Sodium citrate

Sodium citrate is a sodium salt derived from citric acid. In sports hydration it provides sodium and acts as a buffering agent, helping beverages maintain a slightly alkaline pH.

Role and physiological effects

Trisodium citrate, the most common form of sodium citrate, consists of three sodium ions bound to the conjugate base of citric acid. As a weak base it neutralises acids and is widely used in food and drink as an acidity regulator. When ingested it dissociates into sodium ions and citrate. Citrate is an intermediate in the citric acid cycle and can be metabolised by cells, while the sodium contributes to electrolyte balance. As a conjugate base, sodium citrate helps maintain blood pH and is used medically to treat metabolic acidosis. In sports hydration, sodium citrate is an alternative to sodium chloride because it delivers sodium without making a drink overly salty. Research on dehydrated athletes shows that supplementing with sodium citrate can increase water retention and expand plasma volume after weight loss. This expansion may aid rehydration and support cardiovascular function, but evidence that it improves performance is mixed. Unlike sodium chloride, which provides chloride ions, sodium citrate supplies citrate ions that are metabolised and can contribute to alkalosis.

Use in sports drinks and other examples

Food manufacturers use sodium citrate (E331) to control acidity in cheese, soft drinks and processed meats. It allows cheese sauces to melt smoothly and prevents milk proteins from curdling. In oral rehydration solutions and some sports drinks, sodium citrate replaces a portion of sodium chloride to reduce the beverage’s saltiness while still supplying sodium. Because the citrate is metabolised, drinks containing sodium citrate may have a milder taste and can be easier on the stomach than very salty formulas. However, large doses of sodium citrate supplements can cause gastrointestinal discomfort and diarrhoea, and the alkalinising effect may lead to metabolic alkalosis if consumed excessively. Most athletes can meet sodium needs with standard sports drinks and salty snacks, and supplementation with sodium citrate should be guided by a sports nutrition professional.

Sodium citrate is therefore a versatile salt that serves as both an acidity regulator and a source of sodium. In sports drinks it offers an alternative to table salt that can aid fluid retention and maintain pH, but its benefits over sodium chloride are modest. Athletes should consider the potential for gastrointestinal side effects and use it judiciously within a balanced hydration strategy.

Related Terms: sodium bicarbonate, potassium citrate, magnesium citrate, hydration, prehydration