Your Symptoms Aren't Always Coming from Lactose

One point made frequently in the NIH state-of-the-science conference on Lactose Intolerance (LI) was that people often misinterpreted the symptoms they got from food. Having symptoms, even when having dairy products, didn't necessarily mean that lactose was the cause.

Another larger and better test of this notion just appeared in the medical journal Clinical Gastroenterology and Hepatology. "Subjective Perception of Lactose Intolerance Does Not Always Indicate Lactose Malabsorption," by Francesc Casellas et al., Volume 8, Issue 7 , Pages 581-586, July 2010.

Abstract.

Background & Aims
Symptomatic lactose intolerance is common; however, abdominal symptoms that patients experience after ingestion of lactose-containing foods can have causes beyond lactose malabsorption. We aimed to determine whether symptoms that patients usually attribute to lactose intolerance are comparable to symptoms provoked by a controlled lactose challenge and whether these symptoms are related to lactose absorption capacity.

Methods
We performed an observational, prospective, transverse study of 353 patients referred for a lactose hydrogen breath test (HBT). Patients completed a validated questionnaire about symptoms associated with consumption of dairy products at home (home symptoms). After a 50-g lactose breath test, they completed the same questionnaire again (lactose challenge symptoms). Patients were assigned to groups of absorbers or malabsorbers according to HBT results and tolerants or intolerants according to the results of the questionnaire.

Results
The total symptom score was significantly higher for home symptoms than for the lactose challenge (16 vs 8, P < .01). Symptoms perceived at home were reported to be more intense than those that followed the lactose challenge for lactose absorbers compared with malabsorbers (16 vs 4, P < .01) and lactose tolerants compared with intolerants (12 vs 2, P < .05). Overperception of lactose intolerance at home was similar in men and women.

Conclusions
Daily life symptoms that patients associate with lactose intolerance are often unrelated to lactose malabsorption. Even among true lactose malabsorbers, symptom recall tends to be amplified by the patient. Thus, conventional anamnesis is a highly unreliable tool to establish symptomatic lactose malabsorption.

A 50 gram lactose challenge is enormous. That's the amount of lactose in four 8-ounce glasses of milk, more than almost anybody normally gets from food. So much lactose should create enormous and violent symptoms in anyone who is truly LI.

Yet the symptoms reported at home from normal food intake were more numerous and more severe than the symptoms reported from the lactose challenge. That's impossible to explain except subjectively. People either are getting their symptoms at home from foods other than lactose (or non-food reasons entirely) or else they simply report symptoms worse than they really are.

LI is real and people do get symptoms from it. But it's not the fault of the most or the worst symptoms for most people. Hard as that may be to believe, here's another test - and of a large number of patients - that replicates that claim.

Report from the LI Conference, part 19

This presentation and the next one are going to infuriate everyone. They're so connected that I'm going to vary from the way I've been handling these posts and put the two of them together.

Dosing, Symptoms, and Tolerable Doses of Lactose
Dennis A. Savaiano, Ph.D.
Professor and Dean
College of Consumer and Family Sciences
Department of Foods and Nutrition
Purdue University

Evidence-based Practice Center Presentation III: The Tolerable Amount of Lactose Intake in Subjects With Lactose Intolerance
Michael Levitt, M.D.
Professor
Minneapolis Veterans Affairs Medical Center
Division of Gastroenterology
Department of Medicine
University of Minnesota

The titles sound innocuous enough. If you click over and read the summaries of the presentations, you'll see that in broad generalities they say very little that I haven't said before and haven't repeated what feels like a dozen times just in my reports on the NIH Conference.

Believe me, the talks that they gave weren't so bland. I'll put it into a sentence.

Nobody gets symptoms from lactose.

Ridiculous, right? Ludicrous even. This whole blog is about lactose intolerance. My books are about LI. The conference was the state-of-the-science on LI. I've received thousand of letters and emails and posts from people telling me about their LI symptoms. Both presenters are researchers who've spent entire careers writing about LI.

