FODMAPs and Gastroenterology (Part 3)

FODMAPs and Gastroenterology

—or—

Why does this diet actually help?

This three-part blog series is based largely on an article published in December 2012 in Practical Gastroenterology, “A FODMAP Diet Update: Craze or Credible?” Series editor: Carol Rees Parrish, M.S., R.D. Article authors: J. Reggie Thomas, DO, Banner Good Samaritan Medical Center. Rakesh Nanda, MD, FACP, FACG, Phoenix VA Health Care System. Lin H. Shu, MS, RD, Phoenix VA Health Care System, Phoenix, AZ.

That journal is published for people who read at the MD or PhD level. This blog series is an attempt-to-translate for the rest of us!


Part Three: Testing the Low-FODMAP Diet

After reading the last two blog posts on CCF, you now know more than you really wanted to know about the different kinds of sugars that are in your foods. What about the medical evidence behind the low-FODMAP diet?

Early IBS researchers focused mostly on fructose and lactose, and they helped many IBS sufferers. Then in 2006, Dr. Shepherd’s ground-breaking study showed that restricting ALL FODMAPs “led to sustained improvement in all gut symptoms in 77% of 62 patients with IBS and fructose malabsorption.” That is an enormous percentage! In 2008, further study was conducted (the researchers call it “double-blinded, randomized, quadruple arm, placebo-controlled rechallenge trials,” if that impresses you! It impressed my gastroenterologist).

The double-blinded etc. study was even MORE encouraging. 77% of patients who consumed the FODMAPs fructose and fructans, and 79% who consumed a mixture of fructose, fructans, and glucose, “reported their symptoms were not adequately controlled” … but only 14% of people who consumed glucose only! Glucose, a non-FODMAP sugar, did not seem to be causing IBS symptoms in most people.

The picture just kept getting clearer.

[Please note: We are not talking about people whose diagnoses included celiac, Crohns, or other severe intestinal issues—that’s why it is vital to go to your doctor FIRST and make sure you aren’t suffering from one of those very different illnesses. IBS has traditionally been a “diagnosis of exclusion,” meaning they couldn’t find anything else wrong with us.]

A 2010 study confirmed that FODMAPs sometimes create discomfort by increasing gas production—like blowing up your insides as a balloon. And a 2011 study of 82 patients showed statistically significant results for limiting FODMAPs. In that study, it decreased “bloating, abdominal pain, and flatulence.”

So the authors of this medical-journal article ask, “How should the FODMAP diet be used?” and they answer, “with a dietician’s assistance.” They suggest getting a referral from your physician, and then hopefully getting 1) hydrogen breath testing, which can show exactly which sugars you aren’t tolerating, 2) dietitian referral (Yes, the article spells “dietician/dietitian” both ways—who but a compulsive copy editor is likely to notice?), 3) complete FODMAP restriction for 6 weeks—cutting ALL of them out of your diet, to give your symptoms a chance to go away, and then 4) a “slow controlled reintroduction of FODMAPs to determine the level that will be tolerated.”

I like #4. It gives me hope. It means that I might not have to go without all these sugars for the rest of my life. But even if I do, I believe it’s worth it to feel this much better. I don’t know how I stopped making some of those transporter molecules (Part One), if that’s what happened. I do know I used to be able to eat all those foods, though I always had some gas/bloating issues. But things got much worse after a stressful time in my life. Maybe you had a similar experience.

Summing up, the authors of this respected-scientific-journal article write, “The FODMAP diet may once have been a craze, but now with an increasing body of evidence behind it, is definitely a credible and valuable tool in the management of patients with FGID.”

Print that paragraph—and the title & date of this journal article—take it all to your doctor, and get started!

 

FODMAPs and Gastroenterology (Part 2)

FODMAPs and Gastroenterology

—or—

Why does this diet actually help?

This three-part blog series is based largely on an article published in December 2012 in Practical Gastroenterology, “A FODMAP Diet Update: Craze or Credible?” Series editor: Carol Rees Parrish, M.S., R.D. Article authors: J. Reggie Thomas, DO, Banner Good Samaritan Medical Center. Rakesh Nanda, MD, FACP, FACG, Phoenix VA Health Care System. Lin H. Shu, MS, RD, Phoenix VA Health Care System, Phoenix, AZ.

That journal is published for people who read at the MD or PhD level. This blog series is an attempt-to-translate for the rest of us!


Part Two: More About FODMAP Sugars

The previous post concluded that it’s vital to make sure most of the sugars we eat will be absorbed in the SMALL intestine.

This post will provide more information about all those different sugars: Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols…a.k.a. FODMAPs.

First, the fermentable oligosaccharides: these are molecules made up of chained-together sugars. Fructans is an important one for us, because it’s a chain of fructose (remember fructose!) molecules with a glucose molecule on the end. And here’s the problem, quoting the article: “fructans are not transported across the epithelium [intestinal lining] or absorbed at all. Studies have shown that 50-90% of ingested fructans can be recovered from stool output of patients with an ileostomy.” In other words, this molecule is NOT well absorbed in the small intestine, so it can be a major troublemaker farther down the line.

The biggest source of fructans in the North American diet is … brace yourself … WHEAT. I suspect that a high percentage of people who feel better when they give up wheat (including people who test negative for celiac disease) are not bothered by gluten at all, but by fructans! That’s why a tiny piece of bread (e.g. taking Communion) might be tolerated, instead of creating a full-blown allergic reaction…and this could be one reason some people feel better on a gluten-free diet.

