Heart failure diet: sodium, fluid and beyond

By the DieticiansWorldwide.com editorial team · 18 October 2026 · Clinical nutrition

Why diet still matters in heart failure

Heart failure means the heart cannot pump well enough to meet the body's needs, and the body responds by holding on to salt and water. For decades the response was a strict low-salt, low-fluid diet sheet handed out at discharge. That advice was logical, but much of it was never tested in people taking modern heart failure medicines.

The picture has changed. The Heart Failure Association (HFA) of the European Society of Cardiology (ESC) said in its 2024 consensus statement that "recent data challenge the beneficial role of dietary sodium and fluid restriction" in heart failure, and that ESC guidelines "have gradually downgraded these recommendations over time" (Mullens and colleagues, European Journal of Heart Failure, 2024).

That does not mean diet no longer matters. It means the focus has widened: avoiding the very salty foods that trigger fluid build-up, eating enough protein and energy to protect muscle, spotting malnutrition and cachexia early, managing iron deficiency, and watching your weight for early signs of congestion. This guide covers each in turn. It is general information; your heart failure team will set your own sodium and fluid targets.

What the guidelines say about sodium

Europe

The HFA consensus describes current ESC advice as "limitation of salt intake to no more than 5 g/day in patients with HF, while contemplating fluid restriction of 1.5-2 L/day only in selected patients". Salt is about 40% sodium, so 5 g of salt contains roughly 2 g of sodium. The ESC published a new heart failure guideline on 28 August 2026, which reclassifies heart failure and updates treatment indications (ESC Clinical Practice Guidelines). Ask your cardiology team which version your local protocol follows.

United Kingdom

NICE's guideline on chronic heart failure in adults, NG106, first published in September 2018 and last updated in September 2025, is notably cautious. It says: "Do not routinely advise people with heart failure to restrict their sodium or fluid consumption." Instead, clinicians should ask about salt and fluid intake and, if needed, advise restricting fluids for people with dilutional hyponatraemia (low blood sodium caused by excess water) and reducing intake for people with high salt or fluid consumption, then keep reviewing the need (NICE NG106).

United States

A 2025 review of salt restriction across heart failure types summarises the 2022 AHA/ACC/HFSA guideline as suggesting that people with stage C heart failure avoid excessive sodium intake to reduce congestion, "while acknowledging the absence of robust trial evidence in this population". The same review notes that the Canadian Cardiovascular Society suggests 2 to 3 g of sodium a day (Journal of Cardiovascular Development and Disease, 2025).

What recent trials changed

SODIUM-HF: a lower sodium target did not cut events

SODIUM-HF enrolled 806 adults with chronic heart failure in six countries, all on optimised medicines. Half were advised to eat less than 100 mmol of sodium a day (under 1,500 mg) and half received usual care. Sodium intake fell from a median of 2,286 mg to 1,658 mg a day in the low-sodium group. After 12 months, the combined outcome of cardiovascular hospital admission, cardiovascular emergency visit or death from any cause occurred in 15% of the low-sodium group and 17% of the usual-care group, a difference that was not statistically significant. The authors concluded that "a dietary intervention to reduce sodium intake did not reduce clinical events" (Ezekowitz and colleagues, Lancet, 2022).

Two points matter when you read that result. The usual-care group was already eating only about 2,100 mg of sodium a day, so the trial compared moderate with lower intake, not high with low. And the trial was open-label and smaller than many drug trials. The evidence suggests that pushing below moderate intake adds little for most outpatients; it does not show that very salty eating is harmless.

FRESH-UP: liberal fluid advice was safe in stable patients

FRESH-UP randomised 504 outpatients with chronic heart failure to advice for liberal fluid intake or to a restriction of up to 1,500 ml a day. After 3 months, health status scores were similar (74.0 versus 72.2 on a standard questionnaire, not statistically different), thirst distress was higher in the restricted group, and there were no differences in safety events. The investigators wrote that their findings "question the benefit of fluid restriction in chronic heart failure" (Herrmann and colleagues, Nature Medicine, 2025).

