Lactose Intolerance and/or Irritable Bowel Syndrome (IBS)?

September 26, 2012

Recently, the following paraphrased exchange between two participants was posted on another public IBS forum: “Does lactose intolerance cause IBS?” with the response, “Yes, it did for me.”

As useful as “been there, done that” experience from peers with IBS can be in certain contexts, this is a clear example of basic scientific misunderstanding by both individuals involved, and points out the risks of relying too heavily on random, unsourced information found online.

Lactose intolerance and irritable bowel syndrome can both cause abdominal pain or discomfort, diarrhea, bloating and/or excessive gas that may have a strong odor. The severity and symptom pattern may vary among different individuals and may appear to fluctuate, possibly requiring some trial and error with eating habits. Some people who actually have IBS may mistake it for lactose intolerance. Others who actually have lactose intolerance may mistake it for IBS. Both conditions are very common. A publication for health providers from the U.S. National Institute of Child Health and Human Development (NICHD) estimates the prevalence of lactose intolerance in the U.S. alone as 30-50 million adults, which is similar to widely quoted ranges for the number of American adults and children with IBS. Thus, logically, many people with IBS also have or may develop lactose intolerance later, but that’s where the similarity ends. The two conditions involve different parts of the digestive system and have different causes and interventions that help them.

Lactose intolerance is the reduced ability or, much more rarely, the complete inability, to digest lactose, the type of sugar found naturally in any animal or human milk, as well as dairy products and foods with dairy ingredients. Lactose is also sometimes added as a filler to certain medications and other products. The intolerance results from absent or reduced levels of lactase, the enzyme that breaks down lactose. Lactase is produced or not in the small intestine, while IBS affects the function of the colon, also known as the large intestine.

While complex genetic influences in IBS are still being researched, scientists have established that for the vast majority of people with lactose intolerance, it is an autosomal recessive trait, with one copy of the gene in question inherited from each biological parent. In a small subset of this group, often found in Finland, children are born with the inability to produce lactase enzyme at all. This is a serious risk for malnutrition if not diagnosed relatively quickly, as they cannot digest either human breast milk or formulas containing lactose. More commonly, a person gradually loses the ability to process lactose over time, as lactase enzyme production decreases beginning in early childhood and adolescence, though many people will not notice actual symptoms until well into adulthood or even the senior years. This type can be inconvenient but is more easily accommodated than congenital intolerance in babies. While the corresponding gene for lifelong lactose tolerance is dominant, meaning that if  a person inherits one gene for tolerance, and one for intolerance, he or she will be able to tolerate lactose, this gradual (“primary”) lactose intolerance is actually very common in most ethnic groups, including people with genetic origins in the Mediterranean, Asia, Africa, and Ashkenazi Jewish, Hispanic and Native American communities. The prevalence is lowest in those of northern and western European ancestry, with percentages in the single digits, while in most of the other mentioned groups, statistically, a majority of adults will eventually experience some degree of lactose intolerance as part of the natural aging process that can’t be reversed. The overall global prevalence is estimated to be about two-thirds of adults worldwide

In contrast, some people develop what is called secondary lactose intolerance, which may be the result of delayed lactase enzyme production in premature infants, celiac disease, Crohn’s disease affecting the small intestine, chemotherapy, radiation, or other gastrointestinal illnesses or medical procedures that damage the small intestine. If the underlying problem can be dealt with and improved, sometimes this type of lactose intolerance is temporary, but again, these causes have no relationship to the onset of IBS.

Lactose intolerance is rarely an all-or-nothing intolerance. Many people with lactose intolerance can comfortably eat or drink small amounts of dairy products, larger amounts spread out over a longer period of time, or types of dairy products that have relatively lower levels of lactose such as cheese or yogurt.The ability of the digestive system to handle lactose at any given time also depends on what else is being eaten at the same time, which may affect the speed at which lactose or lactase enzyme supplements move through the small intestine and may account for sometimes variable symptoms in the same person.

Unlike with IBS, there are blood, breath or stool tests that physicians can do for lactose intolerance. According to Genetics Home Reference from the National Library of Medicine, also a unit of the National Institutes of Health, genetic tests are also available in several countries in Europe. However, many doctors don’t find any formal tests necessary if a patient’s history or a food diary clearly indicates that avoiding lactose or using lactase enzyme supplements or special reduced or lactose-free food products help consistently. If lactose intolerance is the only gastrointestinal issue, these relatively simple interventions should greatly reduce or eliminate symptoms, but they won’t have any effect on someone who only has IBS. While many people with IBS do report dairy products as a trigger for symptoms, perhaps because of the relatively high fat content, avoiding dairy usually won’t resolve symptoms as readily and consistently as it does with lactose intolerance. For those who have both lactose intolerance and IBS, separating out the influence of each may be more complicated, but it’s undisputed scientific fact that one condition does not cause the other.

