Water is not the best option for hydration - Study

The study compared the hydration response of various drinks and came to the conclusion that beverages with a bit of sugar, protein or fat, excel at keeping the body hydrated for longer periods.

According to Prof. Ronald Maughan, of St. Andrew's School of Medicine, the reason is in the body's response to each beverage.

Volume of a drink

The more beverage you drink, the faster it is emptied from the stomach and absorbed into the bloodstream.

Drink's nutrient composition

Milk was found to be more effective in hydrating than water because it contains fat, protein and sugar lactose, all of which slow down the emptying of the fluid from the stomach thus prolonging hydration.

Moreover, milk has sodium which acts as a sponge that retains water slowing down urine production.

In the same way, Oral Rehydration Solutions used in diarrhea treatment, support water retention by way of the sodium and potassium contained in them.

Thus, the research team at St. Andrew University compiled a list of 13 common beverages to find out which one has the greatest impact to the least for hydration over a 4-hours period.

Skim milk, oral rehydration solutions (like Pedialyte or Liquid I.V.), full fat milk, orange juice, cola, diet Cola, cold tea, tea, sports drink, still water, sparkling water, lager, and coffee.

"This study tells us much of what we already knew: Electrolytes -- like sodium and potassium -- contribute to better hydration, while calories in beverages result in slower gastric emptying and therefore slower release of urination," said Melissa Majumdar, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics.

Sugar in moderation

But before you skip to the refrigerator to celebrate with a glass of processed juice or Coca-Cola, these beverages with high sugar concentration, although they take longer in the stomach, once they enter the small intestines, they pull the water they just gave the body from the bloodstream back into the small intestines by a physiological process called osmosis.

Eliminating dehydration

However, you should not worry too much about how hydrating a particular beverage is, if you are thirsty the body will direct you to drink more.

"Beer would result in less water loss than whiskey, because you are ingesting more fluid with beer. Strong alcoholic drinks will dehydrate, dilute alcoholic drinks will not," Maughan says.

For people who don't typically drink caffeine, it can have a short-term diuretic effect making them urinate more often than the regular users. However, this can be balanced out by adding a bit of sugar or milk to the coffee.

According to research, regular coffee of about 80 milligrams of caffeine is as hydrating as water for accustomed users.