Something's totally nuts here. I wish I knew what.

Figures 1 and 2 from Levitt's presentation won't reproduce well here so you have to click over and look at them. They represent the findings from a series of major studies on lactose. A minus sign means that a certain dose of lactose - with other foods in Figure 1, by itself in Figure 2 - produced "no or trivial symptoms" in the test subjects. "Severe symptoms" - the kind I think I get and the kind you tell me you get - are represented by a double plus sign. Remember that an eight-ounce glass of milk has about 12 grams of lactose in it.

When you look at the charts you'll see minus signs for all doses up to and including 12 grams. Virtually no one in the entire set of experiments got symptoms from the lactose in a glass of milk. If you used milk itself or some equivalent, a dose closer to what happens in the real world when you have dairy, no one, not a soul, got symptoms from two full glasses of milk.

Their breath hydrogen goes up, the certain signal that they are lactase maldigesters. But no symptoms.

Savaiano talked about experiments in which subjects received 50 grams of lactose over the course of a day without a single one of them having any symptoms.

Look, as I've reported earlier, the testing in the medical literature is bad. The groups are small, the experiments are not blinded, the doses are not physiologic, meaning that they don't correspond to the foods or eating experiences you get in everyday life. Still. Nothing? No symptoms? Sure, forcing a test subject to drink a full 50 grams of lactose in water - at one time the standard amount of lactose used in testing - will make people sick. But that's like testing for drunkenness by forcing a jug of moonshine down your craw in a single gulp. Anybody would be affected by that. It's so bad a test that doctors stopped recommending its use decades ago.

I didn't get it then, and I don't get it today. I'm reporting what the medical journal evidence says. In the next part I'll give the summary from the draft report. But I'll put the concluding paragraph here.

We stress the importance of additional scientific investigations to provide evidence-based and culturally sensitive recommendations about the amount of daily lactose intake that can be tolerated by lactose-intolerant individuals, with special emphasis on pediatric and adolescent populations and pregnant and lactating women.

That's the biggest "we don't understand what the hell's going on, give us some funding money" you'll ever see in scientific language.

Report from the LI Conference, part 6

The next presentation went to the heart of the whole conference. (Why wasn't it first?)

What Is Lactose Intolerance and How To Measure It
Richard J. Grand, M.D.
Professor of Pediatrics
Harvard Medical School
Program Director
Clinical and Translational Study Unit Director
Center for Inflammatory Bowel Disease
Children's Hospital Boston
[You might remember Children's Hospital Boston from my posts pointing to the research they've done to use injections to reduce milk allergy symptoms.]

What causes the different type, amount, intensity, and duration of lactose intolerance symptoms?

•Quantity of ingested milk
•Fat content of the milk
•Rate of stomach emptying
•Rapidity with which the milk is transported through the intestine
•Individual sensitivity to abdominal discomfort
•Capacity of bacteria in the colon to digest lactose not absorbed in the small intestine
•Psychological impact of anticipation of symptoms in those who have had previous symptoms during milk intake.

Quantity of ingested milk is obvious. The next three are related, and interrelated. As I said on Friday, it's critical to remember that most adults who are lactose malabsorbers still have some residual lactase activity. Anything that slows down the transit time of lactose gives the system more time for the lactose to interact with and be digested by that lactase. Whole bunches of factors regulate how fast food empties from the stomach and goes through the intestines, and one factor that is known to slow transit time is the fat content of the milk.

Items five, six, and seven are also related. The quantity of gases and bloating produced by the bacteria fermenting undigested lactose will depend on what types of bacteria you have and also on how sensitive you might be to intestinal rumblings. Knowing - or thinking that you know - that dairy causes problems might increase your discomfort. And there may be physical differences in your sensitivity to pain. We know for sure that people with Irritable Bowel Syndrome, for example, are far more sensitive to pain and pressure in the colon than people who don't have it. That may also be true for people with LI.

Dr. Grand also explained why an ordinary family physician might not want to send you for formal LI testing. The standard, simple Hydrogen Breath Test costs an average of $773. Somebody has to pay that.

