70 million Americans deal with digestive disorders…only one magazine does

Lactose Intolerance:

Symptoms of Lactose Intolerance

Millions of people suffer from lactose intolerance, and many of them are not even aware of it. Learn how to recognize and alleviate the symptoms of this common disorder.

By Christopher D. Daniels

Milk may be the "perfect food" when we enter this world, but by the time we reach two years of age many of us — up to 90 percent in some ethnic groups — begin to lose our ability to digest it. The culprit, a sugar called lactose that is found in dairy products, cannot be absorbed by our body unless it is broken down by an enzyme called lactase in our digestive system. Most people produce less lactase as they age, and this can result in a very uncomfortable, but rarely dangerous, disorder called lactose intolerance.

According to the National Institutes of Health, as many as 50 million Americans suffer from lactose intolerance, which can cause symptoms such as abdominal cramps, painful bloating and gas, and even diarrhea and nausea in some cases. These symptoms usually occur within two hours of consuming a dairy product and range from mild discomfort to severe distress. The level of severity is determined by how much lactose we consume and how much lactase we produce to digest it. If the lactose is not digested, it passes down to the large intestine, or colon, where it is fermented by bacteria, and this causes gas to form. Indigestible sugars in beans produce a similar result — and that is something we can all relate to! "Excessive gas is the primary symptom of lactose intolerance; diarrhea is relatively rare," says Michael D. Levitt, MD, a gastroenterologist at the Veterans Affairs Medical Center Minneapolis. "We just completed a study in which people with lactase deficiency were given a lot of lactose — 35 grams between breakfast and lunch. The participants had a lot of gas but no diarrhea."

For some people, however, the excess lactose and gas interfere with the normal absorption of liquid by the intestinal lining, and this may cause diarrhea. The combination of symptoms can result in "explosive diarrhea," a condition that requires no further explanation. A few bouts of explosive diarrhea is more than enough motivation for most people to start looking for answers to their problem.

We All Suffer from These Symptoms Occasionally, So How Can One Tell If It’s Lactose Intolerance?

A self-diagnosis of lactose intolerance is often a misdiagnosis. Several research studies have documented that people who believe they are lactose intolerant, frequently are not. On the other hand, many people suffer from the disorder and are not aware of it.

Without the help of a physician, lactose intolerance can be a tricky disorder to diagnose for a number of reasons. The symptoms are, in fact, deceptively similar to those that many of us experience anytime we eat something that "doesn’t agree with us." Plus, each person has a different tolerance level for lactose. If your tolerance level is fairly high, or if your diet is low in dairy products, you may only occasionally consume enough lactose to trigger symptoms. When you do experience symptoms, you may attribute them to last night’s spicy Mexican dish or the hot dog you purchased from a street vendor earlier in the day, and — like many people — you may go through your whole life never associating your symptoms with dairy products.

Kirsten Shurb, 22, of Minneapolis, has suffered from lactose intolerance for about six years. "When I first started having symptoms, I wasn’t sure what was causing them," she says. "I kept switching cereals — thinking the cereal might be the problem. Now, I know it was the milk in the cereal that was the problem."

Unfortunately, simply eliminating milk from your diet doesn’t always make diagnosing lactose intolerance any easier. Many sufferers can drink some milk without experiencing symptoms. Self-diagnosis is further complicated by the fact that lactose is also found in other dairy products such as ice cream, yogurt (without live cultures), sour cream and processed cheese. It also can be found in some foods that you might not expect, such as cake, bread and other baked goods, chocolate, salad dressing and some lunch meats. Even products labeled "nondairy," such as powdered coffee creamer and whipped toppings, may contain lactose. When purchasing these products, read the labels carefully. Look for words such as whey, curds, milk by-products, dry milk solids and nonfat dry milk powder. If any of these ingredients are listed on a label, the product contains lactose.

Kirsten knows the importance of reading labels. "I had a veggie burger once because I thought it would be dairy free. Several of my friends are vegans, and everything they eat is free of any animal products so I assumed that a veggie burger would be OK. Unfortunately, I got extremely sick after eating the burger," says Kirsten. "When I dug the box out of the garbage and looked at the label, I discovered that the veggie burger was loaded with cheese."

