Water is arguably the most important of the 50-some essential nutrients that we obtain from the food we eat, yet it is commonly underconsumed by older individuals.

About 50 percent of the human body is water, and essentially all of the body’s biochemical and physiological functions depend on adequate hydration. A serious water deficiency can develop much more quickly than any other nutrient deficiency.

QUESTION: What are the symptoms of chronic dehydration?

ANSWER: They are somewhat insidious. Both physical and mental performance are adversely affected. Inadequate hydration can even affect a person’s psychological state, resulting in irritability, increased confusion, impaired short-term memory, decreased ability to focus, poor attention span and depression.

Physiological effects include decreased saliva production, which affects both food consumption and digestion and increased difficulty swallowing pills. Chronic dehydration decreases urine output and can cause constipation. Skin can become dry, and muscles can develop a chronic soreness.

Extended chronic dehydration can increase heart rate and body temperature, which in turn increases water needs because 10 percent more water is needed for each degree increase in body temperature. Other problems linked to low water consumption include compromised immune function and increased risk of urinary tract infections and kidney stones. Common consequences also include dizziness, falls, strokes, renal failure, even death.

Q: Why are people more likely to become dehydrated as they age?

A: Sense of thirst might decline with age along with a desire to decrease the number of trips to the bathroom.

Q: How much water does a person need?

A: Water needs can vary greatly depending on body size, environmental temperature and physical activity. The Institute of Medicine recommends 2.7 liters of water per day for the average adult woman and 3.7 liters for a man. Allowing for water content in food, this adds up to just over 2 liters of beverages per day (about nine 8-ounce cups) for a woman and about 3 liters (13 cups) for a man.

One of the simplest ways to monitor your hydration adequacy is to check the color of your urine. In general, its color should be more like lemonade than apple juice.

Q: Can a person drink too much water?

A: Yes. Ongoing overconsumption can excessively dilute body fluids, which can cause blood electrolyte levels to drop too low and disrupt normal fluid distribution, even adversely affecting the brain. The major indication is frequent passing of colorless urine.

Learn more at www.gotnutrients.net — a site offering nutrition and other health topics for seniors.