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Do we really need 8 cups of water?
As seen on BCTV September 24/02
While we do need water to live, it does not always have to be from the tap. There are a variety of sources of water in our diet and each person has different requirements.
In our bodies water helps remove of waste, acts as a solvent for nutrients, it is involved in metabolic reactions, it helps maintain blood volume and regulates body temperature.
65% of our body is made up of water
We lose water daily through sweat, breath and urinary and fecal losses for a total average loss of 2-2 1/2 liters per day.
Early Symptoms of Dehydration include low energy, dry mouth, poor concentration, blurry vision, reduced performance in sport.
There are a variety of sources of water in the diet –
Fruit and vegetables are made up of 90% water
Meat/fish/poultry/cheese are up to 50% water
Milk/juice/spritzers are almost 100% water
Pop/coffee/tea/alcohol contain water but also some dehydrating factors such as caffeine, alcohol and sugar
Soup varies on water content depending on the type of soup, also contains salt which can be dehydrating
Metabolism also produces water as a byproduct of energy production (ATP)
Factors that affect water requirements:
Higher dietary intake of salt and sugar increase fluid requirements
Higher intake of caffeine and alcohol increase fluid requirements
Environmental temperature – Summer heat increases sweat production and water losses
Activity – increased sweat production and resultant loss of body water
If we are eating a variety of foods, emphasizing vegetables and fruit and drinking a variety of fluids including soup, milk and juice it may be possible to meet our fluid needs without pure water. However, many Canadians do not meet the recommended intake of 5-10 servings of vegetables and fruit/day (1/2 cup = 1 serving). Some individuals also depend on prepackaged and processed foods that contain salt and sugar – both of which lead to increased urinary output (water loss through urine).
Tip: Look at your diet and assess your intake of fluid containing foods. For a rough estimate count 1/2 cup (1 tennis ball size) of fruit or vegetable as 1/2 cup water
1 cup pure fruit juice, milk, spritzer, weak-medium strength tea, low sodium soup or sparkling water as 1 cup
1 cup coffee or mixed alcoholic beverage as 1/2 cup (taking into consideration some loss due to the diuretic effect of caffeine and alcohol
If you had 5 servings of fruit and vegetables, 1 cup coffee, 1 cup juice and 1 cup milk you would have ingested 5 cups of fluid. If the average requirement is 8 cups then you only need 3 cups of water. If you exercised for an hour you could need 12 or more cups in total.
It is also important to look at the quality of your food choices. If you think that drinking pop and coffee instead of water is a good way to get your fluids, think again. Pop contains phosphates that can affect bone health and are void of important nutrients for good health such as vitamins and minerals. If you are having coffee, what are you putting in it? Cream and sugar? Is your coffee replacing a more nutritious choice such as milk, soymilk or pure fruit juice? The caffeine and both pop and coffee can also reduce the absorptions of certain nutrients such as calcium and iron.
Pay attention to your internal cue for thirst. Some people misinterpret thirst for hunger and eat instead of drinking. Many people have been overriding their thirst mechanism and now are not in tuned with their cues. During exercise our thirst mechanism is blunted so it is important to drink some water (1/3 -1/2 cup every 15-20 minutes during intense exercise) even if we don’t feel thirsty. Replace each pound of body weight lost during exercise with at least 2 cups of water.
A major concern for athletes competing in endurance sports is the fact that they are also losing salt in sweat. For these individuals, replacing their electrolytes (potassium and sodium) during exercise is also important in order to prevent hyponatremia (low sodium in the blood). This can be done with a sports drink or by adding ΒΌ tsp salt to orange juice.
Bottom Line: Don’t stop drinking water because of all the information you hear on the media. Look at your own personal intake of water through various foods and fluids and top it off with a glass of calorie-free water. Remember, if you are active or in the sunshine drink more and if you eat a really sweet or salty food have a fruit or glass of water to compensate.
Watch for the Eating for Energy segment on BCTV’s Noon News Hour!