6 Little-Known Dangers of Restricting Sodium Too Much
Medically reviewed by Atli Arnarson BSc, PhD — By Hrefna Palsdottir, MS on February 27, 2020
This article discusses sodium restriction in the general population. If you have been prescribed a low-sodium diet by your healthcare professional, or need to adhere to a low-sodium diet to manage a condition, the following information may not apply to you.
Sodium is an important electrolyte and main component of table salt.
Too much sodium has been linked to high blood pressure, and health organizations recommend that you limit your intake (1Trusted Source, 2Trusted Source, 3Trusted Source).
Most current guidelines recommend eating less than 2,300 mg per day. Some even go as low as 1,500 mg per day (4Trusted Source).
However, even though too much sodium causes problems, eating too little can be just as unhealthy.
Here are 6 little-known dangers of restricting sodium too much
- May increase in insulin resistance
A few studies have linked low sodium diets to increased insulin resistance (5Trusted Source, 6Trusted Source, 7Trusted Source).
Insulin resistance is when your body’s cells don’t respond well to signals from the hormone insulin, leading to higher insulin and blood sugar levels.
Insulin resistance is believed to be a major driver of many serious diseases, including type 2 diabetes and heart disease (8Trusted Source, 9Trusted Source).
One study involving 152 healthy people found that insulin resistance increased after only 7 days on a low sodium diet (5Trusted Source).
Yet, not all studies agree. Some have found no effect, or even a decrease in insulin resistance (10Trusted Source, 11Trusted Source, 12Trusted Source).
However, these studies varied in length, study population, and degree of salt restriction, which may explain the inconsistent results.
Low sodium diets have been associated with increased insulin resistance, a condition that causes higher blood sugar and insulin levels. This may lead to type 2 diabetes and other serious diseases.
- No clear benefit for heart disease
It’s true that reducing your sodium intake can reduce your blood pressure.
However, blood pressure is only a risk factor for disease. What’s really significant is hard endpoints like heart attacks or death.
Several observational studies have looked at the effects of low sodium diets on heart attacks, strokes, and the risk of death (13Trusted Source, 14Trusted Source, 15Trusted Source).
One study found that less than 3,000 mg of sodium per day is linked to an increased risk of dying from heart disease, including heart attacks and strokes (14Trusted Source).
Disturbingly, another study reported a higher risk of dying from heart disease at the lower sodium levels that many guidelines currently recommend (15Trusted Source).
However, other studies have reported conflicting results, so this matter is far from settled (16Trusted Source, 17Trusted Source, 18Trusted Source).
In a 2011 review, reducing sodium didn’t reduce the risk of dying from heart attacks or strokes, and it increased the risk of death from heart failure (19Trusted Source).
Although the evidence is mixed, some observational studies show that low salt diets are linked to an increased risk of death from heart attacks or strokes. Controlled trials show no clear benefit.
- Increased risk of death from heart failure
Heart failure is when the heart is not able to pump enough blood around the body to meet its needs for blood and oxygen.
This doesn’t mean that your heart stops working completely, but it’s still a very serious health issue.
Interestingly, low sodium diets have been linked to an increased risk of death in people with heart failure.
One review found that for people with heart failure, limiting sodium intake increased the risk of dying (19Trusted Source).
In fact, the effect was strong — people who restricted their sodium intake had a 160% higher risk of death. This is concerning, as people with heart failure are often told to limit their sodium intake.
Yet, the results were strongly influenced by only one study, so more research is needed.
There’s some evidence that people with heart failure may have a higher risk of dying on a low sodium diet. However, more studies are needed to confirm this.
- May raise LDL (bad) cholesterol and triglycerides
Many factors can increase the risk of heart disease, including elevated LDL (bad) cholesterol and triglycerides.
Some studies have found that low sodium diets may increase both LDL (bad) cholesterol and triglyceride levels.
In a 2003 review of studies in healthy people, low sodium diets caused a 4.6% increase in LDL (bad) cholesterol and a 5.9% increase in triglycerides (20Trusted Source).
A more recent review reported a 2.5% increase in cholesterol and a 7% increase in triglycerides (21Trusted Source).
What’s more, these studies found that salt restriction only caused minor reductions in blood pressure, on average, with a slightly stronger effect in people with high blood pressure.
Studies have found that limiting salt may raise LDL (bad) cholesterol and triglycerides, which are common risk factors for heart disease.
- Increased risk of death for people with diabetes
People with diabetes have an increased risk of heart attack and stroke (22Trusted Source).
Therefore, many guidelines for those with diabetes recommend limiting salt intake (23Trusted Source, 24Trusted Source).
However, some studies have found an association between low sodium intake and an increased risk of death among those with both type 1 and type 2 diabetes (25Trusted Source, 26Trusted Source).
However, these were observational studies, and their results should be interpreted with caution.
People with type 1 and type 2 diabetes may have an increased risk of death on a low sodium diet. However, this needs to be studied further.
- Higher risk of hyponatremia (low blood levels of sodium)
Hyponatremia is a condition characterized by low levels of sodium in the blood.
Its symptoms are similar to those caused by dehydration. In severe cases, the brain may swell, which can lead to headaches, seizures, coma, and even death (27Trusted Source).
Certain populations, like older adults, have a higher risk of hyponatremia (28Trusted Source).
That’s because older adults are more likely to have an illness or take medication that can reduce sodium levels in the blood.
Athletes, especially those who participate in long-distance endurance events, are also at a high risk of developing exercise-associated hyponatremia (29Trusted Source, 30Trusted Source).
In their case, it’s usually caused by drinking too much water and failing to replace the sodium that’s lost through sweat (31Trusted Source).
A condition called hyponatremia, or low blood sodium levels, may affect certain people like older adults and some athletes. Eating less salt raises the risk of this condition.
The bottom line
The National Academy of Medicine (NAM) recommends a sodium intake of less than 2,300 mg per day, corresponding to 5.8 grams of salt.
Studies suggest that there’s a J-shaped curve when it comes to the effects of sodium.
Too much may be harmful, but too little can also have serious consequences.
The lowest risk of health issues and death seems to be somewhere in between.
Controversially, some researchers have suggested an intake of 3,000–5,000 mg of sodium per day is considered optimal.
This exceeds the maximum daily intake recommended by NAM, but it’s similar to what the average person already eats in the United States (32Trusted Source, 33Trusted Source).
This amounts to 7.5–12.5 grams of table salt per day, which equals 1.5–2.5 teaspoons per day (salt is only 40% sodium, so multiply sodium by 2.5 to find the amount of salt).
However, many people may benefit from restricted sodium intake, such as those with salt-sensitive high blood pressure (34Trusted Source).
If you have a medical condition that requires a diet low in sodium, or if your healthcare provider has advised you to limit your intake, by all means, continue to do so.
However, if you’re a healthy person trying to stay healthy, there’s no good evidence that following a low sodium diet will improve your health.
Most of the excess sodium people eat comes from processed, packaged foods — stuff you shouldn’t be eating much of anyway.
Adding some salt to your healthy foods to improve their flavor is both safe and healthy — and can make your diet much more pleasurable.
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