The other oligosaccharide (chained-together sugar) that’s important to FODMAPers is galactans. They’re chains of the sugar galactose, with a fructose molecule on the end, and they behave just like fructans. Foods such as beans and brassicas (cabbage and its kin) are high in galactans. Even the general population notoriously has problems with galactans. Remember the song, “Beans, beans, the musical fruit…”?

The second major group of sugars that’s discussed in the article is “disaccharides and monosaccharides,” the DM part of the FODMAP acronym, and this is where fructose (remember fructose!) comes in. Two fructose molecules linked together is called “sucrose” (we know sucrose as common table sugar), but when the body breaks it down, one of them becomes glucose. Interestingly, the fructose and glucose can be absorbed together into the bloodstream by one of the “transporters” I mentioned in the previous post.

If you’re starting to feel overloaded by all this chemistry, don’t worry. Here’s the essence, quoting once more: “Therefore malabsorption of fructose occurs when fructose is present in excess of glucose. Some foods rich in fructose are honey, prunes, dates, apples, pears, and papaya.… It is also often added to commercial foods and drinks as high fructose corn syrup.” Ah, HFCS. Our least favorite food, and among the hardest to avoid.

And then there’s lactose. It can also cause FODMAP-related symptoms. Lactose is in most dairy products. The article also says it can be found in beer (who knew?) and prepared soups/sauces (READ YOUR LABELS).

Third group: polyols (and there’s the final “P” in FODMAP). They’re present in most artificial sweeteners. Eating them together with glucose does not help their absorption. Instead, “A few studies have found that sorbitol and fructose ingested together cause worsening IBS symptoms” (my emphasis)

Besides diet soda and other artificially sweetened foods, watch out for polyols in toothpastes, mints, sugar-free chewing gum, and liquid cough/cold or pain relief medicines. If an artificial-sounding ingredient ends with –ol, it’s probably a polyol: mannitol, xylitol, and sorbitol are among the commonest.

Ugh. That’s a lot to digest (ha ha) in one blog post. A hopeful note: Trying the low-FODMAP diet does not necessarily mean giving up ALL these sugar molecules for the rest of your life! That will be discussed in Part Three of this blog series.

FODMAPs and Gastroenterology (Part 1)

FODMAPs and Gastroenterology

—or—

Why does this diet actually help?

This three-part blog series is based largely on an article published in December 2012 in Practical Gastroenterology, “A FODMAP Diet Update: Craze or Credible?” Series editor: Carol Rees Parrish, M.S., R.D. Article authors: J. Reggie Thomas, DO, Banner Good Samaritan Medical Center. Rakesh Nanda, MD, FACP, FACG, Phoenix VA Health Care System. Lin H. Shu, MS, RD, Phoenix VA Health Care System, Phoenix, AZ.

That journal is published for people who read at the MD or PhD level. This blog series is an attempt-to-translate for the rest of us!


Part One : One Cause of Our Symptoms

When doctors don’t see anything structurally wrong with the appearance of our insides, they refer to our problems as “functional” instead of “structural.” One of the commonest “functional” gastrointestinal diagnoses is Irritable Bowel Syndrome or IBS, essentially meaning the doctors haven’t known what’s actually wrong—and it affects about 15% of the world’s population!

Research in the early 2000s suggested that FODMAP sugars make IBS worse in one of three possible ways: 1) food allergies, or hypersensitivity, 2) something those sugars did to the intestines, or 3) what they called “luminal distension,” which translates to “gas stretching the intestines and making them hurt.”

This journal article starts by explaining how carbohydrates—sugars, and food molecules that can be broken into sugars—are absorbed into the body. This is crucial for people with IBS, because it’s the sugars that are NOT absorbed (“absorption” happens in the small intestine) that get dumped into the large intestine, creating symptoms for people who are FODMAP-sensitive.

FODMAP sugars will be explained in the next post.

There is some chemistry involved in what happens in the small intestine, because “sugar” comes in several molecular forms. Our bodies have different ways of recognizing and dealing with the different kinds of molecules. In our small intestines, research has found three different “transporter” molecules that help sugars cross through intestinal cells into the bloodstream.

One kind of molecule transports the sugars glucose and galactose. One transports only fructose (remember “fructose”!). The third carries the sugars glucose, fructose, and galactose—but it’s best at carrying fructose if there is glucose or sucrose present in the food it’s trying to digest.

Let me quote the article briefly: “Symptoms of FGID [functional gastrointestinal disorders] can result from the malabsorption of fructose and sucrose that occurs when the activity of one of these transporters is altered… [translation: if something happens to our bodies’ production of one of those “transporter” molecules, we can’t absorb those sugars as well as we used to] … When the small intestine is unable to absorb fructose, it is transported into the large intestine where it is fermented by colonic flora [bacteria].” In other words, the unabsorbed sugars go where they do us no good at all. Even harm! Also  load of indigestible sugars creates an “osmotic effect” that draws water out of the body into the large (lower) intestine. Increased water in the lower intestine causes diarrhea. This is how some laxatives work.

This first section of the article is pretty convincing evidence that it’s vital to make sure that most of the sugars we eat will be absorbed in the small intestine, so they don’t pass downstream to the large intestine and overfeed those colonic bacteria.

Part Two coming soon!