With all the differences in opinion in the nutrition world, one thing that most can readily agree on is the importance of hydration. Scientific research has revealed that in humans, the brain and heart are composed of around 73% water, and the lungs are about 83% water. The skin contains approximately 64% water, muscles and kidneys are 79%, and even the skeleton is watery at around 31%.1 Further published studies have revealed that children have a higher percentage of body water than adults and that women have a lower percentage on average than men (probably related to the fact that women tend to have more body fat than men and fat has a lower percentage of water versus lean body tissues).2
Having adequate water levels in the body is an essential component for many different biochemical processes. From the blood running through the cardiovascular system and carrying all the essential nutrients and oxygen to the rest of the body, to keeping electrolyte levels in balance, to providing cushioning and lubrication to the joints, to regulating body temperature to assisting the liver and kidneys with detoxification functions, fluids are critical for proper physiological functioning.
Although most people know that there are substantial benefits to drinking water every day, many people still have questions about hydration. Things like how much water is needed each day, what’s with all the different types of water, and are there any health concerns from drinking water are common lingering questions.
How much water do I need?
Nearly everyone has heard the traditional “8 glasses a day” recommendation for adults when it comes to drinking water, and while this would likely prevent serious dehydration in the majority of adults, the truth is there really is no one-size-fits-all amount. In reality, the amount any one person needs depend on a number of variable factors relating to lifestyle, environment, and physiology. Factors like your body size and structural composition, your level of physical activity, dietary patterns including how much alcohol, coﬀee and other fluids you include in your daily consumption.
Water intake into the body comes from food and beverage ingestion as well as normal metabolic processes. A number of medical and consumer health groups have made recommendations for how much water one should consume on a daily basis:
- Harvard Medical School recommends 4-6 cups of water a day for generally healthy people3;
- The Institute of Medicine (IOM) in conjunction with The National Academies of Sciences, Engineering and Medicine suggest about 12.5 cups of fluid per day for men and 11.5 cups per day for women.4;
- It is also important to note that these recommendations include not only water intake but also other fluids, and food. As a general rule, about 20%-30% of daily fluid intake typically comes from food and the rest from liquid beverages5;
- Other groups such as the American Heart Association also follow these IOM recommendations;
- Studies conducted by the National Institutes of Health suggest between six and 10 cups per day is adequate.6
What’s up with all the different kinds of water?
Many people cite the plain, unflavored nature of water as a main reason for choosing other beverages over water. Modern technology, discovery, and good ol’ fashioned ingenuity have led to some variations that provide altho benefits of water in a satisfying way.
Fruit/Herb-Infused water: adding fresh fruits and herbs to water can be a great way to enhance the flavor without adding a ton of calories or chemicals. Simply wash, chop, and add the produce to the water then allowed to steep for at least 30 minutes (overnight is preferred). Flavor combinations range from tried and true favorites like strawberry-kiwi, cucumber-melon, and lemon-ginger to more exotic combinations like strawberry-basil, watermelon-mint, grapefruit-jalapeño, and even mojito water (lime and mint). The possibilities are endless!
Spring/Glacier Water: these types of waters are typically bottled waters that claim to be bottled at the source from either from the spring or glacier where the water originally flows. In theory, these types should be fairly clean and toxin free and may even contain any number of minerals that can support health. However, these types of water can be expensive and some spring water is raw, unfiltered and potentially untested so it could pose potential health risks.
Sparkling Water: made by infusing carbon dioxide gas into water under pressure. The result is a fizzy, bubbly drink that can be quite refreshing. Sparkling water may also contain natural minerals that enhance the health benefits of water (known as mineral water). This type of water offers the same benefits as any type of still water. They are readily available and easily found in convenience stores as well as grocery stores. Home carbonation units are also commercially available. These waters come in a variety of flavors but may also be laden with sugar or artificial sweeteners and some brands add salt as well so it is important to read the label carefully.
Alkaline Water: produced through a process known as electrolysis that splices up the atoms of hydrogen and oxygen that make up water resulting in an increase in pH of the final product. The pH of most water is around a near neutral 7.0 but alkalinized water has a higher pH, typically around 8 or 9. Since it’s more alkaline than regular tap water, it can help oﬀset a highly acidic diet that many people in developed nations are prone to eating today, potentially offering benefits like improved mineral status.6 This type of water can be purchased in bottles or it can be made using home countertop units.
Raw Water: a form of water that has not undergone any processing, filtration, or treatment. This means that it still contains its natural minerals, ions, and particles. It could also still contain bacteria, mold, or parasites as well. The general idea is that unprocessed water preserves many of the beneficial minerals and compounds. Examples of raw water include rain water, lake water, river water, and water from infiltrated wells.
Tap Water: Municipally-supplied water that comes through the pipes in a home or business. Though typically safe enough for drinking, there are concerns about contaminants such as bacteria, heavy metals like lead (as in the Flint, Michigan crisis), other types of xenobiotics (like pharmaceutical medications), as well as additives like fluoride that could potentially compromise safety. On the plus side, tap water is inexpensive and readily available in most areas.
Purified/Distilled Water: water that has been filtered and processed to remove impurities including chemicals, microorganisms, and other contaminants but certain types of purified water can also remove things like minerals which can add to the health benefits of the water.
There are a number of different techniques used to purify water and different water purification treatments are designed to remove different impurities from the water.
Are there any health concerns with drinking water?
Worldwide, some 780 million people lack regular access to safe water supplies.7 Water, sanitation and hygiene has the potential to prevent at least 9.1% of the global disease burden and 6.3% of all deaths.8 For the most part, water is among the healthiest beverages to consume (provided of course it is clean and free from contaminants that can make you sick).
It is also definitely possible to drink too much water as well. This causes a condition known as water intoxication. Water intoxication is a severe form of hyponatremia (low sodium levels in the blood) and is considered a life-threatening emergency. Symptoms of water intoxication include headaches, confusion, disorientation, nausea, voicing, muscle weakness, ramping, breathing difficulties, changes in blood pressure, drowsiness, seizures, impaired mental state, coma, and death. Water intoxication is most common in those drinking over 1.5 liters within an hour especially if they are exercising intensely, have renal failure, kidney damage, diabetes or a mental condition that affects their judgement.9 Treatment of water intoxication is a medical emergency and requires immediate medical intervention.
People with chronic health conditions like kidney disease, kidney failure, liver or heart problems should be careful about balancing their intake of water. Prescription medications can also cause water retention or increase urine output. Those on certain medications like diuretics (water pills), thyroid medications, opiate medications, and certain antidepressants should discuss with their physician how those medications impact their water needs as well.
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Andrea Pryce, N.D., received her baccalaureate degree from the University of Alaska-Fairbanks and is a 2006 graduate of Southwest College of Naturopathic Medicine in Tempe, Arizona. Following completion of her N.D. degree she went into private practice in Scottsdale, Arizona. She has a strong background in biomedical research with significant experience in both bench top and field research. She has worked as a bench top research associate performing genetic oncology assays for a major biomedical research foundation. Additionally, she served as a project coordinator for a homeopathy study co-conducted by the Southwest College Research Institute and the University of Arizona’s Arizona Center for Integrative Medicine. She maintains a research interest in the epigenetics and nutrigenomics particularly as they relate to oncology. In 2009, she moved to Florida and began working at Life Extension in Fort Lauderdale where she was Medical Editor for their monthly magazine. Dr. Pryce joined the faculty at Hawthorn University in April of 2014 and also serves on the faculty of Everglades University. She has recently joined the team at the Integrative Health Institute in Boca Raton, Florida.