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: diarrhea vomiting abdominal bloating stomach cramps gas
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

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)
casein	lactoferrin	sodium caseinate
caseinate	lactoglobulin	solids
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
flavouring	milk protein

baked goods	deli meats	milk
butter	egg substitutes	pizza
buttermilk	frozen yogurt	pudding
candy	gravy	salad dressing
cheese	ghee	sausages
chocolate	Half & Half	seasoning
cream	hot dogs	sherbert
cream soups	ice cream	sour cream
curds	kefir	yogurt
custard	margarine

Lactose Intolerance

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:

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

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.

Summary

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"