Salt and blood pressure: how much does cutting back really help?

Salt and blood pressure: nearly every Dutch advice page stops at "no more than 6 grams a day". What they rarely add is what cutting back buys you. In a Cochrane review of 34 trials, systolic pressure fell by an average of 4.2 mmHg on 4.4 grams less salt per day (He, 2013).

So it is no miracle fix. It is not nothing either, especially if your blood pressure already sits on the high side.

What strikes me most in conversations with men: everyone pictures the salt shaker. Meanwhile most of it is already in your bread, your cheese and your pasta sauce.

Why does salt raise your blood pressure?

Salt is sodium chloride, and sodium pulls water with it. Eat a lot of salt and your body holds on to more fluid for a while, so your blood volume rises. More volume in the same set of vessels means more pressure. Your kidneys clear the surplus, but in some people that goes slower.

Your fluid balance is the link between your plate and your systolic number. Your kidneys manage that around the clock.

Salt also appears to act on the vessels themselves. Research points to effects on the vessel wall and on hormones that regulate blood pressure (Elijovich, 2016).

It is not a simple tap, but the direction holds up.

Salt and blood pressure: how many mmHg does cutting back buy?

On average roughly 4 mmHg off your systolic and 2 mmHg off your diastolic pressure, on 4.4 grams less salt per day. That comes from a Cochrane review of 34 trials with 3,230 participants (He, 2013). In people with high blood pressure the drop was larger than in people with normal readings.

Put that next to the other levers. Losing a few kilos or quitting smoking often does more. Less salt is one of the levers, not the only one.

Then the part almost nobody prints. That average hides big differences between people.

Some people react strongly to salt, others barely at all. It is called salt sensitivity. In Weinberger's work, roughly half of the people with high blood pressure responded clearly to a salt load, against roughly a quarter of those with normal blood pressure (Weinberger, 1996).

In a long follow-up, salt sensitivity was linked to a higher risk of death, including in people without high blood pressure (Weinberger, 2002). That is an observation, not proof of cause and effect.

So you cannot know in advance whether you are a strong or a weak responder.

How much salt per day is too much?

The Voedingscentrum, the Dutch nutrition body, advises adults to stay under 6 grams of salt a day, roughly 2.4 grams of sodium. The WHO works with 5 grams. Dutch men sit well above that: in RIVM measurements using 24-hour urine, the median for men was around 11 grams a day.

That gap between advice and practice is wider than food diaries suggest. Questionnaire-based estimates put men around 7.8 grams a day (Voedingscentrum). Urine puts them much higher.

The reason is plain. People underestimate what sits in ready-made products, and urine does not lie.

I think that urine figure is the most honest number we have. A food diary mostly measures what you remember.

Hidden salt: an ordinary Dutch day, added up

Almost nobody reaches 10 grams of salt through the shaker. It hides in products you do not taste as salty. Below are rough per-portion figures, the kind you find on labels of everyday Dutch products.

Those last two rows get forgotten. Anyone training seriously eats protein bars and drinks sports products with sodium in them. It all counts.

Take Mark, 38, in the gym three times a week. Breakfast: two slices of bread with cheese, 1.2 grams. Lunch: three slices with ham and cheese, 2.0 grams. After training a shake and a bar, 0.6 grams. Dinner: pasta with jarred sauce and grated cheese, 1.9 grams. In the evening a handful of salted nuts, 0.6 grams.

That is 6.3 grams. Mark never touched the salt shaker and is already over the Voedingscentrum advice.

Stir a stock cube into that sauce and he lands around 11 grams.

Bread, cheese and cold cuts are the biggest sources in the Netherlands. Not because they are the saltiest, but because we eat so much of them (Voedingscentrum).

How quickly do you notice the effect of less salt?

Your fluid balance adjusts within days, but your blood pressure needs longer. In the trials the Cochrane review included, salt reduction ran for at least four weeks before the effect could be measured reliably (He, 2013). So count in weeks, not days.

