Chapter 10 Water The Forgotten Nutrient The Vital

Chapter 10 Water: The Forgotten Nutrient

The Vital Functions of Water is in very cell in the body. For most adults, body weight is about 50 to 70 percent water. That equals roughly 10 to 12 gallons (38 to 46 L). Fat tissue is about 20 to 35 percent water whereas muscle is 75 percent water. Therefore, the total percentage of body weight from water depends on the ratio of fat to lean body tissue. Body fluids like saliva, blood, lymph, digestive juices, urine, and perspiration all have water as a main component.

Vital functions Facilitates chemical reactions – like the break down of carbs, fats, and protein. Transports nutrients and waste products – water is a solvent. Water can dissolve most substances. The blood carries many of these substances around the body. Lubricates surfaces – lubricants reduce friction between surfaces, like saliva and the food you eat. Regulates body temperature – Blood and perspiration are responsible for this task. {stationary bike story}

Keeping fluids in balance Cells are like balloons, they need water to maintain their shape. Too much inside can cause it to burst, to much outside can cause it to collapse. The body has mechanisms to keep the balance of water inside and outside the cells fairly constant. Water can move freely across cell membranes but is controlled by the concentration of sodium, potassium, and chloride particles inside and outside the cell. These particles are your electrolytes.

The source of the body’s water Most people need about 2 liters of water per day to replace body fluids. You meet these needs with the food you eat and the liquids you drink. Some foods are very high in water. Summer squash is about 96% water, orange juice is about 87% water, cooked pasta is about 66% water.

Bottled water versus tap water In recent years, sales of bottled water have increased greatly. Why are people buying bottled water? Is it safer? Does it taste better? It is definitely more expensive. Some people think bottled water contains magic minerals that are more healthy, this claim has never been proven. Safe clean tap water is where bottle water comes from. It is tested and then bottled. Some geographic regions may have more or less amounts of sulfur, iron, and other minerals in the tap water which will cause variances in taste.

Can you drink too much water? The answer is yes. The result is water intoxication. Drinking very large quantities of plan water can dilute the concentration of electrolytes in the extracellular fluid. If levels stay low it can cause headaches and muscle weakness. In severe cases water intoxication cause death. The greatest danger of water intoxication is in infants who are vomiting and/or have diarrhea. Their electrolyte levels are low from fluid loss and can become farther diluted when given plain water.

How is body water lost? There are several paths to water loss in the run of a day. Most fluids are lost through urine. You also loose fluids through sweat, moisture as you breath in and out, and small losses through bowel wastes. You can increase water when you are sick, or when you excerise.

Effects of water loss When you drop a small percentage of weight from water it can have large effects on the body. You will start to feel uncomfortable, at 2% you become aware of the sensation of thirst. Both the brain and stomach play a role in making you aware of thirst. If you do not replace the lost water you will become dehydrated.

More Effects of water loss At 3% blood volume decreases and the heart has to work harder to pump the blood through the body. At 10 – 11 % loss in body weight due to water loss, serious organ damage can result.

Guidelines for fluid replacement To keep your body in top condition, drink 6 – 8 cups of water per day. Some groups of people have increased need for water such as: Older adults Pregnant women Lactating women infants