A Guide to Electrolytes

Electrolytes are essential minerals that are used in various metabolic processes within the body.

Common electrolytes include:

• Sodium

• Potassium

• Calcium

• Magnesium

• Chloride

The main role of electrolytes is to balance water and pH levels, and to transport nutrients into the cells. Electrolytes also support muscle and nerve function, with a major role in assisting the contraction of muscles during exercise. While electrolytes are essential minerals that are required to be consumed through the diet, most people, including athletes, do not require electrolyte supplementation. Fruits and vegetables are high in electrolytes and generally provide the body with all its electrolyte needs. Diets consisting of processed foods are often high in one particular electrolyte, sodium. Consuming supplemental electrolytes can cause excess consumption of sodium if the diet is already high in ultra-processed foods.

Sports/ Electrolyte Drinks

Glucose (sugar/ carbohydrate) is required in electrolyte drinks for the absorption of electrolytes and water. Without sugar, these beverages are ineffective.

Typical sports drinks contain about 0.5g/L sodium (~300mg per 600mL bottle) and 6% carbohydrates (glucose, sucrose). Electrolyte beverages replace any losses during exercise and promote carbohydrate replenishment for energy use. Sports drinks containing sodium also help create osmotic differential for enhanced water and glucose absorption into the cells. Sports drinks are generally only required with 60+ minutes of high intensity, endurance exercise (running, swimming, riding, team sports).

Glucose is absorbed in the body with the assistance of sodium using sodium-dependent glucose transport proteins (SGLT). The individual monosaccharides (glucose) and sodium attach to the SGLT to be co-transported across the membrane using the electrochemical gradient for energy. This mechanism depicts the importance of sodium for glucose absorption when the concentration gradient is not in favour. 

Did you know you need sugar to absorb electrolytes?

• Yes
• No

Sodium

Regulated by the hormone aldosterone, sodium is the major cation in extracellular fluid. Sodium contributes to nutrient absorption, muscle contraction, and electrical potential charge. It is important to keep sodium levels regulated in the body to ensure extracellular volume is constant to maintain healthy blood pressure and cardiac output levels. To maintain sodium levels, water is either lost or retained to balance concentrations. The average adult only requires 460-920mg per day of sodium, however most Western diets consist of much more, increasing the risk of various chronic diseases.

Chloride

Anion in extracellular fluid that is mostly obtained through salt consumption. Chloride helps to balance water, body fluids and blood pressure by working with other electrolytes (potassium and sodium).

Potassium

Potassium is a major cation in intracellular fluid that controls blood volume and fluid levels. Potassium also plays a role in nerve impulse transmission, muscle contraction, lowering blood pressure, enzyme anabolism and electron transport. Potassium is found in fruit, vegetable, milk, grain, meat and bean food sources. The daily intake of potassium is 2000-3000mg. Deficiency of potassium can cause muscle cramps, confusion, irregular heartbeat. 

Harada N, Inagaki N. Role of sodium-glucose transporters in glucose uptake of the intestine and kidney. Journal of Diabetes Investigation. 2012:3(4);352–353. Available from: https://doi.org/10.1111/j.2040-1124.2012.00227.x