Low sodium: the salt shaker isn't the problem. The packet is.
A low sodium diet lowers blood pressure, and the trials are solid. But most of your salt was added in a factory before you ever picked up the shaker. Here's what works, what's oversold, and the salt swap that can be dangerous for some people.
The short version
- What it is
- Eating less sodium, mostly salt, usually under 2 g of sodium (5 g of salt) a day, often prescribed for blood pressure, heart or kidney problems.
- Good for
- Lowering blood pressure, especially if yours is already high.
- Bad at
- Being easy. Bread, sauces, cheese and takeaway food are loaded before you touch them.
- Evidence
- Strong for blood pressure. Less clear for some conditions, like heart failure.
- Our take
- Less salt is good advice for almost everyone. A prescribed limit is your doctor's call, not ours.
What a low sodium diet actually is
Salt is sodium chloride. Sodium is the part that matters for your blood pressure. The World Health Organization recommends adults eat less than 2,000 mg of sodium a day, which is under 5 g of salt, just under a teaspoon. The global average is more than double that.1 The NHS sets the UK adult maximum a little higher, at 6 g of salt a day.2
A low sodium diet in the medical sense is a limit your doctor or dietitian sets for a condition: high blood pressure, heart failure, kidney disease and others. The exact number depends on you. That's the point of a prescription.
Here's the catch. Around three quarters of the salt people eat in the UK is already in packaged and everyday foods, plus takeaways and restaurant meals.2 Throwing away the salt shaker is a nice gesture. It's not the main event.
How it works in your body
Your kidneys keep the sodium level in your blood within a tight range. When you eat a lot of sodium, your body holds on to more water to keep the balance. More fluid in your blood vessels means more pressure on their walls. Over years, raised blood pressure strains your heart, brain, kidneys and arteries. The WHO links high sodium intake to heart disease, stroke and kidney disease, mainly through blood pressure.1
Potassium sits on the other side of the scale. Salt substitutes that swap part of the sodium for potassium lower blood pressure, and the WHO wants potassium to come mainly from foods like beans, peas, nuts and green vegetables.6 That's one reason fruit, vegetables and beans show up in every blood-pressure diet. Hold that thought: for some people, extra potassium is a danger, not a bonus. More below.
What you eat, what you don't
Eat
- Fresh vegetables and fruit, any you like (unless your doctor limits potassium)
- Fresh fish, chicken, eggs, meat you season yourself
- Dried beans, lentils, or tinned ones labelled "no added salt", rinsed
- Oats, brown rice, plain potatoes
- Unsalted nuts and seeds
- Plain yoghurt, milk
- Garlic, ginger, lemon, lime, chilli, herbs, pepper, spices
Forget it
- Cured meats: ham, bacon, salami, Wurst, lap cheong
- Instant noodles and their flavour sachets
- Stock cubes, gravy granules, ready meals
- Soy sauce, fish sauce, oyster sauce, ketchup by the splash
- Salted snacks: crisps, salted nuts, Brezel
- Pickles, olives, salted fish, salted egg anything
- Hard and processed cheese in big amounts
Alcohol on a low sodium diet
If your doctor says it's OK
- A glass of dry wine with a meal
- Spirits with soda water and lime
- Alcohol-free days, plenty of them
Out
- Heavy drinking and binges
- Bar snacks: salted peanuts, crisps, pretzels
- Bloody Marys and other drinks with salted rims or tomato juice
- Sweet cocktails and mixers (sugar is on our never list anyway)
50 Club: not on a prescribed diet. Ask your doctor or dietitian what's safe for you.
Alcohol pushes blood pressure up too. A meta-analysis of 36 trials found that people who drank six or more drinks a day and cut back by about half lowered their systolic blood pressure by about 5.5 mmHg.7 That's in the same range as cutting salt. If your blood pressure is the reason you're on a low sodium diet, drinking less is part of the same job. All the details are in our alcohol guide.
What it's good for, with proof
Lower blood pressure
A Cochrane review in the BMJ pooled 34 trials with 3,230 people who cut salt by about 4.4 g a day. Systolic blood pressure (the top number) fell by about 5.4 mmHg in people with high blood pressure and 2.4 mmHg in people with normal blood pressure.3 Modest change, real effect.
Even better with DASH
In the DASH-Sodium trial, 412 adults ate controlled diets at three sodium levels, 30 days each, on either a typical American diet or the DASH diet (lots of vegetables, fruit and low-fat dairy). Low sodium plus DASH lowered systolic blood pressure by 11.5 mmHg in people with high blood pressure, compared with high sodium on the typical diet.4 Food and salt, working together.
