Water is essential for life because it helps regulate body temperature, lubricate joints, maintain blood volume, flush toxins from the body, and transport nutrients inside the body. An adult's body is about 55% to 60% water; in children and babies, the percentage is even higher.
A lack of water intake, or increased water loss (such as through sweating), results in dehydration, which can be dangerous and even fatal.
Water Nutrition Facts
One cup (8 fluid ounces or 237g) of water provides 0 calories, 0g protein, 0g carbohydrates, and 0g fat. Water is an excellent source of hydration and may contain numerous minerals including calcium, fluoride, iron, potassium, or sodium. The following water nutrition information is provided by the USDA.
- Calories: 0
- Fat: 0g
- Sodium: 9.5mg
- Carbohydrates: 0g
- Fiber: 0g
- Sugars: 0g
- Protein: 0g
Carbs
Drinking water does not contain carbohydrates, sugar, fiber, or starches unless it has added flavorings such as juice.
Fat
Drinking water is fat-free.
Protein
Drinking water is not a source of protein.
Vitamins and Minerals
Some water contains minerals such as calcium, fluoride, iron, potassium, or sodium, depending on the source and whether or not it's filtered or distilled. Some flavored or enhanced water products contain added vitamins or electrolytes.
Health Benefits of Water
Drinking plenty of water daily will ensure you get enough for essential body functions. Drinking water helps regulate body temperature and keep you cool in hot environments.
The Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine recommends adult women consume around 91 ounces of water daily (2.7 liters or 11.5 cups) and men get about 125 ounces (3.7 liters or 15.5 cups). This includes all water, beverages you drink, and foods you eat.
Prevents Dehydration
Some research indicates that even mild levels of dehydration can impair physical function, or at least make you feel like it requires more effort to do things. Dehydration can sometimes trigger headaches, too.
As long as you're healthy, thirst can be your guide, so you should drink more water when thirsty. It's possible that thirst mechanisms don't work as well in older people or during strenuous exercise.
You'll need more water and should drink before you are thirsty if you're in hot temperatures or you're physically active, like during hard exercise or a labor-intensive job. Pregnant or nursing women need extra water as well.
Regulates Body Temperature
One of water's important functions in the body is to regulate temperature. For example, sweating is an efficient way to cool the body when it's too hot.
Can Improve Mood
Mild levels of dehydration can also affect your cognitive function and mood, so drinking enough water is also good for your brain function. One study showed that being dehydrated by just 2% impaired some cognitive functions.
Removes Waste
The kidneys use water to produce urine, helping the body rid itself of toxic substances. Staying hydrated helps the kidneys work more efficiently.
Improves Digestion
Water is also important to the functioning of the gastrointestinal tract; the stomach needs water to create digestive secretions. Insufficient hydration can also cause constipation.
Reduces Exercise-Induced Asthma
Strong clinical evidence shows low fluid intake is associated with exercise-induced asthma, in which physical activity triggers symptoms of asthma, such as wheezing and shortness of breath.
Helps With Weight Management
Since water is calorie-free, drinking water can help you lose or maintain weight when you drink it in place of high-calorie beverages. It can also help you feel full so you consume fewer calories.
Allergies
Water allergy is very rare, but it is possible. The condition is called aquagenic urticaria. People with it develop itchy hives when drinking water or coming into contact with it. Since water is essential for life, treatment is required to manage this condition.
Adverse Effects
It is possible to drink too much water, but under normal circumstances, it is unlikely. Drinking way too much water too quickly leads to a condition called hyponatremia or "water intoxication." When that happens, the sodium levels in your blood drop way too fast and make you sick.
Hyponatremia is a medical emergency and can be fatal. The condition can occur in marathon runners and other endurance athletes who drink a lot of water without replacing the salt they are losing through sweat.
Water Varieties
You can get drinking water from your faucet (tap water), or buy it bottled. Bottled water is regulated by the Food and Drug Administration and must be as clean and safe as tap water. It may be carbonated ("sparkling"), distilled, purified, or filtered, or may contain minerals from an underground source. Some bottled waters have additives such as oxygen or protein.
Adding a few drops of flavoring or a small packet of crystals doesn't transform your water into something else or add significant calories. In fact, if you don't like the taste of plain water, adding a bit of flavoring is a good way to want to drink more.
Just about everything with fluid counts as water. Even dry foods like toast or crackers have a little bit of water. Some foods, such as cucumbers and watermelon, have more water than others.
About 20% of your water intake comes from the foods you eat (this increases if you typically eat a lot of fruits and vegetables), and about 80% comes directly from fluids including water, milk, soft drinks, juice, and even caffeinated beverages such as coffee and tea.
Storage and Food Safety
In general, tap water in the United States is very safe to drink. It is regulated by the Environmental Protection Agency (EPA) and tested frequently to make sure it is free of bacteria and contaminants.
If you get your drinking water from a private well, it is important that you have it tested to make sure it is safe. The Centers for Disease Control and Prevention (CDC) recommends testing well water at least once a year. Your local health department or county government can help you find a licensed testing laboratory.
Bottled water may come with a sell-by date, but it will generally last a very long time. After about a year, the taste may change slightly, but the water will still be safe to drink. If you're drinking your own tap water, use a clean glass or stainless steel water bottle (the trendy Stanley Tumbler works well), and wash it with soap and hot water every other use.
How to Prepare Water
It's perfectly OK to enhance the flavor of water so it's more palatable to you. Aside from commercial sugar-free flavorings, DIY by adding a slice or two of lemon or lime to a cold glass of water. Or add sliced strawberries, cucumber, or fresh herbs. When the weather is cold and you want something warm, make herbal tea or hot water with lemon. If it's the fizz you crave, try sparkling water.