Kidney are bean-shaped organs, lying below the waist on either side of the vertebrae, are only about four inches long, two inches wide, and an inch thick. Yet arranged in orderly precision around the outer portion are millions of tiny balls of capillaries, or glomeruli–the Latin plural for ball. Long, slender tubes, or tubules, curve around each miniature ball, then after winding like hairpin loops on a mountain road, converge into ever larger tubules until all combine into a single canal, the ureter, leading to the bladder. Capillaries carrying fresh blood surround each tubule; and the whole is held together by connective tissue. Thus incredible miles of capillaries and tubes form the working mechanism of the kidneys.

An adult has about 12 quarts of blood, yet because of continuous circulation, the kidneys filter approximately 4,000 quarts daily. Elevated blood pressure in the capillary balls forces protein-free plasma into the tiny tubules; and as this plasma trickles down its long path, water and nutrients are reabsorbed into surrounding capillaries much as foods are absorbed from the digestive tract. In this manner, healthy kidneys prevent dehydration, throw off wastes (largely urea from the breakdown of worn-out cells), and keep the body from becoming acid or alkaline.

Infections of the kidneys and bladder. As with other infections, inflammations of the kidneys and urinary bladder, known as pyelitis and cystitis respectively, call for an anti-stress diet and increased amounts of all nutrients needed to build resistance. Because a highly acid urine, produced by eating meats, eggs, milk, cheese, breads, and cereals, retards bacterial growth, vegetables, fruits, and especially citrus juices should be largely avoided for a week or more.

During cystitis, ulcers sometimes cover the walls of the bladder, and unless vitamin E is kept unusually adequate, massive scarring can form, contract, and drastically reduce its capacity for storing urine.

Problems With Voiding

Inability to control the passing of urine, or "bed-wetting," has been produced in volunteers by a deficiency of magnesium. Conversely, inability to pass urine occurs when the blood potassium becomes low following severe stress; and it has been produced in animals by diets deficient in vitamin B2 or pantothenic acid. Supplying the missing nutrients rectifies the situation.

Bright's Disease

The term Bright's disease is applied to many types of kidney damage, including nephritis, an acute inflammation most often affecting children but usually not involving bacteria. Blood albumin, antibodies (gamma globulins), and millions of dead cells are lost in the urine, and the blood serum is often milky with fat and cholesterol. This disease can become progressively worse and result in death, or it may subside into a chronic stage where the patient gets better but not often well.

Nephrosis refers to less acute kidney damage generally affecting older people. Its onset is usually gradual, though puffiness under the eyes, frequent urination, perhaps headaches and excessive blood cholesterol may precede it for years. Fatty deposits in the arteries and tiny tubules decrease the blood supply to the kidneys, the amount of nutrients reabsorbed, and the quantity of urine excreted. Entire areas may be filled with dead cells and scar tissue, yet recovery is still possible. Usually when urine formation is severely inhibited, highly toxic urea cannot be excreted and may cause fatal uremia poisoning.

Numerous other names given to kidney disease refer to the part of the organ most damaged and are transitional phases of the same abnormality.

Experimentally Produced Kidney Diseases

Nephritis has been produced in many species of animals by diets deficient in the B vitamin cholin. The coils of capillaries are particularly damaged, severe hemorrhages occur, blood lecithin drops far below normal, deposits of cholesterol and fats become so excessive that urine formation is decreased, circulation inhibited, and so much albumin is lost in the urine that dropsy results. Vitamin B12, folic acid, or the amino acid methionine alone can correct the dropsy, but only cholin can stop the hemorrhaging.

When diets high in calories, especially alcohol or refined sugar, are given, the need for cholin is markedly increased and kidney damage becomes much more severe. If the diet is low in both cholin and protein, such acute dropsy develops that digestion, circulation, and other body functions are interfered with. Although cholin deficiency also harms the liver, kidney disease is produced long before liver damage can be detected.

Cholin can be made from methionine, but when growth is rapid, the building of body protein has priority and leaves none of the amino acid to be changed into the vitamin. For this reason, the young of any species is particularly susceptible to nephritis. Even when adequate protein is given, young, rapidly growing rats on a cholin-deficient diet develop nephritis within four to seven days, and most of them soon die, their fat-filled kidneys swollen, discolored, and containing large areas of dead tissue. Because the illness stops growth and decreases the need for cholin and methionine, the kidneys of the animals which live gradually improve.

Like the animals, a rapidly growing child not given cholin may be unable to obtain enough from methionine. When methionine is radioactively labeled and injected into humans, it is recovered not as cholin but as lecithin. The cause of the fatty deposits that damage the kidney appears to be identical to that which induces atherosclerosis. In Bright's disease the blood lecithin decreases in proportion to the severity of the illness, cholesterol is extremely high, and milky blood serum caused by fatty substances is particularly characteristic; when lecithin is given these conditions are rectified.

If cholin is added to an otherwise adequate diet, experimental nephritis is quickly corrected. Calves receiving no cholin die within seven days of severe hemorrhaging nephritis. Other calves, kept on the same diet but given 1,000 milligrams of cholin as late as the sixth day, make "dramatic improvement" within 24 hours. Giving cholin with inositol or as lecithin, however, is much more effective than cholin alone.

Though the experimentally produced nephritis, "strikingly similar to the disease seen in man," is corrected as soon as cholin is added to the diet, this vitamin is rarely given to humans with kidney diseases. Yet more than half of 102 people with fatty livers, recognized as a cholin deficiency, had high blood urea and albumin in the urine, showing mild nephrosis, which quickly disappeared when cholin was given with an adequate diet. In another study of 48 persons, the blood pressure fell to normal and albumin cleared from the urine when cholin was taken.