The strength of evidence is moderate: these are single randomised trials in stable outpatients, not in people admitted with severe congestion or low blood sodium. Fluid limits still have a place for selected patients, and that decision belongs to your team.

Should heart failure patients restrict fluids?

Not routinely, but some people still need to. Situations where your team may set a limit include:

• low blood sodium caused by excess water (dilutional hyponatraemia), which NICE singles out;
• severe or advanced heart failure with persistent congestion despite diuretics;
• people who habitually drink very large volumes;
• coexisting kidney failure on dialysis, where fluid rules are set by the kidney team. Our guide to the work of a renal and kidney disease dietitian explains how those allowances are worked out.

If you have been given a limit, ask what it is based on, when it will be reviewed, and whether foods that are liquid at room temperature count. If you have not been given one, do not invent your own. The 2025 review cited above notes that studies combining sodium and fluid restriction with high-dose diuretics reported rises in creatinine and urea, a sign of strain on the kidneys.

How much sodium is allowed in heart failure?

For most people, the practical target is to avoid excessive salt rather than chase a very low number. European guidance caps salt at about 5 g a day in total from all foods, which equals about 2 g of sodium. Canadian guidance suggests 2 to 3 g of sodium.

Most salt comes from processed and restaurant food, not the salt shaker. Our low-sodium diet guide shows how to read labels and swap the biggest sources. Good starting points:

• choose fresh or frozen meat and fish over cured, smoked or processed meat;
• cook from scratch more often, using herbs, spices, garlic, lemon and vinegar for flavour;
• check bread, breakfast cereals, cheese, sauces, stock cubes and soups, which add up quickly;
• limit takeaways and ready meals to occasional use;
• rinse tinned vegetables and pulses.

NICE adds a specific safety warning: "Advise people with heart failure to avoid salt substitutes that contain potassium." Many heart failure medicines raise blood potassium, and potassium-based salt replacers can push it to dangerous levels.

What foods should be avoided with heart failure?

Very few foods are banned outright. The main groups to limit are:

1. Very salty processed foods: bacon, ham, sausages, salami, crisps and salted nuts, instant noodles, stock cubes, soy sauce and many ready-made meals.
2. Potassium-based salt substitutes, unless your team has approved them.
3. Large amounts of fluid at once, if you have been given a fluid limit.
4. Alcohol beyond what your doctor advises. NICE's heart failure guideline points clinicians to its separate alcohol guidance, so ask for your personal limit.
5. Unprescribed supplements and herbal remedies, which can interact with heart medicines or contain hidden sodium or potassium. Check with your pharmacist.

Eating patterns built around vegetables, fruit, pulses, wholegrains, fish and unsaturated oils, such as the Mediterranean diet, suit most people with heart failure. The DASH diet is also lower in salt, but it is high in potassium, so check with your team if your potassium runs high on medicines.

Protein, weight loss and cardiac cachexia

The biggest nutrition risk in heart failure is often not too much salt but too little food. Breathlessness, early fullness from a congested gut, nausea, low mood and strict diet sheets can all reduce intake.

Cardiac cachexia, which combines weight loss with weakness, fatigue, poor appetite and abnormal blood markers, is common and serious. A 2024 meta-analysis found a pooled prevalence of 31% across 10 studies of 2,862 patients, and in six studies people with cachexia had a significantly higher risk of death from any cause (hazard ratio 1.60) (Prokopidis and colleagues, Journal of Cachexia, Sarcopenia and Muscle, 2024). The 2025 review cited above warns that in older people with heart failure, sodium restriction has been linked to reduced appetite, lower energy intake and malnutrition.

NICE asks clinicians to include nutritional status in routine heart failure reviews, alongside fluid status and kidney function. In practice:

• Weigh yourself regularly and tell your team about unplanned weight loss as well as sudden gains, because fluid can hide muscle loss.
• Spread protein across the day, with a protein food at each meal: eggs, fish, chicken, yoghurt, milk, tofu, beans or lentils. Our protein calculator gives a starting estimate, but your dietitian may set a higher target if you are losing muscle.
• Eat little and often if breathlessness or fullness limits portions.
• Ask about oral nutritional supplements if intake stays low, and check their sodium content with your dietitian.

