity affects about half of people with high blood pressure and about 20% of people who have normal blood pressure.
Myth #2: Salt always increases heart disease. If a high-salt diet increased blood pressure, it would obviously increase the risk for cardiovascular disease—but, as discussed earlier, this occurs only in some people. When researchers study whether eating highly salted foods increases the rates of high blood pressure and heart disease, the findings are mixed. Meanwhile, the correlation between high-salt diets and improved health is compelling.
Example: People consume staggering amounts of sodium in Japan, France and South Korea. The average South Korean, for example, consumes more than 4,000 mg of sodium a day. In France and other Mediterranean countries, very salty foods, such as prepared sardines, anchovies and many aged cheeses, are eaten with most meals. Yet these countries are among those with the lowest death rates from coronary heart disease in the world, and Japan and South Korea boast among the highest longevity.
Most people don’t realize that a low-salt diet can sometimes raise blood pressure by stimulating the body’s “rescue” system (the renin-angiotensin aldosterone system) that’s designed to help the body retain salt and water. When this occurs, low salt intake can increase heart rate, blood clotting and the constriction of blood vessels. It’s also been linked to insulin resistance and diabetes.
Myth #3: No one needs more salt. The ubiquitous advice to reduce sodium intake might be justified if it helped some people and didn’t hurt the rest. But this isn’t always the case.
To remain in homeostasis, the physiological state that puts the least stress on the body, most people who are not salt sensitive need about 3,000 mg to 5,000 mg of sodium a day.
What’s more, many of our food choices (sugar and caffeinated beverages, for example) deplete salt from the body. So do commonly prescribed medications such as some antidepressants, diuretics and diabetes drugs. In addition, the average nonathletic adult sweats out 600 mg of sodium a day.
Myth #4: Healthy diets are naturally low in salt. The diets that experts recommend for disease prevention, such as the Mediterranean diet, do exclude many of the processed foods that happen to be high in salt (and other unhealthful ingredients)—but they’re not low-salt diets overall. If anything, as mentioned above with such countries as Japan and South Korea, they contain more salt than Americans typically eat. Think seafood (clams, lobster, crab), olives, kimchi, etc.
Why do these countries have less cardiovascular disease than the US? While there is no definitive research that a high-salt diet is the reason, it’s been my observation that people who indulge their salt cravings tend to eat more heart-healthy vegetables (particularly the bitter ones, such as bitter greens)…nuts…and seeds—most likely because these healthy foods taste better with salt.
What’s more, there is often a lot of potassium in naturally salty foods—for example, spinach, Swiss chard and artichokes. When it comes to improving blood pressure and heart health, more potassium is probably more important than less sodium.
Myth #5: Everyone should check the sodium content on food labels. Unless you eat a lot of pretzels, chips and other super-salty foods, you are unlikely to eat more salt than your body can handle—unless you’re salt-sensitive (see below).
I do advise people to avoid processed foods—mainly because these foods tend to be high in sugar, which can increase the risk for high blood pressure, diabetes and obesity. Most processed foods also lack fiber, and a lack of fiber can cause sugar spikes. It’s much better to indulge your salt cravings with foods that are naturally salty—for example, sea vegetables (kelp, seaweed and algae), seafood, cheese and olives.
Are You Salt-Sensitive?
There are no readily available tests to determine whether a person is salt-sensitive. So how do you know whether a low-salt diet would help you or hurt you?
Try this: With your doctor’s OK, for two weeks, reduce your sodium intake to less than 2,300 mg of sodium per day. If your blood pressure drops by 5% or more, chances are you are salt-sensitive. If your blood pressure does drop, be alert for dizziness, fatigue, nausea, muscle spasms/cramps and blurred vision—signs that your blood pressure may be too low. In these cases, you may be better off listening to your body’s salt cravings and eating the salt that it demands rather than adhering to a strict low-sodium diet. Important: Discuss this with your doctor, and monitor your blood pressure closely.