Lactose Intolerance

One of the most common nonallergenic food sensitivities is lactose intolerance.  Except among those of Northern European descent, lactose intolerance is a condition suffered by almost 100% of the people in many areas of the world.  In the United States, 95% of Orientals are lactose intolerant, 75% of blacks, 60% of native Americans, and from 2 to 24% of Caucasians, depending on the group studied. Lactose is the naturally-occurring sugar found in all milk (human, cow, goat, etc.).  It's made up of two sugars coupled together glucose and galactose.  In the scientific community it's known as a "disaccharide".  An enzyme in the intestine called lactase is necessary to split the glucose and galactose apart in order to digest lactose.

Most adults lack the enzyme, lactase, to break down lactose.  Instead, lactose is broken down by bacteria in the lower intestines.  The bacterial wastes combine with sugars to ferment into gas and toxins causing bloating and cramps.

Incidence

Since lactose is found in mother's milk, almost all infants of nursing age are able to digest it.  But past weaning and with increasing age, progressively fewer children retain this ability.  One study of black children found lactose intolerance in 11% of four- to five-year-olds, 50% of six- to seven-year-olds, and 72% of eight- to nine-year-olds.  Other studies have found close to 85% lactose malabsorption among black teenagers.  Mexican-American children studied were 18% intolerant to lactose among two- to five-year-olds and increased to 56% among teenagers.  It's usually rare among North American white children under six years of age, but increases to 30% in adolescents.

"Most formula-fed infants developed symptoms of allergic rejection to cow milk proteins before one month of age.  About 50-70% experienced rashes or other skin symptoms, 50-60% gastrointestinal symptoms, and 20-30% respiratory symptoms.  The recommended therapy is to avoid cow's milk." [Pediatric-Allergy-Immunology, August, 1994]

Signs and Symptoms

Not all individuals with proven lactose intolerance have symptoms, particularly if only small quantities of milk are consumed.  When symptoms do occur, however, they can include gas, abdominal distention, diarrhea, and recurrent abdominal pain, especially among children.  Infrequently, severe cases of lactose intolerance in children have been shown to cause damage to the lining of the intestine and severe diarrhea.

Although lactose intolerance is a good example of a nonallergenic yet food-sensitive condition, there can be an overlap of the two.  People with a true milk allergy suffer both the intestinal and systemic symptoms and may have problems including nasal congesting, headache, urinary frequency, hives and protein loss in the urine.  They can also have a food sensitivity.  Of 24 milk-allergic individuals studied, half were found to be lactose intolerant.

Diagnosis and Tests

These various reactions to milk illustrate the importance of distinguishing types of food sensitivity, in this case true allergy versus intolerance due to enzyme deficiency.

Treatment and Prevention

Not using milk is the preferred treatment option in either case.  Adding sufficient acidophilus bacteria or commercial preparations of the enzyme lactose to milk-containing meals will prevent symptoms and improve nutrient absorption for individuals with lactose intolerance, but not for those allergic to milk.  Conversely, milk allergy can sometimes be treated by desensitization.  This is a procedure that is still somewhat mysterious; it introduces a very small dose of an allergic substance into the body and blocks the body's response to the allergy.  The process doesn't cure the allergy or help lactose intolerance.

"Lactose malabsorption and lactase deficiency are chronic organic pathologic conditions characterized by abdominal pain and distention, flatulence, and the passage of loose, watery stools.  Once correct diagnosis is established, introduction of a lactose-free dietary regime relieves symptoms in most patients who remain largely unaware of the relationship between food intake and symptoms." [J Clin Gastroenterol, 1999 Apr, 28:3]

There are, of course, many good reasons to avoid milk, including:

• "In reality, cow's milk, especially processed cow's milk, has been linked to a variety of health problems, including: mucous production, hemoglobin loss, childhood diabetes, heart disease, atherosclerosis, arthritis, kidney stones, mood swings, depression, irritability, allergies..." [Townsend Medical Letter, May, 1995]
• Milk is linked to Crohn's disease.  "Mycobacterium paratuberculosis is capable of surviving commercial pasteurization." [Applied and Environmental Microbiology: 64(3), Mar 1998] ...  "Mycobacterium paratuberculosis (bacteria not killed by pasteurization) RNA was found in 100% of Crohn's disease patients, compared with 0% of controls." [D.  Mishina, Proceedings National Academy of Sciences USA :93: September, 1996]
• Diabetes.  "These new studies, and more than 20 well-documented previous ones, have prompted one researcher to say the link between milk and juvenile diabetes is 'very solid'." [Diabetes Care 1994; p.17]
• "Cow's milk has become a point of controversy among doctors and nutritionists.  There was a time when it was considered very desirable, but research has forced us to rethink this recommendation ...  dairy products contribute to a surprising number of health problems (including) chronic ear problems..." [Benjamin Spock, M.D., "Child Care", 7th Edition]
• Heart Disease.  "Milk and milk products gave the highest correlation coefficient to heart disease, while sugar, animal proteins and animal fats came in second, third, and fourth, respectively." [A Survey of Mortality Rates and Food Consumption Statistics of 24 Countries, Medical Hypothesis 7: pp.907-918, 1981]
• Osteoporosis.  "Consumption of dairy products, particularly at age 20 years, was associated with an increased risk of hip fractures ...  metabolism of dietary protein causes increased urinary excretion of calcium." [American Journal of Epidemiology 1994; p.139]
• Pesticide ingestion.  "A 1988 FDA survey of milk samples from grocery stores in 10 cities found that 73% of the samples contained pesticide residues." [Environmental Contamination and Toxicology, 1991; p.47]
• "The National Dairy Board's Slogan, 'Milk.  It does a body good,' sounds a little hollow these days." [Scientific American, October, 1992]

It is interesting to consider that no non-human animals naturally drink milk beyond weaning; nor do any animals naturally drink the milk of other species.  "Overall, about 75% of the world's population, including 25% of those in the U.S., lose their lactase enzymes after weaning." [J.  of the American Dietetic Assoc.  1996]