|Cow's Milk Allergy||Lactose Intolerance|
|Cause||abnormal reaction of the immune system to milk proteins||not enough of the enzyme lactase needed by the digestive system to breakdown all the milk sugar lactose|
|Age||usually starts in early infancy, rarely after twelve months of age||very rare in the first two years of life|
|Diagnosis||made by a qualified medical practitioner based on
a detailed history and the following possible tests:
skin prick test
blood tests (total IgE or RAST)
food challenge, open or double-blind not done where there is a history of anaphylaxis
|made by a qualified medical practitioner based on
a detailed history and the following possible tests:
* breath hydrogen excretion after a lactose challenge
|Symptoms||(affect can be immediate or delayed):
digestion: nausea, vomiting, diarrhea, stomach cramps
skin: hives, eczema, swelling
airways: runny nose, nasal congestion, wheezing, coughing
anaphylaxis: rare, acute, sometimes overwhelming reaction of the immune system.
**Can be life-threatening
|affects digestion only:
|Treatment||eliminate foods containing cow's
milk protein, since a very small amount of milk protein may bring on symptoms
breast-feed, if possible and for as long as possible (mother may have to moderate her own intake of milk products)
use hypoallergenic infant formulas (test for tolerance)
|symptoms are generally
dose-dependent,; small amounts of lactose containing foods (ex. 125 mL milk)
are often well tolerated
hard cheese and yogurt are well tolerated
use commercially available lactase (ex. Lactaid drops or pills) when eating lactose containing foods
Cow's Milk Allergy
Milk allergy results from a hypersensitivity of the immune system to the protein in cow's milk. Symptoms can occur within minutes or hours of contact with milk and can range from mild to severe reactions. For a those with severe allergies, they must completely eliminate cow's milk proteins from their diet. Fortunately, children who have a milk allergy usually "outgrow" it, unlike lactose intolerance.
Plan to breast-feed since it may lessen the chance or delay the onset of a milk allergy. The nursing mother with a milk allergic infant may find it necessary to limit her own consumption of milk products. When breast feeding is not an option, be cautious in selecting formula. At this time, there is no milk substitute on the market that is ideal for every child allergic to milk protein. Some milk allergic children become allergic to soy and goat's milk protein. The best substitutes seem to be formulas called "casein hydrolysates" (Nutramigen, Pregestimil, Alimentum) which are made from pre-digested protein.
Solid Food: What and When?
Take your time introducing solid food to your infant. When the baby is 4-6 months old, begin with iron-enriched, single grain infant cereals like rice or barley. Slowly add small spoonfuls of pureed single vegetables (except corn) at the rate of one per week. Move on to pureed fruit (excluding citrus) introducing each in the same way as with the vegetables. The move on to pureed meat. Start with chicken, turkey, and lamb since these are the least likely to cause an allergic reaction. When the child is at least 12 months old, you can try cooked egg yolk which is less allergy-prone than the egg white.
Don't Keep It a Secret
Tell everyone who may have contact with your child about the allergy. A letter from your doctor explaining the diagnosis may be helpful in convincing the skeptics of its seriousness. Carry prescribed medicines with you at all times and provide your child with a medical bracelet if the allergy is severe. Have your allergist reassess your child regularly. Remember the good news: elimination of foods containing milk protein may help in bringing the allergy to a quick end.
Check Labels Carefully
All prepared food must carry a label listing the ingredients. When in doubt about any food ingredients call the manufacturer. Kosher stores and bakeries are good sources for many milk-free foods. The "parve" or "pareve" means that the food contains neither meat nor milk.
Some food ingredients that indicate or may indicate the presence of milk protein:
|ammonium caseinate||high protein flour||milk solids|
|artificial butter flavor||hydrolyzed casein||natural flavoring|
|butter solids/fat||hydrolyzed milk protein||Opta (fat replacer)|
|calcium caseinate||lactalbumin||potassium caseinate|
|caramel colour||lactalbumin phosphate||rennet casein|
|caramel flavouring||lactate||Simplesse (fat replacer)|
|delactosed whey||lactose||sour cream solids|
|deminernalized whey||magnesium caseinate||sour milk solids|
|dried milk||milk derivative||whey|
|dried milk solids||milk fat||whey protein concentrate|
some foods that contain or may contain milk protein:
|baked goods||deli meats||milk|
|chocolate||Half & Half||seasoning|
|cream soups||ice cream||sour cream|
What is Lactose Intolerance?
Lactose intolerance is the inability to digest significant amounts of lactose, the predominant sugar of milk. This inability results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. See figure 1. Lactase breaks down milk sugar into simpler forms that can then be absorbed into the bloodstream. When there is not enough lactase to digest the amount of lactose consumed, the results, although not usually dangerous, may be very distressing. While not all persons deficient in lactase have symptoms, those who do are considered to be lactose intolerant.
