IBS--Free at Last!

How do Probiotics Fit In On a FODMAPs Elimination Diet?

You and I both want to know! I don't have all the answers, but I'd like to share some of my thoughts on this, since it is one of the most frequent queries I receive. I look forward to reader and professional comments on this one.

I think we can all agree that bacterial fermention in the gut is normal and desirable to a certain point. The bacteria in our guts have their own jobs to do for us, and they have to eat--fermentation is how they do it. This normal state of affairs can be disrupted by illnesses, infections, use of antibiotics, or food intolerance or allergies. If too much gas is produced as a result of bacterial imbalance, it can be part of the IBS picture

Or, the bacterial fermentation piece might be perfectly normal, but your nervous system may be so sensitive that you experience normal gas expansion of the colon and abdomen as a painful sensation.

When we use a FODMAPs restricted diet we deprive certain gut bacteria of their favorite foods. This decreases gas production. But we don't want to give up the health benefits of the short chain fatty acids (SCFAs) and other substances that gut bacteria produce for us.

A key point is that each species of bacteria has its own favorite food, and produces a unique combination of gases and SCFAs. People with IBS (and eating a FODMAPs-restricted diet) need a gut stocked with critters that like to ferment non-FODMAPS carbohydrates, don't produce gas, and do produce large amounts of desirable SCFAs. Oh, and it wouldn't hurt if they could also control gut pH, help the immune system function properly, and "box out" bad bacteria. And they should be safe, of course. Bifidobacteria appear to be the best candidates.

Enter probiotics. When we take probiotic supplements we are ingesting microbes that we think will help, in large enough quantities to have a medicinal effect. Probiotics in general show a lot of promise for treatment of IBS, but we have much, more more to learn about them. Specific probiotics that have been studied and have evidence showing a good treatment effect are: Bifidobacterium infantis (best), Bifidobacterium animalis, and VSL#3 (a patented blend of different species of bacteria).

People who are immunocompromised (due to illness or immune-suppressing drugs) or who are critically ill should not take probiotics without discussing the risks and benefits with a health care provider.

My next post will cover the nitty-gritty of how and when to take probiotics when using my FODMAPS-elimination diet program. Stay tuned!

Food: The Forgotten Factor in the Irritable Bowel Syndrome

To those of us with IBS, food is rarely forgotten, but medical professionals sometimes need to be reminded that it is a factor! An excellent review article, just published in Gastroenterology Clinics of North America, will do just that.  If you love science, or if you are one of my dietitian colleagues, it will be well worth your time to read the article. Or, scroll down for my summary!

Food: The Forgotten Factor in the Irritable Bowel Syndrome
Shanti Eswaran, Jan Tack, William D. Chey
Gastroenterology Clinics of North America - March 2011 (Vol. 40, Issue 1, Pages 141-162, DOI: 10.1016/j.gtc.2010.12.012)

Short version:

• Food molecules act as chemical messengers that activate nerves, muscles and hormones, influencing digestion, fluid balance and motility in the gastrointestinal system.
• There are a variety of possible adverse reactions to food. Some are immune mediated (classic food allergy or delayed- or cell-mediated hypersensitivity) and some are not (toxins, physical irritation, lactase insufficiency, fructose malabsorption, FODMAPS in general)
• People with IBS are probably especially sensitive to all of the above.
• There are a number of specific diets for IBS, including fiber supplements (may exacerbate problems), gluten restriction (may be a subset of IBS-D patients who improve with gluten restriction), sugar/carbohydrate restriction (in IBS patients, any form of carbohydrate malabsorption is likely to result in development of symptoms) and finally FODMAPS restriction (growing body of evidence to support efficacy, impressive symptom relief with this more holistic approach)
• IBS--Free at Last! is cited as a reference for details regarding the practical implementation of the FODMAP diet! Very exciting!

What is Fermentation?

What is fermentation and why should you care? If you have IBS or suffer from excess flatulence, bloating, or gassy abdominal pain, you can benefit from knowing a little bit about fermentation.

The gastrointestinal tract is populated by billions and billions of bacteria. That is normal. Fermentation is the breakdown of carbohydrates by these microbes. The bacteria need energy to survive, and they get it by consuming carbohydrates in the human diet. In the process, they produce hydrogen, methane and other gases. The gases make the intestines expand; picture a tube-shaped balloon expanding as it is blown up. The abdominal wall gently expands to accommodate this, and the gas is eventually either passed as flatus or absorbed into the blood stream. In IBS, the expansion of the intestine is experienced as a painful sensation. Why? Some possibilities:

• Some carbohydrates are fermented more rapidly than others (FODMAPs!); a diet loaded with FODMAPS might cause excessive gas production.
• Lactose and fructose (FODMAPs, again!) can be poorly absorbed in some people, which presents excess "food" to the intestinal bacteria.
• Fast intestinal transit time due to a virus, inflammatory bowel disease, celiac disease or non-FODMAPs food sensitivity. If the dietary carbohydrates are rushing past your small intestine before they can be absorbed, again, excess "food" may be presented to the bacteria in the large intestine.
• Tight clothing can prevent the natural expansion of the abdominal wall--consider this one if you've gained a few pounds and are still trying to fit into your skinny clothes.
• Traveling or at work? Maybe you are holding on to some of that gas you should be passing. Time for a quick "walk" around the block!
• Bacterial overgrowth can occur or bacterial growth can be present in the small intestine where it doesn't belong. This condition is known as small intestine bacterial overgrowth (SIBO) and is sometimes treated successfully with Rimaxifin as discussed in my previous post. It stands to reason than limiting fermentable carbohydrates (FODMAPs) would cut down on the gas that bacteria in either the small or large intestine.

