Water, water, almost everywhere…water is a relatively simple molecule, consisting only of one oxygen and two hydrogens—H2O.
Water may be a “simple” molecule—but the properties of water are NOT so simple! The properties of water make it the “perfect” molecule to support life—and make it stand out both for life and for various other science—like the behavior of oceans and other bodies of water, how rocks, sidewalks, and plants react to freezing temperature, how to use water to heat and cool houses and other buildings, water’s properties as a solvent, the fact that it can act as an acid or a base (technically known as water’s amphoteric nature), its reactivity to other molecules and more—but let’s take this one step at a time to emphasize the versatility of water—and how that versatility can benefit health and wellness.
The Polarity of Water Plus the Ability to Form Hydrogen Bonds
In chemistry, polarity indicates an uneven charge distribution (δ+ and δ- in figure 1 represent the charge distribution in a water molecule). The polarity in water allows it to become a solvent for mineral salts and the wide range of substances required for life AND allows water to form specific types of strong interactions called hydrogen bonding. Hydrogen bonding allows water molecules to “stick together” and supports the ability of water to act as a solvent. Hydrogen bonding also allows the folding of proteins, keeping the strands of DNA together and the specific binding of antibodies to pathogens. Hydrogen bonding also results in the fact that water stores heat and cold well. This, in turn, allowed the ancient seas, where life began, to hold a relatively narrow range of temperature—temperature ideal for the chemical processes that eventually produced life—could most efficiently proceed.
The Amphoterism of Water
The term “amphoteric” indicates an ability to act as either an acid or a base in a chemical reaction. Water is amphoteric—and this means that water provides a perfect medium for the sorts of chemical reactions that are essential for life:
- Acid-base reactions
- Redox (reduction-oxidation) reactions
- Hydration and hydrolysis reactions
These reactions—and the fact that many more reactions can take place in a watery (aqueous) environment—allows life to exist in all its various and wonderful forms.
Water and Theories about the Origin of Life
Nearly all theories about the origin of life depend on water—primarily because of the properties described. The basic idea is that ancient seas—full of water, minerals, and primordial molecules—were energized in some form (e.g., lightning, solar radiation) to produce more complex molecules, including amino acids (building blocks for proteins), nucleic acids (building blocks for DNA and RNA) and more complex chains of carbon, hydrogen, and oxygen (basic building blocks for carbohydrates and other substances).
Water and the Maintenance of Life
We all know that we need water to live. But what are some of the functions of water in the body?
- Most of your body is composed of water. Water helps you:
- Flush out waste from your body. Wastes and/or electrolytes (positive or negative ions) that are soluble in water pass through the kidney (with smaller amounts passing through the skin as sweat) and are filtered, conserving the electrolytes needed and removing those that are not needed.
- Regulate your body’s temperature. As mentioned above, water helps maintain a relatively narrow temperature in your body based on its physical characteristics. Our bodies maintain a temperature within that narrow range using 4 basic methods(1): vaporization, radiation, convection, and conduction.The main regulator is the hypothalamus, located in the brain. For example, when excess temperature is produced in the body, the hypothalamus sends signals to increase sweating. When the temperature of the body is too low, the hypothalamus sends signals to the muscles to start shivering, producing heat while at the same time contracting the follicles of the skin, trapping the heat.
- Maintain brain function. The brain is mostly fat and water—when a person gets dehydrated, one of the effects is significant swelling of the brain. Loss of about 1-3%(2) of your body weight in water can alter brain function, significantly altering cognitive ability, memory, mood, and executive thinking.
- Various body substances are primarily water—examples include saliva, lubricants around joints, and digestive juices.
- Water helps limit constipation. Fiber from the diet is essential as well, but water in the stools helps with the ease of bowel movements
- Water is essential for nutrients from your diet to be properly absorbed. Most nutrients are water-soluble—because whether the nutrient source is plant or animal, those are water-dependent as well. One major class of vitamins is NOT water soluble—these are the fat-soluble vitamins such as Vitamins E, D, K, and A.