The Digestive symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose. The severity of symptoms varies depending on the amount of lactose each individual can tolerate. Some causes of lactose intolerance are well known. For instance, certain digestive diseases and injuries to the small intestine can reduce the amount of enzymes produced. In rare cases, children are born without the ability to produce lactase. For most people, though, lactase deficiency is a condition that develops naturally over time. After about the age of 2 years, the body begins to produce less lactase. However, many people may not experience symptoms until they are much older.
Between 30 and 50 million Americans are lactose intolerant. Certain ethnic and racial populations are more widely affected than others. As many as 75 percent of all African-Americans and Native Americans and 90 percent of Asian-Americans are lactose intolerant. The condition is least common among persons of northern European descent.
How is Lactose Intolerance Diagnosed?
The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance test, the hydrogen breath test, and the stool acidity test. These tests are performed on an outpatient basis at a hospital, clinic, or doctor's office. The lactose tolerance test begins with the individual fasting (not eating) before the test and then drinking a liquid that contains lactose. Several blood samples are taken over a 2-hour period to measure the person's blood glucose (blood sugar) level, which indicates how well the body is able to digest lactose.
Normally, when lactose reaches the digestive system, the lactase enzyme breaks down lactase into glucose and galactose. The liver then changes the galactose into glucose, which enters the bloodstream and raises the person's blood glucose level. If lactose is incompletely broken down the blood glucose level does not rise, and a diagnosis of lactose intolerance is confirmed.
The hydrogen breath test measures the amount of hydrogen in the breath. Normally, very little hydrogen is detectable in the breath. However, undigested lactose in the colon is fermented by bacteria, and various gases, including hydrogen, are produced. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In the test, the patient drinks a lactose-loaded beverage, and the breath is analyzed at regular intervals. Raised levels of hydrogen in the breath indicate improper digestion of lactose. Certain foods, medications, and cigarettes can affect the test's accuracy and should be avoided before taking the test. This test is available for children and adults.
The lactose tolerance and hydrogen breath tests are not given to infants and very young children who are suspected of having lactose intolerance. A large lactose load may be dangerous for very young individuals because they are more prone to dehydration that can result from diarrhea caused by the lactose. If a baby or young child is experiencing symptoms of lactose intolerance, many pediatricians simply recommend changing from cow's milk to soy formula and waiting for symptoms to abate.
If necessary, a stool acidity test, which measures the amount of acid in the stool, may be given to infants and young children. Undigested lactose fermented by bacteria in the colon creates lactic acid and other short-chain fatty acids that can be detected in a stool sample. In addition, glucose may be present in the sample as a result of unabsorbed lactose in the colon.
How Is Lactose Intolerance Treated?
Fortunately, lactose intolerance is relatively easy to treat. No treatment exists to improve the body's ability to produce lactase, but symptoms can be controlled through diet.
Young children with lactase deficiency should not eat any foods containing lactose. Most older children and adults need not avoid lactose completely, but individuals differ in the amounts of lactose they can handle. For example, one person may suffer symptoms after drinking a small glass of milk, while another can drink one glass but not two. Others may be able to manage ice cream and aged cheeses, such as cheddar and Swiss but not other dairy products. Dietary control of lactose intolerance depends on each person's learning through trial and error how much lactose he or she can handle.
For those who react to very small amounts of lactose or have trouble limiting their intake of foods that contain lactose, lactase enzymes are available without a prescription. One form is a liquid for use with milk. A few drops are added to a quart of milk, and after 24 hours in the refrigerator, the lactose content is reduced by 70 percent. The process works faster if the milk is heated first, and adding a double amount of lactase liquid produces milk that is 90 percent lactose free. A more recent development is a chewable lactase enzyme tablet that helps people digest solid foods that contain lactose. Three to six tablets are taken just before a meal or snack.
Lactose-reduced milk and other products are available at many supermarkets. The milk contains all of the nutrients found in regular milk and remains fresh for about the same length of time or longer if it is super-pasteurized.
How Is Nutrition Balanced?
Milk and other dairy products are a major source of nutrients in the American diet. The most important of these nutrients is calcium. Calcium is essential for the growth and repair of bones throughout life. In the middle and later years, a shortage of calcium may lead to thin, fragile bones that break easily (a condition called osteoporosis). A concern, then, for both children and adults with lactose intolerance, is getting enough calcium in a diet that includes little or no milk.
In 1997, the Institute of Medicine released a report recommending new requirements for daily calcium intake. How much calcium a person needs to maintain good health varies by age group. Recommendations from the report are as follows:
|Age Group||Amount of calcium to consume daily in milligrams (mg)|
|0-6 months||210 mg|
|6-12 months||270 mg|
|1-3 years||500 mg|
|4-8 years||800 mg|
|9-18 years||1300 mg|
|19-50 years||1000 mg|
|51-70 years||1200 mg|
Also, pregnant and nursing women under 19 need 1,300 mg daily, while pregnant and nursing women over 19 need 1,000 mg.