Fructose Malabsorption and Depression

Do an internet search for the terms "fructose malabsorption" and "depression" and you will find a lot of buzz over the possibility that the two are linked. Google returned over 6,800 hits on this combination. The idea seems to be taking on a life of its own, and is treated as fact on a number of web sites and blogs. I wondered if there was any of that pesky old evidence on the subject.

I've spent several evenings poking around the internet, reading abstracts and peer-reviewed research reports, most of them published in Europe. In fact there are a number of interesting published research reports that suggest there may be a link worthy of further study. It is far from proven, however. The handful of studies that have been done, most by a particular workgroup at the University of Innsbruck, Austria, included a very small number of study subjects. The researchers have tried to discover whether there was an association between fructose or lactose malabsorption and depression. They did find such an association, but only in females. But the studies simply weren't designed to prove that fructose malabsorption causes depression. It is intriguing, though, isn't it?

The researchers did some more small scale studies to explore possible mechanisms for the fructose or lactose malabsorption-depression link. They have discovered that there may be an association between fructose malabsorption and lower levels of tryptophan, zinc and folate in the blood. It is the job of scientists to speculate about how these observations could all fit together, and speculate they do. Could these nutrients be poorly absorbed because the fructose malabsorption causes diarrhea and reduces contact time between the contents of the GI tract and the absorptive surfaces of the small intestine? Could unabsorbed sugars be interfering with the absorption of tryptophan? Could fructose malabsorption be encouraging small intestinal bacterial overgrowth (SIBO)? Could the lower serum levels of tryptophan, zince and folate cause depression?

There are far more questions than answers, here. Scientists are choosing their words with care, using the terms "may" and "suggest" and "associated with," and they point out that further studies are needed.

What is the take-away message here for people with fructose and/or lactose malabsorption? If you're a woman, removing excess amounts of these sugars from your diet might make you feel better mentally as well as physically! That's all, folks.

The report that started it all? Fructose malabsorption is associated with early signs of mental depression, Ledochowski M, Sperner-Unterweger B, Widner B, Fuchs D. Eur J Med Res. 1998 Jun 17;3(6):295-8.

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Fructose Malabsorption and Fructose:Glucose Ratio

What's up with the fructose:glucose ratio? If I experience dietary fructose intolerance, why can I tolerate fructose better if there is an equal amount of fructose in the meal?

First, let's recall the context here: the goal is to manage gastrointestinal symptoms, not to eliminate fructose, per se, from the diet. That's just not necessary (unless one has hereditary fructose intolerance, another subject entirely). Next, recall that high fructose foods include many fruits, honey, and sweetening ingredients such as high fructose corn syrup, crystalline fructose, and fruit juice concentrates.

The ability of the small intestine to absorb fructose is limited, at best. This was less of a problem years ago, when our intake of fructose was also limited! As recently as 30 years ago, the average U.S. intake of fructose was only 2/3 of what is is today, due to changes in the food supply. Imagine the distant past, when honey would have been a rare sweet treat, requiring feats of courage and strength to obtain. Cane or beet sugar and a wide variety of fruits would not have been available to most people in the world, except on rare occasions. Now, our diets contain lots of fructose, although over half of us can't fully absorb a 50 gram serving of fructose. Any time you are eating fructose faster than your personal ability to absorb it, the unabsorbed fructose will be carried on into the large intestine, where it is fermented by the resident bacteria, causing gas, bloating and altered bowel habits.

It appears there are probably two way fructose is absorbed through the cell walls of the small intestine. The first way is a low-capacity type of diffusion, in which a fructose molecule can pass through the cell wall on its own. The second mechanism is transport system that only works when there is one glucose molecule available for every fructose molecule. If there is no glucose-fructose pair, there is no absorption.

This explains why granulated sugar, which contains an equal amount of glucose and fructose is well tolerated in moderation, even by fructose intolerant individuals. Also, fruits such as berries, certain melons, and citrus fruits, which do not have an excess of fructose compared to glucose, can be tolerated in small servings. The fructose intolerant individual could still experience symptoms if very large portions of these "allowed" foods or beverages are consumed.

If you learn that you have dietary fructose intolerance, but would still like to consume high fructose foods, you might be able to do so if  you take a glucose/dextrose tablet along with the food, to improve the fructose:glucose ratio. These inexpensive tablets are sold at your local pharmacy along with diabetic supplies.

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Picture helpful to understanding FODMAPS

This picture may take a moment to download, but it is worth the wait. It uses a "bucket" analogy to illustrate how FODMAPS can cause IBS symptoms in sensitive individuals.

HFCS=high fructose corn syrup; FOS=fructo-oligosaccharides