1. The Effects of a Low-FODMAP Diet on Treatment of Irritable Bowel Syndrome in Patients
Melanie Palmer

2. What is Irritable Bowel Syndrome (IBS)?
50% of all cases seen by gastroenterologists
Discomforting GI symptoms experienced every day:
Bloating
Abdominal pain
Constipation and/or diarrhea
Four Classes of IBS: IBS-C, IBS-D, IBS-U, IBS-M
1. While it accounts for 50% of all cases this number could really be higher since not all adults seek treatment for their condition. In fact while the prevalence is in the US only 5-7 percent are diagnosed.
2. This is because the symptoms are not alarming and they are also ones that are embarrassing and uncomfortable to talk about.
3. When diagnosed with IBS the patient can be classified in one of four classes….

3. The FODMAP diet and some examples
Oligosaccharides
Wheat, onion, garlic, most dried fruit, legumes
Disaccharides (Lactose)
Dairy products
Monosaccharides (Fructose)
Mango, cherries, honey, asparagus, snap peas
Polyols
Blackberries, sorbitol, mannitol, xylitol, Isomalt, cauliflower
While a combination of the many treatments for IBS is most effective I am just going to go over one which is the FODMAP diet.
Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols
Short chain carbohydrates
not fully absorbed by the body
fermented in the gut
While is shouldn’t be accepted as a lifestyle the FODMAP diet is a key treatment because 2/3 of people who have IBS say their discomfort comes from food they eat

4. Gas Production Each IBS subtype has a different mechanism (Halmos)
Gas production provide more insight on the differing mechanisms (Ong)
While both groups showed an increase in hydrogen production on both diets, the IBS group had the higher increase on both diets.
What goes in, must come out. Gas production is the most common symptom not only in IBS patients but also in healthy patients.
By using an Australian diet and a low FODMAP diet Halmos found that on top of IBS subjects having different mechanisms than healthy subjects… (first bullet) And mechanism means how well a GI tract is regulated by bacterial metabolism.
Even though this first study wasn’t able to find out the why these mechanisms occur, other studies were able to by measuring gas production in healthy and IBS subjects.
First they measured hydrogen production which was found in all healthy and IBS subjects. They found that… third bullet.

5. Breath Methane Production
Then they measured methane production.
These graphs show that there is less methane production in healthy subjects and more methane production in IBS subjects on the high FODMAP diet. Methane production on the low FODMAP diet is actually about the same except for those last 5 hours in the healthy group.
Healthy High to Low increases bacteria richness and diversity because gut environment goes from being more acidic to less acidic. The more bacteria the more gas production.
IBS High to Low decreases the amount of easily fermentable foods for bacteria to ferment. Since people with IBS will most likely have bacterial overgrowth, decreasing the fuel for the bacteria will see a reduction in symptoms. This information is important for IBS-C patients because…
High FODMAP
Low FODMAP
High FODMAP
Low FODMAP

6. Gas Production continued
Methanogenesis = slower transit time in the colon
Low FODMAP not for IBS-C, but more for IBS-D
These graphs display all the different subtypes
Does NOT distinguish each of the subtypes’ different mechanisms
Methane production, which is seen more in low FODMAP diets, is linked to slower transit time in the colon. But that doesn’t mean IBS-C subjects should eat a high FODMAP diet, instead they will need to incorporate other treatments into their lifestyle.
This shows how each IBS subtype can have different mechanisms so some IBS subjects may respond better to a low FODMAP diet than others, such as IBS-D individuals who are in need of a slower transit time in their colon.
The next graph gives you a better visual about how each subtype can have different mechanisms because the previous graphs showed all the subtypes together without distinguishing between each subtype.

7. Diversity in Bacterial Mechanisms
Significant results were not found in IBS because many of the individual lines have different ending points showing that gas production increase in some, stay the same in some and decreased in others. The lines of the healthy individuals, however, end in one specific area for the most part showing the gas production slightly decreased when going to the high FODMAP diet. Therefore the result of the healthy individuals was significant. This shows that the mechanisms in the healthy group are all similar while in the IBS group there are different mechanisms.

8. Parting Comments
More research is necessary to draw definite conclusions BUT all analyzed studies found significant information on IBS mechanisms
New information encouraging because every new finding increases the quality of life in some way
Although these results offer some insight into this complex and vague disorder much more research has to go into this area. While little is know about IBS, every new piece of information is still progress, offering hope and encouragement to increase the quality of life of IBS sufferers.