In the first days you mostly see your weight and fluid retention shift. That is not a blood pressure gain, that is water.

If you want to track it yourself, a single reading says little. Many people take readings across several days, around the same time each day. How to set that up is in measuring blood pressure at home.

See nothing after four weeks and that is information too. You may simply not be very salt sensitive.

Does your blood sodium value say anything about your salt intake?

No, not really. Your blood sodium value is tightly regulated and mostly reflects your water balance. The American Dietary Reference Intakes put it plainly: blood sodium concentration is not a reliable indicator of usual dietary sodium intake (NASEM, 2019).

This is the misconception I run into most often. Someone sees sodium 141 mmol/l on a result, thinks "fine, I do not eat too much salt", and reads on.

That is not how it works. Your body keeps blood sodium inside a narrow band, mainly by shifting water around. Eat more salt and you get thirsty, and your kidneys clear the surplus.

The concentration stays roughly the same, even if your intake doubles.

An abnormal sodium value usually points to a water problem rather than a salt problem. Think heavy drinking of fluids, fluid loss, or medication that affects water handling (Sterns, 2015).

What does move with your intake is sodium in your urine over 24 hours. That is the measurement RIVM uses, and it is exactly why those figures land higher than food diaries.

Your kidneys do that work. How well they do it shows up sooner in eGFR and creatinine than in your sodium. Some men have those values measured once with a kidney function test.

Is potassium salt a good alternative?

Potassium salt swaps part of the sodium chloride for potassium chloride. It tastes salty, but delivers less sodium and more potassium. In a large trial among nearly 21,000 people with a history of stroke or high blood pressure, strokes were lower in the salt substitute group (Neal, 2021).

The difference came to roughly 14 percent fewer strokes over almost five years. A solid result, though in a group with high baseline risk and a high salt intake.

Whether that transfers one to one to a healthy Dutch man of 35, we do not know.

There is a catch as well. Extra potassium is not harmless for everyone. With reduced kidney function, or on certain blood pressure medication, potassium can build up.

If you take blood pressure medication, talk to your GP before switching to potassium salt.

My honest view: potassium salt is a decent tool, but it does not fix your pasta sauce.

What to look at tomorrow

The gain is not in the shaker. It is in four categories from the table: bread, cheese, cold cuts and jarred sauces. Labels list salt per 100 grams, so holding two jars side by side costs you ten seconds.

Stress plays a part in your blood pressure too, though not the way most men assume. We wrote about that in stress and blood pressure.

If you want the wider picture, start at high blood pressure in men.

If your readings stay high across several weeks, that is worth a conversation with your GP. Bring your measurements, with the date and time next to each one.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

References

1. He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ. 2013;346:f1325. PMID 23558162.
2. Weinberger MH. Salt sensitivity of blood pressure in humans. Hypertension. 1996;27(3 Pt 2):481-490. PMID 8613190.
3. Weinberger MH, et al. Salt sensitivity is associated with an increased mortality in both normal and hypertensive humans. J Clin Hypertens (Greenwich). 2002. PMID 12147930.
4. Elijovich F, et al. Salt sensitivity of blood pressure: a scientific statement from the American Heart Association. Hypertension. 2016;68(3):e7-e46. PMID 27443572.
5. Sterns RH. Disorders of plasma sodium: causes, consequences, and correction. N Engl J Med. 2015;372(1):55-65. PMID 25551526.
6. Neal B, et al. Effect of salt substitution on cardiovascular events and death. N Engl J Med. 2021;385(12):1067-1077. PMID 34459569.
7. National Academies of Sciences, Engineering, and Medicine (NASEM). Dietary Reference Intakes for Sodium and Potassium. 2019.
8. RIVM. Salt and potassium intake, nutritional status research using 24-hour urine. 2020/2021.
9. Voedingscentrum. Zout (salt). Accessed 2026.