Kidneys fail when the tiny capillaries that carry blood within the kidneys for purification become damage (nephrosis). As the filtering process slows down, blood and proteins pass into the urine. Water back up (a condition known as ”edema”), and the body begins to swell.

Kidney damage affect children and young adults more than older people. Most often, it's caused by inflammation following an infection such as scarlet fever. But in a small number of people, kidney damage is tied to allergies, especially if the effected person has asthma, eczema or another from of allergy.

Douglas Sandberg, M.D., professor of pediatrics at the University of Miami School of Medicine, has encountered many children whose kidney problems were linked to allergies. These problems responded to restriction of certain foods or airborne allergens. In the book, Food Allergies: New Perspectives (Charles C. Thomas, 1980), he reports a number of cases.

• Out of one group of 19 children with kidneys disorders, 17 were allergic to one or more foods. Eating those foods increased the amount of protein in their urine – a major feature of kidney malfunction. Several of the children improved significantly when their food allergies were treated.

”A Rotary Diet alone produced good results in two patients,” says Dr. Sandberg. In 11 other children, therapy also included allergy shots, which helped them to tolerate hidden foods such as milk, wheat and corn.

• Three children, age 13 to 15, were allergic to several foods (all had asthma and one had eczema). The kidneys of two of those children healed when milk was avoided. The third continued to suffer relapses. Dr. Sandberg speculates that she may have had an undetected viral infection or chemical allergy.
• A five year old boy had severe kidney inflammation, with abdominal pain and blood in his urine. To test him for allergies, he was put on a gluten free Rotary Diet, with no one food eaten more often than once in four days. Individual food were then tried. Tests showed the kidneys got worse when he ate milk, eggs and lima beans.

Eventually, Dr. Sandberg found that the boy was also allergic to a number of other foods and some chemicals, such as household cleaning solutions and insecticides, and that those allergens aggravated his kidney condition. ”With a management program including a limited Rotary Diets, environmental control measures, and food and inhalant injection therapy, (his kidneys) became normal within six months and remain so,” says Dr. Sandberg.

• A five year old girl was tested and found to be allergic to cow’s milk. Blood, urine and kidney function tests showed that her kidneys got worse after she drank cow’s milk and healed when it was avoided. Edema, or water retention, also increased visibly when she drank milk and decreased when she didn’t drink it. ”The patient was also ... sensitive to other foods, as well as to some airborne allergens, and has improved on a limited diet and food and inhalant injection therapy,” says Dr. Sandberg.

According to Dr. Sandberg, those cases strongly suggest that food allergy is one of the many causes of kidney malfunction, and that inhalant allergies also play a role.

”It would appear that these patients have an unusual degree of sensitivity to environmental agents,” says Dr. Sandberg. Allergy, he believes, may trigger a chain of events that produces different forms of kidney damage in different individuals.

Dr. Sandberg’s work follows in the wake of several studies by Japanese doctors who found that certain foods aggravated proteinuria (protein in the urine) in many people with kidney inflammation. In one group of 36 such people, foods that provoked protein loss, in order of frequency, were: milk, eggs, soybeans, pork, red beans and tuna.

Invariably, a single feeding of a food was enough to provoke trouble – which disappeared when the offending food was avoided (Clinical Ecology, Charles C. Thomas, 1976). Bedwetting, painful urination and frequent urge to urinate have also been associated with food, chemical or pollen exposures, according do Doris J. Rapp, M.D., a pediatrician and allergist in Buffalo, New York.

Kidney problems are not the sort of thing you can diagnose yourself. If you have bloody or wine colored urine, with back pain, headaches, a rundown feeling and a slight fever, see your doctor immediately. And don't be afraid to raise the question of allergies. While certain forms of kidney trouble are associated with reactions to pollen, drugs, toxins or insect bites, reactions to foods have only recently been recognized. See also Bedwetting.