Lactose also can be found in more than 20 percent of prescription drugs and about 6 percent of over-the-counter (OTC) medicines. Birth control pills, for example, contain lactose (except for G.D. Searle’s Demulen^®, which only has lactose in the 7-day placebo pills), as do some OTC medications for gas and stomach acid such as the chewable tablet form of Pepcid AC^®. So why do drug manufacturers add lactose? Because lactose is virtually tasteless except for a mild sweetness, it makes an ideal filler, and it is used to prevent caking in chewable tablets. It is also used to create the shiny, hard coating that makes some pills easier to swallow. These medications usually contain less than 25 milligrams of lactose (compared to 12,000 milligrams in an eight-ounce glass of milk), which is rarely enough to cause a problem for anyone. However, for an individual with an extremely low tolerance, it can all add up. Plus, all of these hidden sources of lactose can make self-diagnosis even more difficult for people who are unsure if they are intolerant.

Further complicating self-diagnosis is the fact that most people gradually become more lactose intolerant as they age. As an adult, you may only be able to digest one-tenth of the amount of lactose that you could handle as an infant. No one knows what causes this change, but the tendency to be lactose intolerant is inherited. The subtle onset of symptoms as we age can mistakenly be attributed to something new in our diet or to stress. A food that we have enjoyed for most of our lives without problems is rarely suspected.

Despite the challenges, some people, like Pat LaPlante, 34, of Washington, D.C, are able to self-diagnose their lactose intolerance — but only after struggling with the symptoms for months or even years. "When my symptoms first occurred, I was in graduate school and working full-time, so I thought that stress was affecting my stomach," says Pat. "Then, one day, I was talking to my sister on the phone, and I mentioned my symptoms. She said, ‘oh, that sounds like the symptoms I was having when I found out that I was lactose intolerant.’ When she mentioned that, I tried removing all dairy products from my diet, and, sure enough, all of the symptoms went away."

How to Know for Sure

If you are concerned that you may suffer from lactose intolerance, then you should see a physician if you want a quick and accurate diagnosis. Several tests are available that can be performed on an outpatient basis. One test entails measuring your blood-sugar level before and after you drink a liquid containing lactose. If you digest the lactose normally, your blood sugar level should rise. If it doesn’t, then you are lactose intolerant. If your body is not digesting lactose, various gases, including hydrogen, are produced in your large intestine. The hydrogen is absorbed into your bloodstream, carried to your lungs and exhaled. Hence, a breath test to measure increased levels of hydrogen is also commonly used to diagnose lactose intolerance. Yet another test measures the level of lactic acid in stool. Undigested lactose increases the amount of lactic acid and other substances in the stool.

These tests are fine for adults, but typically are not used for a diagnosis in babies since they are rarely lactose intolerant. However, babies frequently experience symptoms similar to those of lactose intolerance, and when this occurs, most pediatricians simply recommend switching the baby from cow’s milk to soy formula. Annette Daniels of Winchester, Va., did just that after her 6-month-old daughter, Brooke, kept waking up during the night screaming from gas pain. "The change was instantaneous," says Annette. "As soon as we switched her over to the soy formula, her symptoms lessened and she, along with the rest of the family, started sleeping better during the night." Since Brooke was not tested, it is not known if she suffers from lactose intolerance or from a milk allergy, which is usually a reaction to the protein in milk and not related to lactose intolerance. Regardless, switching Brooke to a soy formula eased her discomfort.

I Am Definitely Lactose Intolerant, What Should I Do?

After a diagnosis of lactose intolerance, most sufferers set out to avoid dairy products and lactose completely. As already discussed, this can be more difficult than it appears because lactose can turn up in many unexpected places. Furthermore, milk and other dairy products are major sources of calcium and other important nutrients. A shortage of calcium in our diets can lead to a condition called osteoporosis, which is characterized by thin, fragile bones.

For most sufferers, eliminating some, but not necessarily all, dairy products is an option. Research studies have shown that people with confirmed low levels of lactase can consume one serving of milk with a meal or as many as two servings per day when divided between breakfast and dinner, without experiencing symptoms. Learn your tolerance level by drinking one-fourth cup of milk with a meal and gradually increasing your intake. Exclude all other dairy products from the meal, and keep in mind that low-fat and skim milk contain the same amount of lactose as whole milk.