For more detailed sources on lactose intolerance, please see the additional reputable links below.

“Lactose Intolerance”, a brief page from IFFGD’s About Kids GI website.

Lactose Intolerance,” a brief page from the U.S. National Digestive Diseases Information Clearinghouse

“Lactose Intolerance” from, a detailed discussion in several online sections.

IFFGD Fact Sheet #122 “Lactose Intolerance: Definition, Symptoms and Treatment”, a free, somewhat more technical article, in downloadable PDF format by Eli D. Ehrenpreis, MD of the University of Chicago and Benjamin Z. Ehrenpreis of Bradley University in Peoria, Illinois.

IFFGD Publication #218, “Why Does Milk Bother Me?” a free article on management of lactose intolerance in downloadable PDF format, adapted from the National Digestive Diseases Information Clearinghouse.

IBS Impact and this blog focus on accurate awareness and advocacy so that people with IBS can make informed decisions. For specific treatment advice  or concerns,  please consult your own health care providers.

National Institutes of Health Research Budget Faces Threatened Cuts for Fiscal Year 2013

September 18, 2012

The International Foundation for Functional Gastrointestinal Disorders and its grassroots arm, the Digestive Health Alliance, have recently renewed their call to advocacy regarding the upcoming U.S. National Institutes of Health fiscal year 2013 budget, that this blog originally discussed on April 18, 2012. In IFFGD’s words, “The NIH is the largest source of funding for medical research in the world. NIH support goes to scientists in universities and research institutions in every state and around the globe.”

In order to meet the requirements of the Budget Control Act of 2011, which was enacted to reduce the federal deficit, NIH faces an automatic 7.8% or $2.5 billion decrease in its budget unless an alternative plan is soon enacted into law.

According to IFFGD’s alert, NIH Director Francis S. Collins, MD, PhD, has stated that such a cut would translate to 2300 fewer grants awarded for the coming fiscal year. For the past several years, because of inflation and zero growth or low growth in NIH budgets, even currently, only 1 out of 7 grant applications to the NIH is successfully funded. IFFGD reports, “This is the lowest ratio in NIH history.”

The current 2012 NIH budget is $30.7 billion.  Many health-related entities,  including IFFGD/DHA, support an increase to at least $32 billion for NIH in fiscal year 2013, rather than the planned decrease.

IFFGD/DHA reports recently that over 150 federal legislators have joined in a request  that NIH be appropriated at least $32 billion for fiscal 2013. As quoted by IFFGD, these Members of Congress “feel this level is absolutely vital in order for NIH to continue improving health through medical science breakthroughs and to maintain international leadership in science and biomedical research.” But more support is needed. IFFGD is asking U.S. citizens to contact their federal Representatives and Senators on this issue and has posted an NIH fiscal 2013 Capwiz alert on its website in the Legislative Action Center section. IBS Impact encourages its members and readers to participate in this advocacy effort

Capwiz is a software program in which you may type your zipcode to look up and easily contact your federal legislators. If you live in a zipcode that falls in more than one district, you will be prompted for the exact street address. Part of the text of an email is automatically provided by IFFGD. All you need to do is add a brief paragraph or two with your personal comments.  Please use your real name and contact information. As many legislators only accept communications from their own constituents, it is important for Congressional staff members receiving your message to know that you are a resident and potential voter in that district and a real person with real needs. They also may wish to reply to you, although it is unpredictable when or if you will receive a response. The Capwiz program is reputable software used for legislative advocacy by numerous organizations and groups. It and IFFGD will protect your privacy and you do not need to be an IFFGD member to use the site. However, if, for any reason, you do not wish to use Capwiz itself, you can contact your legislators directly by email through their official websites, phone, postal mail or fax by using the contact information provided by Capwiz.

