Q. I read somewhere that water is a nutrient. Please explain.

A.  Commonly a nutrient is defined as a substance that nourishes a living being. Water as a nutrient, nourishes not only living beings but also living plants. Some sources list water as one of six main types of nutrients that the body acquires from food, the other five being carbohydrates (including fiber), proteins, fats, vitamins, and minerals. Of all these nutrients, lack of water is the most immediate concern for survival, because dehydration can become life threatening in a matter of days. Typically you can go longer without food than you can without water. According to Claude Piantadosi of Duke University, you can go about 100 hours without drinking water if the temperature outdoors is average. If it’s cooler, you can go a little longer. If you are exposed to direct sunlight, it’s less. Water is so important that dehydration causing a loss of more than 10 percent of your body weight is considered a medical emergency.