Intolerable When it comes to the many ways milk can disagree with people, lactose intolerance (a problem for up to 90% of non-Caucasians) is the tip of the iceberg. Indeed, this crampy, indigestive consequence of an intestinal shortfall of lactase, the enzyme that digests milk-sugar (lactose), may be the tip of its own iceberg.
Preliminary research suggests women who are lactose intolerant are much more likely to suffer from depression or PMS (premenstrual syndrome). The researchers speculate that undigested lactose indirectly reduces brain levels of the mellow neurotransmitter serotonin.
But it's milk's proteins that most commonly cause symptoms in the 1 to 5% of people (estimates vary widely) who are allergic. The symptoms typically are gastrointestinal, dermatologic, or ear and respiratory. They include diarrhea or constipation, acne, earaches, and a stuffy or runny nose.
Less commonly recognized are the mental and neurological symptoms.
"Milk and all that comes from milk increases melancholy," Robert Burton wrote 381 years ago in his classic The Anatomy of Melancholy. By 1976, there was enough evidence suggesting Burton was right to lead one expert to write in Annals of Allergy: "Allergies of the nervous system cause diverse behavioral disturbances, including headaches, convulsions, learning disabilities, schizophrenia and depression." That assessment was vehemently seconded in 1984 by James C. Breneman, then Chairman of the Food Allergy Committee of the American College of Allergists, in his textbook, Basics of Food Allergy.
Jonathan Brostoff, an allergist from Middlesex Hospital Medical School, speaks for many contemporary clinicians when he describes an elderly female patient whose years of depression and gastrointestinal symptoms came abruptly to an end when she dumped milk from her diet.
Scientifically, the case against milk is being made by a growing number of double-blind, placebo-controlled clinical trials. The evidence that food allergy is a common cause of ADHD (attention deficit hyperactivity disorder) and other childhood behavioural disorders is so strong and well-replicated that in 1999 the Center for Science in the Public Interest, doctors, and academics petitioned the U.S. Surgeon General to pressure the medical profession to make diet, not Ritalin, their first line of therapy.
There is also consistent evidence that as many as two-thirds of children with autism can benefit significantly, sometimes dramatically, by eliminating milk and/or gluten from their diets.
VERDICT: Cow's milk is universally regarded as one of the most potent dietary allergens. Anyone with unexplained symptoms would do well to consider avoiding it for a few weeks to see if it makes them feel better.
Back to MILK: What is the Deal?