Sufficient water is needed for the proper functioning of the immune system, kidneys, GI tract, nervous system, cardiovascular system, and respiratory system. For example, we breathe out water vapor as well as carbon dioxide. Hot, dry air is much harder to breathe than colder, moister air. Water supports blood volume and blood pressure.
How Much Water Should We Drink?
One “quick and dirty” test to see if you need more water is to pinch up the loose skin on the back of your hand, forming a sort of tent. Then release it and see how long it holds the tent—if it is more than a second or two, you need more water! This is also a bit of a test of aging skin, as older skin has lost quite a bit of elasticity—keep that in mind.
What does the science say? Most experts recommend that you drink AT LEAST eight 8-ounce glasses a day—the 8×8 rule. That is about 2 liters a day. This can change for pregnant or lactating women (who should increase their water intake), for older people (who may be less capable of controlling their body temperature and at a higher risk of dehydration), young children, athletes, and those with specific conditions. This 8×8 rule also assumes healthy kidney function.
The 8×8 rule provides a basic framework— be aware that many times, you will need to drink MORE water. There are very few circumstances where you need less.
Signs of Dehydration
The Mayo Clinic(3) provides the common symptoms of dehydration in children and adults. These are:
In an infant or young child
- Dry mouth and tongue
- No tears when crying
- No wet diapers for three hours
- Sunken eyes, cheeks
- Sunken soft spot on the top of the skull
- Listlessness or irritability
In an adult
- Extreme thirst
- Less frequent urination
- Dark-colored urine
- Fatigue
- Dizziness
- Confusion
Dehydration is especially a problem in the elderly, who have a lowered ability to regulate their body’s temperature. Older adults also tend to have less body fluid, decreased kidney functions, and may have medical conditions which increase the risk of dehydration—OR be taking medication that increases their risk of dehydration. In addition to the symptoms listed above, anyone, but especially older people, may experience an increased heart rate, palpitations, confusion, fainting, vomiting, headaches, and trouble moving or walking.
Which Water is Best?
While not all “fortified water” containing various vitamins and minerals is necessarily bad, it can be problematic for some people—e.g., those with reduced kidney function, those with heart conditions where excess electrolytes may harm some, or for the elderly.
Probably the best advice is to drink pure, filtered water, preferably from your own tap and not in plastic, single-use bottles—we DO want to take care of the planet while we are taking good care of ourselves. Inexpensive filtration devices can easily provide you with clean drinking and cooking water
Takeaways
Water is, as we all know, essential to life. In many countries around the world, clean water is still often difficult to access. In the US, according to the CDC(4), “waterborne disease causes 7 million illnesses and $3 billion in healthcare costs” every year. If you have access to clean water, you may be more fortunate than you realize! Treasure it and drink enough water to sustain health and optimal wellness! Drink AT LEAST eight ounces of water 8 times a day—more if you are elderly, an athlete, in hot climates, if you are pregnant or breastfeeding—OR if you don’t “pass” the skin-tenting test! Talk to your healthcare provider if you have any specific conditions—or if your kidney function is compromised.
Resources:
- Osilla EV, Marsidi JL, Sharma S. Physiology, Temperature Regulation. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507838/. https://www.ncbi.nlm.nih.gov/books/NBK507838/
- Ganio, M., Armstrong, L., Casa, D., McDermott, B., Lee, E., Yamamoto, L., . . . Lieberman, H. (2011). Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10), 1535-1543. doi:10.1017/S0007114511002005 https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/mild-dehydration-impairs-cognitive-performance-and-mood-of-men/3388AB36B8DF73E844C9AD19271A75BF
- https://www.mayoclinic.org/diseases-conditions/dehydration/symptoms-causes/syc-20354086
- https://www.cdc.gov/ncezid/what-we-do/2021-highlights/waterborne-disease.html