Lab Cat

5 Jun 2006

Water – How much is enough?

Filed under: Food, Science, water — Cat @ 10:43 pm

half full

 

Last time I discussed whether or not water should count as a nutrient. While it does not supply nutrients, water is essential for life. We die a lot quicker from dehydration than from starvation. So why do we need water?

Water is a vital part of many metabolic processes within the body, and significant quantities of water are used during the digestion of food (link).

We all know, at least I hope we do, that we are mostly water. Check Attila the Stockbrocker’s poem if you not sure about that! Water is good for us as it is required for major bodily functions such as circulating solutes, oxygen and wastes. It also helps with temperature regulation, hence we sweat when we are too hot as the evaporation process helps us cool down. It also acts a cushion for our organs and tissues.

So how can be sure we are getting enough. According to the BBC there are three sources of water available to us:

  • From drinks, either plain water or as part of other beverages.
  • From solid foods, especially fruits and vegetables.
  • As a by-product of chemical reactions within the body.

We typically are told that we need 64 fl oz of water per day. There is no evidence for this amount and if we just consumed it as water it might be too much to handle. However, unlike the other articles quoting Dr Valtin, I suggest we do want to be careful that we drink enough. When I forget to drink enough I get headaches and feel generally lethargic. This typically goes away once I have ingested enough water. I do think the idea that you are dehydrated before you are thirsty is rather silly though. It is also true that many people don’t recognize their thirsty signals and hunger can get confused with thirst. However, not drinking because you are embarrassed about urination is also rather stupid*. Give those kidneys a break! In 2004, the National Academy of Sciences reported that women were properly hydrated when they consumed 91 oz (2.7 litres) and men at 125 oz (3.7 l) per day of total water – that is from all beverages and foods.

Also bottled water isn’t necessarily any better than tap (faucet) water. In fact the regulations covering tap water are more stringent than for bottled water. Most Brits also haven’t recovered from the Dasani fiasco when it turned out that Coca Cola were taking Thames tap water and making it undrinkable and charging for the privilege. Admittedly the tap water here tastes so bad that I have a PUR filter on the tap in the kitchen. This must mean that it tastes worse than London water, which I drank as undergrad despite being told on the first day of college that it had been through seven people before it reached London.

There is also hard and soft water. The difference between them is that hard water contains more dissolved minerals. This seemed more important in Britian when you could move to the next town and be moving from a hard to a soft water area. Birmingham, UK, where I grew up, takes its water from the Valleys of Wales** and the water is very soft. A tiny bit of soap gives a terrifc lather and scum never forms on tea or blocks pipes or kettles. Leeds water contains lots of calcium salts, I assume it is because it is filtered through the limestone pavements of Malham or similar beauty spots. We had to regularly clean kettles using citric acid and I would take distilled water home to use in my iron. Having written that, I realise that I should point that drinking hard water is meant to be healthier for you than drinking soft water. Those extra minerals help reduce heart disease or something.

Does water taste? I refer to my comment above about Newark and London water. Moving from one town to another shows how much water does taste and change in taste depending on its source. Water isn’t totally tasteless and it also absorbs flavors very easily. The plastic used to bottle water has to be a higher grade than used for other beverages as any flavor leaking into the water will be noticed. The difference in water taste can also be a problem for bottling companies and for drink fountains. If the water isn’t treated properly, the consumer will notice the difference.

Do I drink enough water? Possibly not, in the summer here in Delaware it gets so hot and humid that I feel that I can’t drink enough water to keep hydrated. At this stage, I have drunk so much water that I can’t take in another drop; even sports drinks don’t help. Eventually I stop cycling to work as the journey home on 90+ F heat and similar humidity is just too uncomfortable. In winter in Minnesota, I also dried out very quickly. This time for the opposite reason, there being no moisture in the air, my own water was evaporating and not being replaced. Skin, even on my legs, which never saw daylight in winter, would dry out and start chapping.

*I read this some where on the web and now I can’t find it. Probably fortunately, as suggesting you should stopping drinking as it makes you pee too much is not a reference worth visiting.

**B’ham water comes from Elan Valley, and I now live in Elan subdivision. How’s that for a coincidence [cue theme music from Twilight Zone]?

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3 Comments »

  1. Bottled water is a scam. You are buying the bottle not the water. I’ve noticed how many fewer drinking fountains are around now that water is sold in vending machines.

    I don’t trust water I can’t taste or air I can’t see (j/k). I used to live in Tampa, Florida where the water has a terrible sulpher taste. Yuck.

    Comment by yellojkt — 8 Jun 2006 @ 10:16 am

  2. […] Much Water I mentioned in a previous post how much water we should drink but I don’t think I emphasized enough that you can have too […]

    Pingback by Too Much Water « Lab Cat — 18 Jan 2007 @ 6:23 pm

  3. My son after football trainings spends all the pocket money on so-called ” drinks for sportsmen “. Whether they are of use? Or there is more than harm? WBR LeoP

    Comment by World Health — 29 Jan 2007 @ 10:47 am


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