Another advantage of gradually increasing the amount of lactose in your diet is that your ability to tolerate it may actually improve. "By slowly increasing the amount of lactose you consume, you can presumably promote the increase in your intestinal bacteria of another enzyme, similar to lactase, which breaks down lactose without producing excessive gas," says Robert Russell, MD, a gastroenterologist at Tufts Nutrition Center in Boston and an associate editor of Digestive Health & Nutrition.

Another thing to consider before eliminating dairy foods from your diet is that some products have less lactose than others. Cheese is generally much lower in lactose than milk, and aged cheeses, such as cheddar, gouda and Swiss, have lower levels of lactose (less than 1 gram) than processed cheeses. "Most cheeses are so low in lactose that they do not cause a problem for people with lactase deficiency," says Dr. Levitt.

Other dairy products to consider keeping in your diet include buttermilk and yogurts labeled "live active cultures," which contain the bacterium Lactobacillus acidophilus. It helps break down the lactose in the yogurt while it is still in the container. However, do not rush out to purchase supplements containing this bacterium. A recent study co-authored by Dr. Russell found that the bacteria do not survive long enough in the digestive system to aid in breaking down the lactose when taken with dairy products.

Lactose-free dairy products provide yet another option for enjoying dairy foods even if you are lactose intolerant. Lactose-reduced or lactose-free milk, cheese, ice cream, yogurt and even whipped cream are available.

Over-the-counter drops and tablets containing lactase also are available to assist with the digestion of dairy products without discomfort. Lactase drops are sold under the brand names Lactaid^® and Dairy Ease^®. These drops help break down the lactose when added to milk. More than a dozen companies offer the lactase tablets, which can help alleviate the symptoms of intolerance when taken before consuming dairy products. "If I am going out to a restaurant, I take lactase tablets just to be safe," says Kirsten. "You never know what they are cooking with."

Walter Cornejo, a Washington, D.C., resident was diagnosed with lactose intolerance at 14 years of age. His physician used the stool acidity test to confirm his diagnosis. Walter says that he has tried lactase tablets and has found they do help some, however he still tries to avoid dairy products. "The problem is that I forget to take them, or I don’t have them with me when I need them," he says.

Walter is not alone; many lactose intolerance sufferers opt to forgo dairy products altogether. Many non-dairy, lactose-free substitutes, including milk, creamer and whipped cream, are available if you choose to go this route. Most of these products are soy or rice based and are popular among people who are lactose intolerant as well as vegetarians. Kirsten says that she prefers the taste of rice milk over lactose-free cow’s milk, and she points out that the rice milk is a good source of calcium.

If you do eliminate milk from your diet, make sure that, like Kirsten, you substitute other calcium-rich products. Green vegetables, such as broccoli, kale and collard greens, and fish with soft, edible bones, such as salmon and sardines, are excellent sources of calcium. Calcium-based chewable antacid tablets are another good source of calcium and can be taken safely on a regular basis.

Although Walter has given up dairy products altogether, he is adamant about his love of cheeses. "If I do slip and eat a dairy product, I need to make sure that I am near a restroom," says Walter. "Even a tiny little square of cheese is a problem." According to Dr. Russell, this level of intolerance is not unheard of. "It is true some people tend to be very sensitive because they probably produce no lactase at all," he points out. "However, for most people it’s not all or nothing but rather a gray zone: they have reduced levels of lactase, but it is not totally absent." Walter takes a daily multivitamin supplement with calcium to ensure that he is getting an adequate amount of calcium.

When properly diagnosed, the symptoms of lactose intolerance can be effectively managed. Yet, many people who battle this disorder suffer needlessly on a daily basis. If you suspect that you suffer from lactose intolerance, see a gastroenterologist who can help diagnose your condition and provide guidance on how to end your suffering.

Christopher D. Daniels is on staff at the American Gastroenterological Association as managing editor of Digestive Health & Nutrition. He has devoted his career to improving health-care communications, and he was a driving force behind the inception and launch of Digestive Health & Nutrition.

According to the National Institutes of Health, lactose intolerance affects all ethnic groups, but is more prevalent in some groups than others.

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