Fewer strokes with a potassium salt swap
In the SSaSS trial in rural China, almost 21,000 people with a past stroke, or aged 60+ with high blood pressure, cooked with a salt substitute that was 25% potassium chloride. After almost five years, they had fewer strokes (rate ratio 0.86), fewer major heart events and fewer deaths than villages using regular salt.5 Serious problems from high potassium were no more common in that trial. In 2025, the WHO suggested potassium-containing salt substitutes for adults in general, but explicitly not for people with kidney problems or anything else that affects how they get rid of potassium.6
The uncomfortable truth
"Sea salt and pink salt are healthier." They're still sodium chloride. Fancy crystals, nice jar, higher price. Your blood pressure can't read the label. The WHO limit counts all sodium, whatever it's called.1
"Low sodium fixes everything." Not for every condition. In the SODIUM-HF trial, 806 people with heart failure were put on under 1,500 mg of sodium a day. After a year, they had no fewer hospital visits or deaths than people on usual care.8 Salt still matters for blood pressure. But the exact limit for your heart or kidneys is something your specialist sets, because the evidence differs by condition.
The risks
- Salt substitutes and kidney disease. Potassium-based "lo-salt" products are not for people with kidney impairment or on drugs or supplements that raise potassium, such as potassium-sparing diuretics. The trials behind them excluded those people.6 Too much potassium in the blood (hyperkalaemia) can be harmful, especially when the kidneys don't work well. Ask your doctor before you buy one. See also our renal diet article.
- Blood pressure tablets. If you take blood pressure medication and your numbers drop a lot after cutting salt, your doses may need a review. Don't change them yourself.
- Hidden salt in medicine. Some dissolvable (fizzy) painkillers and vitamins contain a lot of salt.2 Ask your pharmacist for an alternative, and don't stop a prescribed drug on your own.
- Generic "salt your food" advice. Fasting and keto articles, including ours, often tell people to add salt to fight headaches and cramps. If you're on a prescribed sodium limit, that advice isn't for you. Ask your doctor.
- Food that tastes of nothing. Not dangerous, just miserable, and the main reason people give up. Lean on lemon, garlic, ginger, chilli, herbs and spices.
Allergies: watch the staples
Low sodium cooking leans on herbs, spices and "reduced salt" sauces. A few of those carry allergens people don't expect.
| Staple | Allergen (EU list of 14)9 | Swap |
|---|---|---|
| Reduced-salt soy sauce | Soybeans, often cereals containing gluten (wheat) | Lemon, vinegar, ginger, a little sesame oil |
| Celery salt, celery seed, spice blends | Celery | Pepper, garlic, herbs |
| Mustard powder, mustard | Mustard | Horseradish, chilli |
| Unsalted almonds, walnuts | Tree nuts | Unsalted pumpkin or sunflower seeds |
| Unsalted peanuts | Peanuts | Roasted chickpeas, no salt |
| Tahini, sesame dressing | Sesame | Olive oil and lemon |
| Plain yoghurt, milk | Milk | Unsweetened soy or oat yoghurt |
| Oats, wholegrain bread | Cereals containing gluten | Brown rice, potatoes, quinoa |
| Fresh fish | Fish | Chicken, eggs, legumes |
Don't set your own sodium limit if you…
- have kidney disease, heart failure or liver disease
- take blood pressure tablets, diuretics (water pills) or potassium supplements
- want to use a potassium salt substitute and have any of the above
- are pregnant or breastfeeding
- are under 18
Healthen me asks about all of these and gives you a different plan if any apply.
How we use low sodium in your plan
We don't plan prescribed low sodium diets. If your doctor gave you a number, your doctor or dietitian is the one to build meals around it.
Healthen me asks about kidney disease, heart problems and medication, and refers you to your doctor where that matters. People with kidney disease get a gentle, non-fasting plan and a clear "talk to your doctor first".
What everybody's plan does anyway: real food cooked from scratch, few packets, no instant noodles, no white bread, lots of vegetables, and flavour from herbs, spices, lemon and garlic. That's less salt by default. It's not a medical sodium limit, and we don't pretend it is.
This article is general information, not medical advice. If you have a medical condition or take medication, talk to your doctor before changing how you eat.
Sources
- World Health Organization. Sodium reduction (fact sheet). who.int/news-room/fact-sheets/detail/sodium-reduction
- NHS. Salt in your diet. nhs.uk/live-well/eat-well/food-types/salt-nutrition
- 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. doi.org/10.1136/bmj.f1325
- Sacks FM et al. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. New England Journal of Medicine 2001;344(1):3–10. doi.org/10.1056/NEJM200101043440101
- Neal B et al. Effect of salt substitution on cardiovascular events and death. New England Journal of Medicine 2021;385(12):1067–1077. doi.org/10.1056/NEJMoa2105675
- World Health Organization. Use of lower-sodium salt substitutes: WHO guideline. Geneva: WHO; 2025. who.int/publications/i/item/9789240105591
- Roerecke M et al. The effect of a reduction in alcohol consumption on blood pressure: a systematic review and meta-analysis. Lancet Public Health 2017;2(2):e108–e120. doi.org/10.1016/S2468-2667(17)30003-8
- Ezekowitz JA et al. Reduction of dietary sodium to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial. The Lancet 2022;399(10333):1391–1400. doi.org/10.1016/S0140-6736(22)00369-5
- Regulation (EU) No 1169/2011 on food information to consumers, Annex II (the 14 allergens). eur-lex.europa.eu/eli/reg/2011/1169/oj