A recent study examining the hydrating properties of a variety of fluids found that after electrolyte drinks (oral rehydration solutions), milk was the next best thing in terms of hydrating properties.
How fluid is best ingested
While both the volume and composition of the fluid ingested influence how quickly fluid leaves the stomach (and gets absorbed in the small intestine), the composition of the beverage can also affect how quickly the fluid leaves the body. The protein, carbohydrate and energy content of milk, slows down the rate at which it leaves the stomach (called gastric emptying), and promotes better fluid retention (i.e. more time for the fluid to be absorbed).
Plenty of variety, but which one is best?
However, gone are the days where most of us just drink plain cow’s milk. A trip to the supermarket 20 years ago allowed a limited choice of dark blue, light blue or green top milk with one variety of soy milk. Enter the modern supermarket today and you are spoilt for choice. Almond milk, coconut milk, soy milk (fortified or milky), and a wide variety of normal cow’s milk (calcium fortified or yellow, higher protein milk). But how do they stack up nutritionally?
* Added Cane Sugar
** Unsweetened Coconut Milk
The importance of protein and calcium
For an athlete, or any person, both protein and calcium are important for muscle and bone health. If you are using an alternative milk check to see if it is providing enough protein and calcium. Watch out for added sugars too. Many alternative milk products use added sugars to sweeten the product and make it more palatable (taste better).
Milk’s perfect combination
In summary, all fluids count towards overall hydration status (except of course large quantities of alcohol). Drink often, carry a drink bottle with you, and think about milk as a good option post-training. It provides all the elements: protein, calcium, fluid, and sodium – a perfect combination.