Sodium

Sodium is essential to life: too little (rare in healthy adults but a medical emergency in severe dehydration or salt-losing illness) is as harmful as too much. The UK story is one of consistent over-intake, with population blood pressure and cardiovascular consequences. Reducing salt across the UK food supply is one of the most studied public-health nutrition interventions of the last two decades.

This entry is intentionally brief because the longer-form treatment, including practical shopping advice, the front-of-pack traffic-light system, and the food-industry reformulation story, lives in the Salt and sodium article.

The UK dietary salt supply has three main routes onto a plate: processed and packaged foods (the biggest contributor, including bread, breakfast cereals, sauces, ready meals, processed meats, and cheese), eating out and takeaway food, and salt added at home. Most UK adults get the majority of their sodium from the first two routes.

For specific food values, food labelling guidance, and front-of-pack interpretation, see Salt and sodium.

The UK gives salt targets rather than separate sodium values for everyday use. The conversion: 1g of sodium = 2.5g of salt.

SACN 1991 also set Reference Nutrient Intakes for sodium (the minimum needed for normal physiology, far below the targets above): around 1.6g per day for adults. The day-to-day UK conversation is dominated by the maximum salt targets, not the minimum sodium RNI, because over-intake is the problem.

Sodium deficiency from diet is unknown in healthy adults eating any normal diet. Low blood sodium (hyponatraemia) has medical causes: severe dehydration, salt-losing illness, some medicines, and excessive plain-water intake during endurance exercise.

For practical UK nutrition, the relevant story is over-intake, not deficiency.

The UK targets above are themselves the upper-limit framing: no more than 6g of salt (2.4g of sodium) a day for adults.

Sodium supplements are not normally recommended for healthy adults. Salt tablets are sometimes used in specific endurance-sport or industrial-heat contexts, on specialist advice.

Routine sodium supplementation is not recommended for the general UK population. The day-to-day issue is reducing intake, not adding to it.

• Editorial home: Salt and sodium covers the UK 6g target, food labelling, blood pressure evidence, and practical shopping advice.
• The potassium counterpart: Potassium (the inside-cell ion that pairs with sodium for fluid balance and blood pressure).
• Chloride: Chloride (the other half of dietary salt).

• NHS. Salt: the facts. nhs.uk/live-well/eat-well/food-types/salt-nutrition.
• SACN. Salt and Health. 2003 review (the source of the UK 6g adult target).
• SACN. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Department of Health Report 41 (1991).

This page is reference information for UK shoppers. It is not medical advice.