Science Of Drinking Water – Hydration and Health

Most of us know the importance of water on the body. It is an essential item for life. And we have been thought in school that the body is made up of approximately 70% of water and we need to drink 8 cups of water daily. Some might also have read about the various timing of drinking water and its benefit. I begin to wonder how much of what we read are true. And so I embark on the journey to find out more on the …


Science of Drinking Water


Role of Water On Human

Water play an absolute critical role in the body. Without water, human will day in a few days. First and foremost, water helps to regulate the temperature in the body. Next, water prevents dehydration, balances the ions to maintain healthy cells, influence cognition, maintain the various organ systems function. Many might not have noticed that lack of water might lead to headache too.



One of the common myth about water is that it improves skin complexion when you have about 8 cups per day as it “flushes toxin” out of the body. There is a lack of evidence pointed out by Valtin H in the review.


How much of Water do we need?

We have been hearing about the need for 8 cups of water daily. Is this a truth or a myth? And how much of water do we really need each day?

Based on the National Academy Press report by the Institute of Medicine of the National Academy of Science on Dietary Reference Intakes on Water and Electrolytes as reported in 2005, it stated that “While it might appear useful to estimate an average requirement (an EAR) for water, an EAR based on data is not possible”. In other words, there is no possible recommendation on the amount of water required.

It was also acknowledge by Vivanti AP (2012) the importance of estimating the amount of water required for human as a guides.


Is there any side effect of large amount water?

I could not find any published publication on the negative effect of large amount of water on the body. Per Valtin H review, it was stated that there were few negative effects.


Some Additional Benefits of Water

Anjali S. Joshi and et al conducted a study on the effect of execessive water intake on body weight, body mass index, body fat, and appetite of overweight female participants. The result is indicative that the effect of water is positive on weight loss, but more study on this area is required.



Despite there isn’t any possible recommendation in the amount of water required, neither is there much side effect on drinking large amount of water plus there is an indication that excessive water may help in weight loss, there is any harm in having 8 cups or more.

On the other hand, we are certain that should human have little or no enough of water, it will bring about a whole consequence of effect from gastrointestinal to headache.





Valtin H“Drink at least eight glasses of water a day.” Really? Is there scientific evidence for “8 x 8”? Am J Physiol Regul Integr Comp Physiol. 2002 Nov;283(5):R993-1004.

Meinders AJ1, Meinders AE. [How much water do we really need to drink?]. Ned Tijdschr Geneeskd. 2010;154:A1757.

Sawka MN1, Cheuvront SN, Carter R 3rd. Human water needs. Nutr Rev. 2005 Jun;63(6 Pt 2):S30-9.

Popkin BM1, D’Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58

Negoianu D, Goldfarb S. Just add water. J Am Soc Nephrol. 2008;19:1041–1043.

Jequier E, Constant F. Water as an essential nutrient: the physiological basis of hydration. Eur J Clin Nutr. 2010;64:115–123.

Panel on Dietary Reference Intakes for Electrolytes and Water.Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington DC: National Academy Press; 2005. [Ref list]

Vinu Ashok Kumar Vij and Anjali S. JoshiEffect of excessive water intake on body weight, body mass index, body fat, and appetite of overweight female participants. J Nat Sci Biol Med. 2014 Jul-Dec; 5(2): 340–344.

Vivanti AP1. Origins for the estimations of water requirements in adults. Eur J Clin Nutr. 2012 Dec;66(12):1282-9