Your eight glasses a day may not be all that healthy
We all do it, in fact to survive, we have to do it! But what is it that drives us to drink? It seems like a no-brainer – thirst! But that doesn’t explain why we’ve increased our consumption of fluids by about 1% per year over the last 30 years. And why only some of that increase has even been from water.
According to research conducted by Dr. Heinz Valtin from Dartmouth University, there has been an increase of fluid consumption in the vicinity of 30% over the past 30 years. Whilst the good news is that water has increased 24%, alcohol (up 100%), soft drinks (107%), and fruit juices have increased a whopping 143% in just 30 years. Although this is specific to the US, there are parallels to be drawn here in Australia.
While social drinking has probably increased, this doesn’t explain why people seem to be more attached to water bottles these days than babies are to mother’s teats. This is particularly interesting when most of these cost a premium, while great quality water is available free from the taps.
Could it go back to the popular notion that we need ‘eight glasses of water/fluid a day’? If so, where does this recommendation come from? And on what is it based? Also, are there any other factors that influence our fluid intake?
The 8 glasses a day suggestion – quoted by just about all doctors as coming from their patients – was the basis of an intensive search by Dr. Valtin in 2002. He found no basis for its suggestion. In fact, he says, humans need between 1.5-4L (or 6-16 glasses) a day of fluid, depending on a number of different conditions (age, heat, gender, body size etc.)
Still, it’s a belief that has stuck, with Valtin showing that the increase in over-all fluid consumption has come since the belief (in the 1970s) about 8 glasses a day became widespread.
Sweetened drinks
Apart from water, sweetened drinks have increased. There are two types: nutritive (ie. naturally sweetened with calorific mixes like sucrose) and non-nutritive or non-calorically sweetened (ie. with
artificial sweeteners like aspartame). Desire for a sweet taste is obvious, but why the need for so much?
Research on learning shows that people who drink sweetened drinks when thirsty, tend to crave those drinks. This is the Pavlovian conditioning phenomenon. However, if a nutritive sweet drink (eg. like Coke) is drunk even when hungry, there is an increased desire for this the next time hunger strikes!
This can be a problem, because these have calories and therefore can be more fattening.
The tactic, it would seem, is to only drink water when genuinely thirsty. For a treat, non-nutritive soft drink is OK, but full-strength soft drink should be avoided or only drunk sparingly.
Juices and other drinks
Despite popular opinion, fruit juices – which have also accounted for the huge intake in fluids – are not exceptionally healthy. They are concentrated in sugars and are therefore quite fattening. Tea, low fat milk and soy drinks on the other hand, are all low in energy and have other benefits. Tea has a high level of anti-oxidants, which fight the effects of other misdemeanours.
Dairy and soy products are high in proteins and calcium and other essential nutrients. Their intake can be increased. Coffee can also be increased – to a point (ie. 4-6 cups/day), in those who are not so caffeine sensitive. Also while non-nutritive sweeteners may be OK for the weight conscious, their acid content (like fruit juice) is not recommended for teeth. They should be drunk through a straw and preferably followed by no-sugar chewing gum.
Fashionable bottled water drinkers who sip this throughout the day might also not be doing their teeth a favour, as this can dilute saliva in the mouth, reducing its ability to fight bacteria.
So at the end of the day your belief that for good health you need to hydrate regularly may be not so important especially if you are hydrating from sources other than water. The bottom line is simple – H2O is the go (with a few others in between).
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