Quiz 9: Water and Minerals
Most of the iron present in the body is in the form of hemoglobin in the blood. A small portion of iron is present in liver, spleen, and bone marrow in the form of ferritin. Iron consumed through the diet is classified into heme and nonheme iron depending on the structure and bioavailability of the iron. Heme iron has a higher bioavailability of 15 to 35 percent compared to 5 to 15 percent of it in nonheme iron. The iron available for absorption in the food is referred to as elemental iron. Elemental iron in food is provided by both heme as well as nonheme iron, in different proportions. The food products such as fruits, vegetables, and grains including cereals contain no heme iron. The iron contained in these sources is 100% nonheme iron. Hence, options a, c, and d would be incorrect. Heme iron is derived from hemoglobin and myoglobin. Hence, it is possible to have heme iron only from animal sources such as meat, fish, and poultry. Hence, the option would be the correct option.
Water is required by the body for carrying out the regular maintenance processes in the body. Body produces 250 to 350 mL (1 to 1 ½ cups) of water everyday as by-product of the chemical reactions used to metabolize energy. It loses 100 mL (0.4 cup) through feces, 300 mL (1.25 cups) through the lungs due to respiration, 600 mL (2.5 cups) through perspiration, and 1950 mL (8.25 cups) through urine. This water needs to be replenished by the body. The total intake of water for the adult women must be 2.7 liters (11 cups) and for the adult man must be 3.7 liters (13 cups). Alcohol is a vasopressin inhibitor. Vasopressin shows anti-diuretic action. Inhibition of vasopressin causes alcohol to act as a diuretic. This causes removal of kidneys, ureters, and bladder to drain the water from the body at a much a quicker rate. Alcohol consumption can increase the need for water. The humidity at sea level is more than that at high altitudes. This influences the loss of water through the body including through perspiration and urination. Also, since the oxygen at high altitudes is less, the respiration rate increases. This increases the losses through respiration. Usually the water lost through lung respiration is 300 mL. At altitudes, the water loss could be twice as much. Higher altitudes from sea can increase the need for water. Fruits and vegetables contain 80% water. Meat contains at least 50% of water. Milk contains more than 85% water. These can provide water in the average person's diet.
Most of the dietary chlorine is in the form of chloride. The major source of chlorine in food is in the form of ionic chloride in common salt. Only a tenth of the chloride exists intracellularly compared to that present extracellularly. Chloride is a negatively charged ion which is formed when a neutral atom of chlorine obtains an electron. The intestine absorbs chloride and not chlorine from the food. Most of it is consumed in the form sodium chloride as common salt. Hence, the options b, c, and d would be incorrect. Chloride is an anion. Apart from playing a major role in the fluid balance and distribution, it is responsible for the formation of hydrochloric acid in the stomach. Being a negatively charged ion, it can bond with hydrogen to form hydrochloric acid.Hence, the option would be the correct option.