Hydration qualities of milk

The New York Times published an article recently on the findings of a new “beverage hydration index”, which analysed the hydration effect of 13 different beverage types.

72 British men in their mid-20s each consumed 1 litre of water and the index was set at 1.0 for the amount they had not passed in urine 2 hours later.

4 beverages were found to have a “significantly higher hydration index than water.” An oral rehydration solution, fat-free milk and whole milk all scored around 1.5. Orange juice scored 1.1.

Lead author Ronald Maughan from Loughborough University commented: “When beverages contain nutrients and electrolytes like sodium and potassium, as milk does, the stomach empties more slowly with a less dramatic effect on the kidneys.”

Drinks containing caffeine, alcohol and higher sugar levels “had hydration indexes no different from water.” As Ronald Maughan elaborated: “It’s true that caffeine is a diuretic, but not at the concentration found in most coffee drinks.”