Peppermint Extract for LI? No.

I'm doing mostly questions this week, some new, some old. I like the questions that make me think, and can't just answered by a yes or no, although a yes or no may emerge out of the available evidence. Like this one.

I read something about different things to try for lactose intolerance
including peppermint extract...Are there non-medicinal methods that work?

The basics. Lactose intolerance (LI) is caused by the body not producing enough lactase to digest all the lactose that comes in. That lactose goes to the colon, where it is fermented by bacteria that live in the colon.

That suggests two approaches to alleviating the symptoms: add lactase or get rid of the bacteria.

And those are the two approaches taken. Lactase pills provide the missing lactase. Probiotics, from the cultures in yogurt to targeted pills like Digestive Advantage Lactose Intolerance, DairyCare, or Lactagen, provide the different type of bacteria that digest lactose rather than ferment it.

Neither approach affects the body itself. Lactase is a natural enzyme that works only on lactose. The bacterial supplements thrive in the colon and eat the lactose, but don't themselves enter the body. I'd be hard-pressed to call either one of them medicines. In fact, I'd say that both approaches are non-medicinal to start with.

Being non-medicinal is a big advantage. Neither lactase nor probiotics have side effects. (A tiny, tiny handful of people are allergic to the fungus that lactase is grown from, but even that is not a reaction to the lactase itself.)

Back to peppermint extract. It doesn't do either of the things known to reduce LI symptoms. What does it do? Traditionally, peppermint extract has been used to relieve bloating and gas. LI produces both bloating and gas, because the fermentation of the lactose. There would seem to be a connection.

If so, it's hard to find medical research that backs it up. One interesting report is "Peppermint oil (Mintoil®) in the treatment of irritable bowel syndrome: A prospective double blind placebo-controlled randomized trial," by G. Cappelloa, et al. in the journal Digestive and Liver Disease, Volume 39, Issue 6, June 2007, Pages 530-536. It found that peppermint extract relieved symptoms of Irritable Bowel Syndrome better than a placebo. But patients with LI were excluded from the testing. I can't find any articles that report on testing peppermint extract on patients with LI.

Right now I'd have to say that peppermint extract may help soothe the insides of certain people. Does it help LI? No evidence that it does. Is it non-medicinal? No more than the choices that are known to work. Would I recommend it? No. But reaching that answer proved more complicated than I thought at first.

How Long Does a Lactose Attack Last?

I hate getting questions that I can't answer, but "it depends" is all-too-often the only real comment that I can make.

This was in an email I recently received:

After reading pretty much everything on your website and a lot of others, I still haven't found the answer to this question: How long after you stop consuming lactose does it clear your system and stop causing symptoms? Are there any residual effects and/or damage to the gut?

There is very little that's more individual than a lactose attack. It varies not just by person to person, but every single time you take in more lactose than you can digest. How much lactose you eat, whether it's part of a meal or whether it's mostly liquid, how much lactase may remain in your system, and how sensitive your intestines are all play a major role.

The symptoms may be mild or severe and may last for a short time or for quite a while.

You cannot damage the gut by having lactose. If you are particularly sensitive or also have Irritable Bowel Syndrome, your intestines may keep on spasming even after the lactose is gone. At that point taking an antidiarrheal drug to stop the spasming is a good idea. Don't take one right away thinking that you're stopping the symptoms. You'd just be keeping the lactose in you longer.

Extreme cases of lactose intolerance (LI), meaning times when someone keeps having milk despite the symptoms, can lead to dehydration from the water loss. That used to happen in the days before people knew what LI was. (If you didn't know that milk caused your problem you wouldn't think to stop having it.) I haven't heard of a case of dehydration in a very long time. Knowing all about LI is far too common in the U.S. This might be a concern in some other countries where understanding of LI is just beginning to reach our levels.

LI is uncomfortable but not dangerous. The sympotms will go away when the lactose is gone (and you make sure not take in more lactose). It just seems like forever.