Lactose Intolerance

Lactose Intolerance Definition Lactose intolerance, also called lactase deficiency, means you aren't able to fully digest the milk sugar (lactose) in dairy products. It's not usually dangerous, but symptoms of lactose intolerance can be uncomfortable enough to steer you clear of the dairy aisles. The problem behind lactose intolerance is a deficiency of lactase — an enzyme produced by the lining of your small intestine. Some people who think they are lactose intolerant actually don't have impaired lactose digestion. And not everyone with low levels of lactase is lactose intolerant. Only people with low lactase levels and symptoms are considered to have lactose intolerance. You can control symptoms of lactose intolerance through a carefully chosen diet that limits lactose without cutting out calcium, and possibly by taking supplements.

Symptoms The signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include:     

Diarrhea, which is the most common symptom Nausea Abdominal cramps Bloating Gas

Symptoms are usually mild but may sometimes be severe. The severity of symptoms doesn't correlate with the degree of lactose malabsorption. Instead, symptoms relate to a range of factors, including ethnicity, age and how fast you digest food. Lactose intolerance isn't easily diagnosed by signs and symptoms alone. Many other conditions, including stomach flu and irritable bowel syndrome, can give you similar symptoms. In young children, diarrhea along with certain other symptoms may be a sign of milk protein allergy.

Causes Small intestine

The cells that line your small intestine produce an enzyme called lactase. Lactase breaks down lactose into two simple sugars — glucose and galactose — which can be absorbed into your bloodstream. Without lactase, the unprocessed lactose moves on to the colon, where the normal intestinal bacteria contend with it. This causes the hallmarks of lactose intolerance — gas, bloating and diarrhea. There are three types of lactose intolerance. Normal result of aging for some people (primary lactose intolerance) Normally, your body produces large amounts of lactase at birth and during early childhood, when milk is the primary source of nutrition. Usually your lactase production decreases as your diet becomes more varied and less reliant on milk. This gradual decline may cause symptoms of lactose intolerance. Result of illness or injury (secondary lactose intolerance) This form of lactose intolerance occurs when your small intestine decreases lactase production after an illness, surgery or injury to your small intestine. It can occur as a result of intestinal diseases, such as celiac disease, gastroenteritis or an inflammatory bowel disease like Crohn's disease. This type of lactose intolerance may last only a few weeks and be completely reversible. However, if it's caused by a long-term illness, it may be permanent. Condition you're born with (congenital lactose intolerance) It's possible for babies to be born with lactose intolerance. This rare disorder is passed from generation to generation in a pattern of inheritance called autosomal recessive. This means that both the mother and the father must pass on the defective form of the gene for a child to be affected. Infants with congenital lactose intolerance are

intolerant of the lactose in their mothers' breast milk and have diarrhea from birth. These babies require lactose-free infant formulas.

Risk factors A few risk factors can make you or your child more prone to lactose intolerance: 

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Age. Lactose intolerance usually starts after age 5 — the condition is uncommon in babies and young children. A child with chronic diarrhea before age 1 usually has another underlying problem. Ethnicity. Lactose intolerance is more common in certain ethnic and racial populations. Lactose intolerance is more common in black, Asian, Hispanic and American Indian populations. Premature birth. Infants born prematurely (28 to 32 weeks of gestation) may have reduced levels of lactase, because this enzyme increases in the fetus late in the third trimester.

When to seek medical advice If you have signs and symptoms of lactose intolerance, talk to your doctor. Don't diagnose yourself. Your symptoms could be an indication of another illness. Your doctor can help determine if you have lactose intolerance or another condition.

Tests and diagnosis Your doctor may diagnose lactose intolerance based on your symptoms and your response to reducing the amount of dairy foods in your diet. Your doctor can confirm the diagnosis by conducting one or more of the following tests: 

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Lactose tolerance test. You'll need to avoid eating before this test, to ensure accurate results. Once at the doctor's office, you'll drink a liquid that contains high levels of lactose. When this lactose reaches your digestive system, the lactase enzyme normally breaks it down into glucose and galactose, which can be absorbed by your bloodstream. In this test, you'll give blood samples over a two-hour period to measure your glucose level. If your glucose level isn't rising, it means you aren't properly digesting and absorbing the lactose-filled drink. Hydrogen breath test. This test also requires you to drink a liquid that contains high levels of lactose. Then your doctor measures the amount of hydrogen in your breath at regular intervals. Normally, very little hydrogen is detectable. However, undigested lactose reaches your colon and ferments, causing hydrogen and other gases to be released, absorbed by your intestines, and eventually exhaled. Large amounts of exhaled hydrogen indicate that you aren't fully digesting and absorbing lactose and that you're probably intolerant. Stool acidity test. Infants and children suspected of having lactose intolerance take a stool acidity test. The amount of lactose required for the lactose tolerance test or the hydrogen breath test may be dangerous for infants and children. The stool acidity test measures the amount of acid in the stool.

