High blood pressure: is salt the only culprit?
High blood pressure is often linked to eating too much salt. The connection is well established scientifically, but salt is not the only factor. Blood pressure is shaped all at once by body weight, physical activity, nutrition, alcohol, sleep, stress, genetics, kidney function, medications and metabolic health.
That is why cutting out salt alone may not bring your blood pressure back to normal. At the same time, it would be a mistake to conclude that the amount of salt doesn’t matter, or that someone with high blood pressure can safely drink salt water.
Sodium affects blood pressure even if you aren’t salt-sensitive
Table salt consists mainly of sodium chloride. Sodium is essential for the body: it helps maintain fluid balance and plays a role in nerve and muscle function. With a modern diet, the problem is usually not a lack of sodium but too much of it – especially from ready meals, processed meats, cheese, bread, sauces, snacks and fast food.
Reducing sodium lowers blood pressure on average across the whole population, but the size of the effect differs from person to person. Studies suggest that salt sensitivity may occur in roughly:
- 25–30 percent of people with normal blood pressure;
- about half of people with hypertension.
Salt sensitivity is more common in older age and in people with excess weight, diabetes, metabolic syndrome and kidney disease. It can’t be reliably identified with a routine blood test, so in practice the effect of salt is usually assessed from your diet and repeated blood pressure measurements. Salt sensitivity does not, however, mean that everyone else can consume unlimited sodium.
The World Health Organization recommends that adults stay under 2000 milligrams of sodium a day, which corresponds to roughly five grams of salt, or slightly less than one teaspoon. You need to count all the salt you get from food, not just what is added during cooking. The same recommendation of under 2 grams of sodium a day is included in the 2024 European hypertension guidelines. (WHO, European Society of Cardiology)
Should you add salt to your morning drinking water?
For a healthy person who eats normally and hasn’t lost a lot of fluid, there is no evidence-based need to add salt to morning water. A night without food or drink doesn’t automatically mean a significant fluid or sodium deficit. Salt doesn’t “direct water to the right place” – the distribution of fluid and electrolytes is regulated by the kidneys, hormones and cell membranes.
Celtic, Himalayan and sea salt are also not significantly better than regular salt when it comes to blood pressure. Their mineral content is small, and the main component is still sodium chloride.
Extra sodium may be justified in exceptional situations, for example:
- during long, intense endurance training;
- when sweating very heavily;
- in a hot climate or during prolonged physical work;
- during an illness involving fluid loss;
- when a doctor has diagnosed sodium deficiency.
Even then, the need depends on the length of the workout, how much you sweat, the weather and your health status. For a typical shorter strength or fitness workout, water and your usual food are generally enough. Electrolyte needs are individual, and taking too much does not automatically improve fluid balance. (American Heart Association)
If you have high blood pressure, heart failure or kidney disease, regularly drinking salt water without a healthcare professional’s recommendation is not advisable.
Insulin resistance and high blood pressure
With insulin resistance, the body’s cells don’t respond to insulin effectively enough, and the body produces more insulin to keep blood sugar under control. This can be accompanied by:
- greater retention of sodium and fluid in the kidneys;
- increased activity of the sympathetic nervous system;
- impaired blood vessel function;
- excess weight and chronic low-grade inflammation.
These changes can contribute to the development of high blood pressure and increase salt sensitivity. Research has found a link between insulin resistance and salt sensitivity, but this does not prove that insulin resistance is the only cause of high blood pressure for most people. (Scientific review)
Nor can the problem be reduced to the claim of “too many carbohydrates”. What matters more is the quality of the carbohydrates, how much you eat, your body weight and your overall menu. Whole grains, legumes, vegetables, berries and fruit can all be part of a diet that supports healthy blood pressure. What is worth cutting back on is, above all, sugary drinks, sweets, refined grain products and excess energy intake.
Losing body weight if needed, regular aerobic and strength training, enough sleep and a 10–15-minute walk after eating can all help improve insulin sensitivity. A supplement should not be seen as a substitute for these measures or for treatment prescribed by a doctor.
Potassium helps balance the effects of sodium
Potassium supports the normal function of blood vessels and promotes the excretion of sodium through the kidneys. When it comes to high blood pressure, what matters is not only how much sodium you get, but also the balance between sodium and potassium.
The WHO recommends that adults get at least 3510 milligrams of potassium a day from food. Good sources of potassium include:
- potatoes and sweet potatoes;
- beans, peas and lentils;
- tomatoes and green vegetables;
- bananas, citrus fruits and other fruits;
- avocado;
- plain yogurt and other dairy products;
- fish;
- nuts and seeds.
The safest way to increase your potassium intake is through a varied diet. A diet richer in potassium and less processed usually also provides more dietary fiber, magnesium and other nutrients that are good for the heart. (WHO potassium recommendation)
Potassium supplements are not for everyone
A potassium supplement is not the usual first choice for treating high blood pressure on its own. Too much potassium can cause hyperkalemia and dangerous heart rhythm disorders.
People who need to be especially careful include those with:
- kidney disease or reduced kidney function;
- heart failure;
- kidney damage caused by diabetes;
- a history of high potassium levels;
- use of an ACE inhibitor, an angiotensin receptor blocker, a potassium-sparing diuretic or another medication that affects potassium levels.
In such cases, the use of potassium supplements and potassium-enriched salt must be agreed with a doctor.
How is potassium level measured?
Although most of the body’s potassium is found inside cells, in clinical practice potassium level is measured mainly from blood serum or plasma. This is the standard test used to assess a potassium deficiency or excess that is dangerous to the heart and muscles.
Mineral analysis of erythrocytes, or red blood cells, is not a standard method for assessing the body’s “potassium reserves”, and it is generally not necessary in the case of high blood pressure. No potassium test directly shows whether a person has been eating enough potassium-rich foods over a longer period. The result has to be interpreted together with kidney function, medications, symptoms and other tests. (MedlinePlus, Johns Hopkins Medicine)
What actually helps lower blood pressure?
An evidence-based approach involves several steps taken at the same time:
- Measure your blood pressure correctly at home and keep a log of the results.
- Cut back on ready meals, processed meat products, salty snacks and sauces.
- Eat more vegetables, fruit, legumes and other natural sources of potassium.
- Be physically active regularly and combine aerobic and strength training.
- If you are overweight, lose body weight – even moderate weight loss can improve blood pressure.
- Limit alcohol and quit smoking.
- Take care of your sleep and, if needed, get checked for sleep apnea.
- Work with your doctor to check your blood sugar, blood fat levels, kidney function and the medications you take.
- Take prescribed blood pressure medication consistently and don’t change your treatment on your own.
Summary
Salt is not the only cause of high blood pressure, but its role should not be downplayed. Salt-sensitive people react particularly strongly to sodium, and they make up roughly half of all patients with hypertension.
What helps most is not fearing salt or promoting salt water, but improving the whole picture: less processed food high in sodium, more potassium-rich foods, regular physical activity, a healthy body weight, good sleep, moderate alcohol consumption and, where needed, medical treatment.
Persistently high blood pressure should not be treated with diet, salt, a potassium supplement or a blood sugar–affecting supplement alone. If the average of your home measurements is approximately 135/85 mmHg or higher, it is worth contacting your family doctor. Prescribed blood pressure treatment must not be stopped on your own because of changes in nutrition.
This article is for general information only and does not replace the advice of a doctor or another qualified healthcare professional.