In planning meals, making sure that each day's diet includes enough calcium is important, even if the diet does not contain dairy products. Many nondairy foods are high in calcium. Green vegetables, such as broccoli and kale, and fish with soft, edible bones, such as salmon and sardines, are excellent sources of calcium. To help in planning a high-calcium and low-lactose diet, figure 2 lists some common foods that are good sources of dietary calcium and shows about how much lactose the foods contain.
Recent research shows that yogurt with active cultures may be a good source of calcium for many people with lactose intolerance, even though it is fairly high in lactose. Evidence shows that the bacterial cultures used in making yogurt produce some of the lactase enzyme required for proper digestion.
Figure 2. Calcium and Lactose in Common Foods
|Foods||Calcium Content||Lactose Content|
|Broccoli (cooked), 1 cup||94-177 mg||0|
|Chinese cabbage (bok choy, cooked), 1 cup||158 mg||0|
|Collared greens (cooked), 1 cup||148-357 mg||0|
|Kale (cooked), 1 cup||94-179 mg||0|
|Turnip greens (cooked), 1 cup||194-249 mg||0|
|Ice cream/ice milk, 8 oz.||176 mg||6-7 g|
|Milk (whole, low-fat, skim, buttermilk), 8 oz.||291-316 mg||12-13 g|
|Processed cheese, 1 oz.||159-219 mg||2-3 g|
|Sour cream, 4 oz.||134 mg||4-5 g|
|Yogurt (plain), 8 oz.||274-415 mg||12-13 g|
|Oysters (raw), 1 cup||226 mg||0|
|Salmon with bones (canned), 3 oz.||167 mg||0|
|Sardines, 3 oz.||371 mg||0|
|Shrimp (canned), 3 oz.||98 mg||0|
|Molasses, 2 tbsp||274 mg||0|
|Tofu (processed with calcium salts)||225 mg||0|
|**Chart information derived from Lactose Intolerance: A Resource Including Recipes, American Diabetic Association, 1991|
Clearly, many foods can provide the calcium and other nutrients the body needs, even when intake of milk and dairy products is limited. However, factors other than calcium and lactose content should be kept in mind when planning a diet. Some vegetables that are high in calcium (Swiss chard, spinach, and rhubarb, for instance) are not listed in figure 2 because the body cannot use their calcium content. They contain substances called oxalates, which stop calcium absorption. Calcium is absorbed and used only when there is enough vitamin D in the body. A balanced diet should provide an adequate supply of vitamin D. Sources of vitamin D include eggs and liver. However, sunlight helps the body naturally absorb or synthesize vitamin D, and with enough exposure to the sun, food sources may not be necessary.
Some people with lactose intolerance may think they are not getting enough calcium and vitamin D in their diet. Consultation with a doctor or dietitian may be helpful in deciding whether any dietary supplements are needed. Taking vitamins or minerals of the wrong kind or in the wrong amounts can be harmful. A dietitian can help in planning meals that will provide the most nutrients with the least chance of causing discomfort
What Is Hidden Lactose?
Although milk and foods made from milk are the only natural sources, lactose is often added to prepared foods. People with very low tolerance for lactose should know about the many food products that may contain lactose, even in small amounts. Food products that may contain lactose include:
Some products labeled nondairy, such as powdered coffee creamer and whipped toppings, may also include ingredients that are derived from milk and therefore contain lactose.
Smart shoppers learn to read food labels with care, looking not only for milk and lactose among the contents but also for such words as whey, curds, milk by-products, dry milk solids, and nonfat dry milk powder. If any of these are listed on a label, the item contains lactose.
In addition, lactose is used as the base for more than 20 percent of prescription drugs and about 6 percent of over-the-counter medicines. Many types of birth control pills, for example, contain lactose, as do some tablets for stomach acid and gas. However, these products typically affect only people with severe lactose intolerance.
Even though lactose intolerance is widespread, it need not pose a serious threat to good health. People who have trouble digesting lactose can learn which dairy products and other foods they can eat without discomfort and which ones they should avoid. Many will be able to enjoy milk, ice cream, and other such products if they take them in small amounts or eat other food at the same time. Others can use lactase liquid or tablets to help digest the lactose. Even older women at risk for osteoporosis and growing children who must avoid milk and foods made with milk can meet most of their special dietary needs by eating greens, fish, and other calcium-rich foods that are free of lactose. A carefully chosen diet (with calcium supplements if the doctor or dietitian recommends them) is the key to reducing symptoms and protecting future health.
Source: based on the Allergy Asthma Information Association's pamphlet "Milk Allergy: The Facts" and the National Institutes of Health document "What is Lactose Intolerance"