Does any drink serve us to hydrate properly, both when doing sports and in our daily lives? The answer is no, and to measure it we have the hydration index of beverages : a factor that tells us the amount of time that a fluid stays in our body before excreting it through urine.
This index was recorded from another well-known: the glycemic index or glycemic index of foods, which measures the response of the organism to the intake of carbohydrates of a given food. The hydration index guides us when choosing the type of drinks with which we are going to hydrate to find out which one is most convenient for us at all times. Knowing this, what drink do you think has a better hydration index: milk, orange juice or a sugary soft drink?
A British study published last year clarified us this question: of the 13 drinks tested on 72 subjects, using water as “control drink”, the best rate of hydration obtained were, in this order, the oral solution based mineral salt, skim milk and whole milk. Immediately behind them without the podium orange juice, cola and iced tea are left.
According to this study, these three drinks were able to retain a greater amount of fluids in the body up to two hours after ingesting them. Of course, this was done in a controlled environment and on subjects in a state of euhydration (with a normal body water content, not dehydrated or excessively hydrated).
That an oral solution with mineral salts comes out winning in this comparison can not surprise us much: at the end of the day it is a drink formulated expressly to rehydrate our body. But what really catches our attention is the fact that milk, whether skimmed or whole, has such a good hydration rate . This, according to Ronald J. Maughan, hydration expert at the University of Loughborough, is because being a drink that contains other nutrients and electrolytes, its consumption slows down gastric emptying, and this directly affects the kidneys, which produce less urine.
It is also striking that sports drinks obtained a very low hydration index in this study, given that in their advertising they always sell them as one of the best ways to rehydrate after sports. Beer was also one of the worst stops in the comparison: beer is not a good option when rehydrating.
It is a good idea to remember that the reference drink, both in this study and in our day to day and when we practice sports activities, should always be water(and it is the one taken in this study as a reference).