IBS Impact members and readers who are not U.S. citizens, although you cannot participate directly in advocating for this issue, increases in the NIH budget will also affect you indirectly. As IFFGD notes in the quoted portion of the first paragraph of this post,  National Institutes of Health grants fund researchers all over the world. Also, in the research community, there is often multinational collaboration, and scientists from outside the U.S. often train or work in the U.S. for a period of time and bring new insights back to their own countries. Different entities within NIH also support and host multinational resources such as the clinical trial database and medical journal databases Medline Plus and PubMed that make a wealth of medical research information available to professionals and the public worldwide. Support for progress in U.S. legislation, funding and research will have ripple effects abroad, just as U.S. citizens with IBS benefit from the work of scientists in many other countries. If you have U.S. citizen friends or relatives who have been supportive about your IBS  and/or who may have another personal interest in functional GI disorders, please consider asking them to support this advocacy effort as well. IBS Impact encourages people with IBS in many countries to alert us to concerns, resources and possible advocacy opportunities in those nations so that we can support and encourage advocacy and awareness efforts worldwide

UNC Online Chat: “Diet for IBS” on September 18, 2012

September 10, 2012

The University of North Carolina Center for Functional Gastrointestinal and Motility Disorders has announced the next online chat in its “Evening with the Experts” series. It will take place Tuesday, September 18, 2012 from 8:00-10:00 p.m. Eastern time.  Erin Slater, RD, LDN, registered dietician at Centennial Medical Group, will present on the topic of  “Diet for IBS.”

People with IBS, and/or their concerned family members and friends are encouraged to make time to attend and participate in this and other UNC chats, which are an excellent, unique opportunity to interact directly with leading researchers and other professionals in the field,  and ask questions and give them feedback about our needs and concerns.

To participate in this or any UNC chat, go to the Center home page about 10 minutes before the starting time, click on the chat icon and follow the instructions given there. Many past video presentations are archived on the Center website, but the actual chat sessions are conducted live and are not archived.

Those who are unfamiliar with UNC’s online chat series may also find this previous post by IBS Impact on July 29, 2011 to be of interest.

U.S. Food and Drug Administration Approves Linaclotide (Linzess) for IBS with Constipation

September 1, 2012

UPDATE:  June 9, 2013– As of mid-May 2013, Constella is available to be prescribed in the United Kingdom. See the May 22, 2013 article by Pharma Times Online Thank you to Dr. Barbara Bradley Bolen, IBS Guide for alerting us to this news.

UPDATE: On December 17, IFFGD posted that linaclotide (Linzess) is now available for prescription in U.S. pharmacies.

UPDATE: On November 28, 2012, Ironwood Pharmaceuticals and Almirall S.A. reported that linaclodtide has been approved for marketing in Europe. It will be known in that region as Constella. Projected availability is the first half of 2013. See the November 30, 2012  post.

UPDATE: On September 21, 2012, IFFGD posted that Ironwood Pharmaceuticals and Almirall, S.A., the company licensed to market linaclotide in Europe, report that the European Committee for Medicinal Products for Human Use (CHMP) has issued a recommendation that linaclotide be approved for prescription to adults with moderate to severe irritable bowel syndrome with constipation (IBS-C). This medication, to be known in Europe by the brand name Constella, still awaits approval by the European Commission, but this recommendation represents progress in the final stages toward linaclotide’s approval and availability in Europe. No projected date is known at this time. Here is IFFGD’s original announcement on Constella.

Earlier this week, the U.S. Food and Drug Administration approved the use of linaclotide for use in treating chronic idiopathic constipation or irritable bowel syndrome with constipation in adults, 18 and older, both men and women. The new medication, which is an oral capsule to be taken once a day, is to be marketed jointly by Ironwood Pharmaceuticals and Forest Laboratories and will be known in the U.S. as Linzess. Linzess has not received FDA approval for use in children ages 17 or younger.

According to IBS Guide Barbara Bradley Bolen’s recent blog post on linaclotide, the medication is still undergoing the approval process in Europe, where the brand name is Constella. In addition, material directly from Ironwood Pharmaceuticals indicates that Ironwood has licensed linaclotide to another pharmaceutical company for potential use in several countries in Asia, but no information has been given at this time as to the current status of clinical trials or approval in that region of the world.  Both of the above linked sources  include a brief explanation of what the medication is and how it is believed to work. The original FDA press release on Linzess is linked here. The New York Times, via Reuters, reports that Linzess is expected to be available for physicians to prescribe “in the fourth quarter,”  apparently meaning by the last few months of this year.

As many in the IBS community are aware, FDA-approved prescription medications specifically for irritable bowel syndrome of any subtype are extremely limited, and no single treatment, whether it is medication, diet, psychological interventions, or others, proves appropriate or effective for every individual with IBS, even those with similar symptom patterns. It has been several years since a new prescription IBS drug was last made available.  IBS Impact is pleased that those with constipation-predominant IBS will soon have another option, and urges those who are considering  Linzess to read the available information, to familiarize themselves with the benefits and risks and to consult their own doctors as to if Linzess is worth trying in  their specific situations. IBS Impact focuses on awareness and advocacy and does not endorse particular treatments, but does encourage accurate and up to date information from reputable sources so that individuals with IBS and their families can make the most informed choices for their own needs and desires.