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In blog post of 9/29/2014: So, what should you eat for optimal health?, I listed the seven basic principles I have extracted from the many diet books and resources I have studied. These principles are:

  1. What you eat, how much you eat and when you eat, all matter
  2. Eat clean
  3. Eat lots of vegetables and fruits
  4. Use only healthy fats and fat sources
  5. Incorporate sufficient proteins in your diet
  6. Best beverage to drink is pure water
  7. Add or subtract specific foods based on your personal needs

In the last posts, we discussed the first five of these principles. Today, let’s focus on the fifth principle: Best beverage to drink is pure water. And, as usual without any fluff stuff, let’s get to it.

I am sure by now you have heard over and over again, “Keep yourself hydrated.” Or “Drink plenty of water”. But why do we need to keep hydrated?

Water is the solvent for biochemical reactions and has unique physical properties (e.g., high specific heat) to absorb metabolic heat within the body.

Water is also essential for maintaining vascular volume and serves as the medium for transport within the body by supplying nutrients and removing waste. In addition, cell hydration has been has been suggested to be an important signal to regulate cell metabolism and gene expression.

Water is the largest component of human bodies. About 70% of our body weight is water. To maintain homeostasis, i.e., equilibrium in our biology, we need to replenish the daily water loss. Water loss comes from breathing out, sweating, urination and excretion.

You may have noticed feeling sluggish if you are dehydrated. In fact dehydration can bring on a variety of symptoms:

Mild to moderate dehydration is likely to cause:

  • Dry, sticky mouth
  • Sleepiness or tiredness — children are likely to be less active than usual
  • Thirst
  • Decreased urine output
  • No wet diapers for three hours for infants
  • Few or no tears when crying
  • Dry skin
  • Headache
  • Constipation
  • Dizziness or lightheadedness

Severe dehydration, a medical emergency, can cause:

  • Extreme thirst
  • Extreme fussiness or sleepiness in infants and children; irritability and confusion in adults
  • Very dry mouth, skin and mucous membranes
  • Little or no urination — any urine that is produced will be darker than normal
  • Sunken eyes
  • Shriveled and dry skin that lacks elasticity and doesn’t “bounce back” when pinched into a fold
  • In infants, sunken fontanels — the soft spots on the top of a baby’s head
  • Low blood pressure
  • Rapid heartbeat
  • Rapid breathing
  • No tears when crying
  • Fever
  • In the most serious cases, delirium or unconsciousness

Many diseases are linked to dehydration. These include kidney stones, gall stones, bladder, colon and other cancers, arrhythmias, blood clots, Mitral Valve Prolapse, and Osteoporosis.

How much water do we need?

So, given that we need to keep body hydrated, that is, replace the H2O we lose daily with equivalent amount of H2O, how much water do we need everyday?

Institute of Medicine of the National Academies report on Dietary Reference Intake for Water, Potassium, Sodium, Chloride and Sulfate recommends the following DAILY Recommended intakes for water for different age groups:

For Children

1–3 years         1.3 L total; 0.9 L (4 cups) as beverages

4–8 years         1.7 L total; 1.2 L (5 cups) as beverages

For Males

9–13 years       2.4 L total; 1.8 L (8 cups) as beverages

14–18 years     3.3 L total; 2.6 L (11 cups) as beverages

Over 19 years   3.7 L total; 3.0 L (13 cups) as beverages

 For Females

9–13 years       2.1 L/day of total water; 1.6 L (7 cups)

14–18 years     2.3 L/day of total water; 1.8 L (8 cups)

Over 19 years   2.7 L total; 2.2 L (9 cups) as beverages

Pregnant and Lactating women are exception and will need even more for each respective age group.

Can you drink too much water?

In very unusual circumstances, excess consumption of water and low sodium intake may lead to excess body water, resulting in hyponatremia and cellular edema. This condition comes from body getting too low in sodium rather than too much water.

What are the sources for water?

So, given that we need to keep body hydrated, that is replace the H2O we lose daily with equivalent amount of H2O, where do we get it from and where should we get it from?

Well first of all we do get a little bit of it when the body oxidizes hydrogen-containing substances during metabolism or energy production cycle. This water, called Metabolic Water is generally enough to offset the water we breathe out as vapors.

Rest of the water comes from what we consume, i.e., the stuff that crosses our lips. Of course, if you are taking nutrients intravenously (as saline solution or glucose solution in a hospital) that also counts.

All foods, especially, fruits and vegetables contain water. Beverages Coffees, tea, ice tea, milk, sodas, juices, beer all contain water. Institute of Medicine of the National Academies report on Dietary Reference Intake for Water, Potassium, Sodium, Chloride and Sulfate has the following table on daily water intake from a 2,200 calories daily diet. (Please click on the graphic below if it is not readable)


NOTE: This diet meets the Adequate Intake or the Recommended Dietary Allowance for adult men and women for all nutrients for which one has been established (for fiber, it meets the ratio of 14 g/1,000 kcal) and provides energy nutrients within the acceptable macronutrient distribution ranges. Nutrient totals may not equal the sum of the parts, due to rounding. Vegetables prepared without salt.

Food composition data: U.S. Department of Agriculture, Agricultural Research Service, Nutrient Database for Standard Reference, Release 16.


So, what is the optimal source of hydration?

When I came to the US, 37 years ago, I somehow created associations that beer is the only drink that really goes with pizza and at McDonald’s you always ate hamburger with French fries and Coke. I don’t know how those associations happened, since I did not eat pizzas or McDonald’s’ hamburgers before coming to the US. I guess it was from watching all those TV commercials or just mimicking what everyone else around me was doing.   In fact, it was four years later that watching a friend of mine, I learned that you could actually ask for water at McDonalds.

Fruits and vegetables are definitely good sources for water. Other than getting water from food, what about beverages? Are all beverages, coffees, tea, ice tea, milk, sodas, juices, beer, and wine as good a source of water?

Given the western culture, the answer could be quite confusing.

In research literature, there seems to be some controversy about whether coffee and alcohol are only transitional diuretics or permanent diuretics. Some say that caffeine and alcohol actually cause dehydration. Others disagree.

And, the citrus industry convinced us over two decades ago that “orange juice is not just for breakfast anymore”, so we should be  drinking that all day long.

Coke and Pepsi, of course, promise us sex and happiness.

“Got Milk” teaches us that all the hip people drink milk and it is a fun drink and of course, it is the only source of calcium out there.

Beer is the real beverage to quench thirst, besides it gets us sex and popularity.

Wine is definitely one for sophisticated people and of course makes us live longer.

All this just to get people to drink their stuff to get hydrated! So, what is one to do?

I tend to agree with Joe Dillon, who likes to say, “Just because it is wet, does not mean it will hydrate you.”

Bottom Line

My take on all this is to ask the basic question: when I drink a beverage for hydration, do I want the collateral stuff?

Whether it is caffeine, or alcohol, or sugars or artificial sweeteners, or artificial colors, or whatever else,  if I do want the collateral stuff, then the particular beverage at that moment is an acceptable, desirable or even a good source of hydration. If not, I rather just drink water.

And, in most of the situations, when I am looking to hydrate myself, I rather go directly to the source of hydration that my body is ultimately looking for, which, of course, is Water.

What do you think of this approach?

Do you feel that this simplifies the confusion about water and hydration?

Do you see a hole in this approach? What would you do differently?