Water is often overlooked when it comes to nutrition, either because people assume keeping hydrated is a given, or because water doesn’t contain any nutrients per se. Yet water is one of the most important part of your diet, and this article will investigate how much water we should drink, highlight the problems dehydration can cause, and how to keep hydrated.
How much water should I drink?
There are a number of recommendations for how much water you should drink, but the most common recommendation is that you need to drink 8 pints/ glasses of water a day. Although this will do you no harm, there is actually no evidence for this being the correct amount to drink, and even the origins for this claim are vague and difficult to pin point. The NHS and European Food Safety Authority recommends 1.6 litres of water for women, and 2 litres of water for men, but even this is based on very little research, and is more of an estimate, and both organisations admit that it is impossible to give an accurate guideline for many reasons.
In reality, requirements can vary dramatically from person to person depending on size, height, weight, activity level, temperature of environment and especially diet, so a ‘one size fits all’ rule cannot apply here. The water content of food varies dramatically, which will affect the amount you need to drink. For example, nearly 70% of cooked rice (by weight) is water, and most fruits and vegetables are around 90% water by weight, whereas nuts/ seeds and grains are rarely more than 5% water by weight. This dramatic variation, combined with varying exercise levels can mean that you could need to drink anywhere between 1 and 4 litres a day.
The most accurate way to gauge how much you should be drinking is by observing biological markers of dehydration. These include:
- Urine colour (which will be yellow, or even dark yellow if you are dehydrated. It should be pale yellow or even clear).
- Feeling tired/ lethargic/ low energy
- dry eyes
- dry throat/ thirsty
These are signs of mild dehydration, which means you need to consume fluids soon. Ideally, you want to avoid experiencing mild dehydration all together, and the best way to do this is regularly drink water, and to make sure you drink plenty of rehydrating fluids before, during and after exercising.
Water itself doesn’t undergo any biological reactions in the body, but rather it is the medium in which reactions take place, and so is vital for all biological reactions. The body is very quick to recover from mild dehydration if it is not experienced often, but regular dehydration (or chronic/ prolonged dehydration) can cause health problems.
The most common health issue associated with dehydration is the development of kidney stones. These form is small tubes inside the kidney, which are responsible for water regulation in the body and producing urine. If you are dehydrated, waste products, which should be passed out in the urine, form crystals because there is not enough water to dissolve them, and these crystals can become ‘lodged’ in the tube and cause sever pain and discomfort. Recurring/ chronic dehydration can also cause very stiff joints, which makes them much more vulnerable to damage, especially if you partake in exercise or any activity which puts strain on joints. If you are dehydrated you may also experience constipation or other digestive issues which originate from not having enough fluid for the intestines to move the chyme (ball of semi-digested food) through the digestive system.
These symptoms are noticeable, because they cause discomfort, but dehydration can also cause an imbalance in cholesterol levels – raising LDL levels and increasing the risk of cardiovascular disease. How dehydration causes this is largely unknown, but dehydration is known to be especially damaging to the liver, which is where the majority of circulating cholesterol is created. This is a concern for many, because unhealthy cholesterol levels are something which you cannot easily notice or detect.
Tea/ coffee and other caffeinated drinks – Although these drinks do contain water which is hydrating, they also contain caffeine which is a diuretic. This means that it causes the kidneys to pass more water into the bladder, which has a dehydrating effect. This can make your urine look quite clear, which usually shows you are well hydrated, but in reality you may not be. These kinds of drinks should not be consumed very regularly.
Alcoholic drinks – Alcohol is also a diuretic, and has a similar effect on the body as caffeine. To remain hydrated it is important to drink water along with alcoholic drinks.
Water/ flavoured water – Flavoured water will be just as hydrating as water, although I would recommend sticking to just water because of the potential negative health effects some sweeteners can have on the body.
Fruit juice – These are also quite hydrating, but be aware of the sugar content.
Sports drinks/ isotonic drinks – These drinks are very hydrating (more so than water), and work by including minerals and sugars which cause the body to retain more water. However, due to their high sugar content, they should only really be consumed before/ during/ after sports where the sugars will be needed. Otherwise these sugars will cause fluctuating insulin levels, which, if occurs regularly, can increase the risk of type 2 diabetes.
Consuming water is often overlooked by many, but is as important, or more so, than any nutrient, and makes up 60% of our total weight. There is no exact figure for how much water you should consume, but rather you should pay close attention to what your body is telling you and drink water regularly. The body is quick to recover from dehydration, but regular or prolonged dehydration can cause a number of problems such as kidney stones, stiff joints, digestive problems and increase the risk of cardiovascular disease.
Sports drinks, or isotonic drinks are the most hydrating fluids you can drink due to their mineral and sugar content, but should only be consumed around sport. Aside from these drinks water and flavoured water are both great ways to hydrate without the sugar spikes. Limiting alcoholic drinks and caffeinated drinks, or alternating them with water, is important to keep hydration.
Image courtesy of librariesrock.