In the United States we rely on milk as a basic source of calcium, and 2 cups of milk, or an equivalent amount  of  cheese  or  other  dairy  products  except butter, go a long way toward supplying all the calcium needed for the day. But milk is not the only source. Dark green leafy vegetables, such as collards, mustard greens, or turnip greens,  provide  some  calcium,  and  salmon  and  sardines supply useful amounts of it if the very tiny bones are eaten. Phosphorus. —  Phosphorus   is   necessary   for building bones and teeth. Milk, cheese, eggs, meat, legumes, nuts, whole grain cereals, and vegetables are good sources of this mineral. Iron.— Iron  carries  oxygen  in  the  blood.  The best  sources  of  iron  are  meats  (especially  liver). But  foods  from  some  plants,  such  as  dried  beans, dark  green  leafy  vegetables,  and  grains,  are  good sources  of  iron,  especially  when  eaten  along  with foods  rich  in  vitamin  C.  Vitamin  C  helps  the  body absorb iron better. Iodine.— The most important fact about iodine is that a deficiency of it can cause a goiter—a swelling of the thyroid gland. Important sources are seafoods, plants grown in the soil near the sea, and iodized salt, which is used in all Navy messes. Salt.—  Salt  is  needed  by  everyone.  A  person needs about 1 level teaspoon of salt per day and more when a person perspires a great deal. The average intake of salt is from 2 to 3 teaspoons daily, which is enough for a person drinking up to about 4 quarts of water. A person who is not getting enough salt will become weak. Many Americans eat more salt and sodium than we  need.  Salt  contains  sodium  and  is  already present in many canned or processed foods. Excess salt   contributes   to   high   blood   pressure   in   some people. Sodium  (salt)  has  been  reduced  in  AFRS recipes  to  minimum  acceptable  levels.  Sodium  can be further reduced in recipes by using the following guidelines: l l l Season food with herbs and spices instead of high-sodium items like salt, soy sauce, or steak sauce. Choose fresh rather than canned food items. Look for prepared foods that say low or reduced sodium  on  the  label. 7-3 VITAMINS.— There are about 13 vitamins that are absolutely necessary for good health. Four are called fat-soluble vitamins because they dissolve in fat. These are vitamins A, D, E, and K. They are digested and absorbed with the help of fats from the diet. These vitamins can be stored in the body for long periods of time, mostly in fatty tissue and in the liver. Nine  other  vitamins  are  called  water  soluble. They include eight B vitamins and vitamin C. These vitamins are not stored in the body very long, so you need  to  eat  foods  that  are  good  sources  of  these vitamins  every  day. A few of these vitamins are of great importance and you should know what foods provide them. Vitamin A.— This vitamin plays a very important role in eye function and in keeping the skin and mucous membranes resistant to infection. Although vitamin A occurs only in foods of animal origin, the deep yellow and  dark  green  vegetables  and  fruits  supply  a material—carotene—that  your  body  can  turn  into vitamin A. Vitamin A is found in yellow, orange, and green vegetables;  yellow  fruits;  and  in  the  fat  of  animal products like fish, milk, eggs, and liver. Both cheese made from whole milk, and margarine enriched with vitamin A supply this vitamin. Vitamin C.— Vitamin  C,  ascorbic  acid,  is  not completely understood, but it is considered important in helping to maintain the cementing material that holds body cells together. Vitamin C is needed for wound healing; for development of blood vessels, bones, teeth, and other tissues; and for minerals to be used by the body. Vitamin C is found in citrus fruits, melons, berries, leafy green vegetables, broccoli, raw cabbage, spinach, and  turnip  and  collard  greens.  Potatoes  and  sweet potatoes  provide  helpful  amounts  of  vitamin  C  and  so do  tomatoes  and  peppers. Vitamin D.—  Vitamin D is readily available in fortified milk. Sunlight enables the body to produce this vitamin if it has a chance to shine directly on the skin.  Vitamin  D  is  needed  for  using  calcium  and phosphorus to build strong bones and teeth. Vitamin D is added to most milk. It is also found in fatty fish, liver, eggs, and butter. Vitamin E.— Vitamin E helps preserve the cell tissues. Although vitamin E’s exact role in the body is not  fully  understood,  it  is  being  explored  as  an antioxidant that may retard some aspects of the aging