Low-FODMAP Diet – Foods to Avoid in IBS & Bloating

Short-Chain Carbohydrates May Cause Chronic Bloating and Diarrhea

It was found out that certain short-chained carbohydrates can cause chronic diarrhea, abdominal bloating, gas or other gastrointestinal symptoms in individuals, diagnosed with:

• Dyspepsia (indigestion)
• Irritable bowel syndrome (IBS) or functional bowel disease (FBD)…

…or aggravate symptoms of:

• Lactose intolerance
• Fructose malabsorption
• Small intestinal bacterial overgrowth (SIBO)
• Celiac disease
• Inflammatory bowel disease (Crohn’s disease, ulcerative colitis)
• Dumping syndrome (rapid gastric emptying)

These carbohydrates were named FODMAPs.

What are FODMAPs?

FODMAPs (Fermentable Oligo-, Di-, and Mono-saccharides, And Polyols) are short-chain carbohydrates that are:

• Osmotically active, so they may drag water from intestinal vessels into intestinal lumen, thus causing diarrhea
• Easily degradable (fermentable) by intestinal bacteria, and yielding large amount of gases like hydrogen, carbon dioxide, or methane thus causing bloating

FODMAPs include:

• Oligosaccharides:
  • Fructans- chains of fructose with one glucose molecule on the end. Only minimal amounts of fructans may be absorbed in human intestine. They may interfere with absorption of fructose, thus aggravating symptoms in fructose malabsorption. Fructans-rich foods are: wheat (white bread, pasta, pastries, cookies), onions, and artichokes; other not commonly problematic foods with fructanes are asparagus, leeks, garlic, chicory roots and chicory based coffee substitutes. Fructans with over 10 molecules of fructose in a chain are known as inulins and those with less than 10 fructoses are referred as fructo-oligosaccharide (FOS) or oligofructose. Fructans cause problems mainly in fructose malabsorption.
  • Galactans (like stacchyose and raffinose) are chains of fructose with one galactose molecule on the end. They act much like fructans. Main galactans-rich foods are legumes (soy, beans, chickpeas, lentils), cabbage and brussel sprouts.
• Disaccharides:
  • Lactose (milk sugar). Lactose is in dairy products, but it may be also found in chocolate and other sweets, beer, pre-prepared soups and sauces, etc. Lactose is poorly absorbed in lactose intolerance, SIBO and in small intestinal inflammation (Crohn’s disease, celiac disease).
• Monosaccharides:
  • Fructose (fruit sugar). Fructose-rich foods are honey, dried fruits like prunes, figs, dates, or raisins, apples, pears, sweet cherries, peaches, agave syrup, watermelon, papaya, etc. Fructose is often added to commercial foods and drinks as high fructose corn syrup (HFCS). Fructose causes symptoms even in healthy people, if ingested in excess, especially in fructose malabsorption, but also in SIBO.
• Polyols, also known as sugar alcohols (appearing as artificial sweeteners in commercial foods and drinks):
  • Sorbitol  may appear in “sugar-free chewing gum”, “low calorie foods”; naturally it appears in stone fruits: peaches, apricots, plums, etc).
  • Xylitol naturally apears in some berries. A pack of chewing gum containing sorbitol or xylitol may cause symptoms in a healthy child and especially in persons with fructose malabsorption or SIBO.
  • Other polyols:mannitol, isomalt, erithrytol, arabitol, erythritol, glycol, glycerol, lactitol, ribitol, etc. may be problematic in fructose malabsorption and in SIBO.

Possible Symptoms of FODMAP-Rich Diet

Excessive FODMAPs ingestion may cause:

1. Diarrhea, since they are osmotically active, so they drag water from the intestinal vessels into the intestine
2. Bloating and flatulence, since they are broken down (fermented) by intestinal bacteria to gases like hydrogen, carbon dioxide or methane
3. Abdominal pain
4. Unintentional weight loss
5. Symptoms of vitamin and mineral deficiency
6. Headache, lethargy, depression

Approach to Low-FODMAPs Diet

In unexplained chronic diarrhea or bloating, FODMAPs should be considered as a possible cause, so their amount in the diet should be LIMITED (not necessary totally excluded).

General approach is to take off as much as possible FODMAPs from the diet for six to eight weeks. If FODMAPs are the cause of the symptoms, these should lessen considerably in the first week. Additional weeks of diet bring some rest to the small intestine and cause reduction of overgrown intestinal bacteria.

After six weeks, some foods that will least likely cause symptoms can be introduced back into the diet (diet challenge), one type of food every fourth day. For example, on the first day of the seventh week, a piece of food low in lactose, like yoghurt, can be tried, and if in the next 72 hours no symptoms appear, other dairy products can be tried, and waited 72 hours again. If still no symptoms, it’s likely that dairy is not problematic food, or at least not problematic when taken in limited amount. If symptoms appear, this speaks for lactose intolerance, so dairy should be avoided and next type of foods tried. This can be some low-fructose food like banana, then after 72 hours orange and then other foods with increasing amount of fructose. If someone can eat 5 prunes, it’s not likely he/she has fructose malabsorption. 

A registered dietitian may be needed to give instruction about introduction of the low-FODMAP diet and diet challenge. 

How Long Should a Low-FOODMAP Diet Last?

When problematic FODMAPs are identified, some persons will need to strictly avoid them for life, if they wants to be symptoms free, others will be able to ingest them in limited amount after weeks of diet. General rule is: do not eat FODMAPs-rich foods in great amount in one sitting and do not eat them every day.

If Low-FODMAP diet doesn’t help, testing for food allergies, dumping syndrome, celiac disease, and inflammatory bowel disease (Crohn’s disease) should be considered.

Can Low-FODMAP Diet be Dangerous?

Low-FODMAP diet should not be introduced by any person with diabetes, hypoglycemia or other metabolic disorders, or in malnutrition, without prior consultation with a doctor. It may be necessary to interrupt Low-FODMAP diet in any severe acute disease, after injury or surgery and in other urgent situations.

None of FODMAPs (fructans, galactans, fructose, lactose, polyols) is essential nutrient for human though, meaning they are not necessary for life.  

Foods to Avoid in IBS

Foods that irritate individuals diagnosed with IBS, differ from person to person. It was found out that in many of them FODMAPs-rich foods are the culprit (1).

RElated Articles:

Find a Causes of Loose Bowel Movements From Medical Symptoms
Bowel Anatomy, Motility, Digestion & Gut Flora
Comparison of Normal and Loose Bowel Movements
Yellow Bowel Movement
Green Bowel Movement
Black Bowel Movement
Mucus In Bowel Movement

References:

1. Low-FODMAP diet (healthsystem.virginia.edu)
2. Polyols – sugar alcohols (sugar.org)