Undigested and unabsorbed lactose ferments in the colon, creating lactic acid and other acids that can be detected in a stool sample.

Lifestyle and home remedies You can't improve your body's ability to produce lactase. But you can usually control the symptoms of lactose intolerance by modifying your diet and using special products made for people with this condition. You may not have to completely avoid dairy foods. Most people with lactose intolerance can enjoy some milk products without symptoms. You may even be able to increase your tolerance to dairy products by gradually introducing them into your diet. Keeping milk products on your menu can be beneficial, because milk products provide essential nutrients, such as calcium, vitamins A and D, riboflavin, and phosphorus. Avoiding milk entirely can make it difficult to get the amount of calcium you need for healthy bones and teeth. Here are some tips for changing your diet to minimize symptoms of lactose intolerance without minimizing your calcium intake: 

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Drink less milk more often. Sip small servings of milk — 2 to 4 ounces (59 to 118 milliliters) at a time. The smaller the serving, the less likely it is to cause gastrointestinal problems. Save milk for mealtimes. Drink milk with other foods, rather than drinking milk alone. This slows the digestive process, so you reduce your chance of experiencing lactose intolerance. Experiment with an assortment of dairy products. Not all dairy products have the same amount of lactose. For example, hard cheeses such as Swiss or cheddar have small amounts of lactose and generally cause no symptoms. You may well be able to tolerate cultured milk products, such as yogurt, because the bacteria used in the culturing process naturally produce the enzyme that breaks down lactose. However, some yogurts have milk added back after fermentation and may cause symptoms. Substitute nondairy coffee creamers or soy or rice milk. Buy lactose-reduced or lactose-free products. You can find these products at most supermarkets next to the regular dairy products. They may be more expensive, but they contain all of the nutrients found in their lactose-loaded counterparts. Watch out for hidden lactose. You may be overloading on lactose without realizing it. Although milk and foods made from milk are the only natural sources of lactose, this sugar is often added to prepared foods, such as cereal, instant soups, salad dressings, milk chocolate and baking mixes. Before putting these items in your grocery cart, check their labels for milk and lactose in the ingredient list. Also look for other words that indicate lactose, such as whey, milk byproducts, fat-free dry milk powder, malted milk, buttermilk and dry milk solids. In addition, you'll need to look for lactose in any prescription and over-the-counter medications you're taking. Many medicines contain lactose, but because they contain only very small amounts, they typically affect only people with severe lactose intolerance.

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Seek other sources of calcium. If you can't tolerate dairy products in large amounts, you can get calcium in broccoli, leafy greens, canned salmon, almonds, oranges, certain kinds of tofu and soy milk, and calcium-fortified breads and juices. Talk to a dietitian if you need ideas for getting more calcium into your diet.

Supplements Supplements also may help you manage lactose intolerance: 

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Use lactase enzyme tablets. These tablets contain the enzyme that breaks down lactose, reducing the amount your body must digest on its own. You can take tablets just before a meal or snack. Improvement of symptoms may vary from one person to another, but tablets do help many people. Take a calcium supplement. Calcium supplements are helpful for many people, but especially if you have lactose intolerance and are unable to eat dairy products. Try probiotics. Probiotics are living organisms present in your intestines that help maintain a healthy digestive system. Probiotics are also available as active or "live" cultures in some yogurts and as supplements in capsule form. These are sometimes used for gastrointestinal conditions such as diarrhea and irritable bowel syndrome. They may also help your body digest lactose. Probiotics are generally considered safe if used properly and may be worth a try if other methods don't help.

If you have lactose intolerance, keep antidiarrheal agents on hand. Antidiarrheal agents such as loperamide (Imodium A-D) help reduce symptoms of lactose intolerance.