Loss of muscle with age, or sarcopenia, makes heart failure symptoms worse and recovery slower, so protein and activity matter as much as salt. If you are on diuretics and eat little, your team may also check for deficiencies; our guide to B12 deficiency explains which symptoms to mention.

Iron: a deficiency food alone may not fix

NICE updated its heart failure guideline in 2025 to address iron deficiency. It now recommends that people with heart failure with reduced ejection fraction have their iron status checked with transferrin saturation, ferritin and haemoglobin, and that intravenous iron be considered when iron is low (transferrin saturation under 20% or ferritin under 100 nanograms per ml) and haemoglobin is under 150 g per litre.

Iron-rich foods are part of a healthy diet, but they are not a substitute for this testing and treatment. Our guide to iron supplements explains why oral tablets are not always the answer.

Weight, overweight and heart failure

Some people with heart failure are also living with obesity. Gradual, supervised weight loss may help some of them, but rapid or very low-calorie dieting can cause muscle loss and needs medical supervision if you take diuretics. Safe approaches are set out in our article on choosing a dietitian for weight loss, and the fatty liver diet guide is relevant because liver fat often travels with the same metabolic risk factors.

Generic diet sheet or an individual plan?

A generic cardiac diet sheet usually gives one sodium number, one fluid limit and a list of foods to avoid. It cannot tell whether you are eating too little, whether your potassium is high from medicines, whether you have kidney disease, or whether a fluid limit is still needed months after discharge. NICE's advice to keep reviewing salt and fluid restrictions reflects exactly this problem.

An individual plan from a dietitian starts with what you actually eat, your medicines, blood results, weight trend, appetite, culture and budget, then sets priorities. For one person that will be cutting takeaway meals; for another it will be adding protein and lifting an old fluid limit with the team's agreement. People with a long history of restricted eating, such as ARFID, need particular care, because a new list of "bad" foods can make intake worse. To confirm a UK dietitian's registration, see the United Kingdom country guide.

In the US, Medicare Part B currently covers medical nutrition therapy only for diabetes, kidney disease and recent kidney transplant. A Senate bill introduced in February 2026, S. 3934, would extend coverage to conditions including cardiovascular disease, malnutrition and cancer (GovInfo). Until then, check whether your insurer or heart failure clinic offers dietitian sessions.

Book a session with a dietitian

How strict does the heart failure diet need to be?

Strict enough to avoid fluid overload, and no stricter. A reasonable reading of the current evidence:

• Stable outpatients on optimised medicines: avoid very salty processed foods and keep salt moderate. Most do not need a fixed fluid limit.
• Recent admission with congestion: your team may set temporary sodium and fluid limits; ask when they will be reviewed.
• Low blood sodium or advanced heart failure: fluid restriction is more likely to be needed and should be supervised.
• Weight loss, poor appetite or frailty: eating enough comes first; relax restrictions with your team's agreement.

Our healthy eating check gives a quick snapshot of your overall pattern; treat it as a conversation starter for your team, not a replacement for their advice.

Warning signs that need urgent help

The NHS advises asking for an urgent GP appointment or calling NHS 111 if you have heart failure symptoms and feel breathless when lying down or from everyday activity, are coughing up frothy pink phlegm, or have suddenly gained weight. Call 999 or your local emergency number if you have severe difficulty breathing, if your lips or skin turn pale, blue or grey, or if someone collapses and is not responding normally (NHS, heart failure).

The NHS also lists swelling in your feet, ankles, legs or tummy, feeling light-headed or dizzy, and coughing at night among heart failure symptoms, so tell your team promptly if any of these are new or getting worse.

The practical takeaway

• Avoid very salty processed foods; most guidance points to moderate salt, around 5 g a day or less, rather than very low targets.
• Fluid restriction is no longer routine for stable patients; it is for selected people and is set by your team.
• Avoid potassium-based salt substitutes.
• Protect protein and energy intake; cachexia affects around a third of patients in pooled studies.
• Ask about iron testing, weigh yourself regularly and know the warning signs.