Around 10 to 15 percent of Americans suffer from IBS, a broad term used to describe a cluster of persistent digestive symptoms, usually after more serious causes, such as celiac disease, have been eliminated. Why some people experience the often-debilitating effects of IBS is not understood, but there is now strong evidence that FODMAPs often trigger symptoms. These symptoms vary from person to person in frequency and severity. Symptoms triggered by FODMAPs usually come on at least 30 minutes after the food in question is eaten, as it takes time for the unabsorbed FODMAPs to reach the large bowel, where most of the symptoms are generated. Some FODMAPs (fructose, lactose and polyols) are poorly absorbed in some of us, while other FODMAPs (fructans and GOS) are not absorbed in any of us.
One of the key factors involved in the perception of symptoms is something called the “gut–brain axis,” a communication pathway between the nerves that surround the bowel and the brain. The large bowel is “designed” to blow up like a balloon when gas is produced by the bacterial fermentation of fiber, FODMAPs and so on. It’s normal and expected that the bacteria will produce gas. The body usually deals with this gas either via the back passage (with a “fart,” “flatus” or “wind”) or it crosses the intestine wall and dissolves in the bloodstream, then is carried up to the lungs and breathed out. Gas production is normal, and bowels blowing up and down like an inflating and deflating balloon is also normal.
Around 10 to 15 percent of Americans suffer from IBS, a broad term used to describe a cluster of persistent digestive symptoms, usually after more serious causes, such as celiac disease, have been eliminated.
In some people, such as those with IBS, however, the nerves within the stretch receptors surrounding the bowel don’t like the bowel blowing up like a balloon. These nerves have what’s called “visceral hypersensitivity,” which means they’re extra sensitive to stimuli that should really be considered normal. These ultrasensitive nerves send distress messages to the brain when the bowel is distended. The brain can do one of two things in response: recognize that these messages should be ignored, or over-interpret them and process them to generate symptoms (such as what happens in people with IBS). This nerve communication is the gut–brain axis, and in people with IBS the unhappy brain and gut can trigger IBS symptoms. In people without IBS, the gut–brain axis is functioning normally, there’s no visceral hypersensitivity, and the brain doesn’t over-interpret the messages, so symptoms aren’t usually triggered.
Other players are also involved in IBS, and may include abnormal types and/or amounts of bacteria in the large bowel and increased permeability of the lining of the bowels and an altered immune response. How the visceral hypersensitivity begins and the gut–brain axis becomes altered is not well understood – many people first experience symptoms after a bad bout of gastroenteritis, some after traveling overseas, some after a long or strong course of antibiotics, and some after a physical or emotional trauma. For others, however, there’s no obvious reason why their IBS started. Fortunately, the low-FODMAP diet is effective in resolving IBS symptoms in the majority of people who try it, regardless of the underlying cause.
Scientific studies have shown that apart from IBS symptoms, FODMAPs also trigger fatigue, lethargy and reduced concentration. Why this occurs is not well understood; however, the good news is a low-FODMAP diet has been shown to improve these symptoms in the many people with IBS who also suffer from fatigue and “brain fog.”
Fortunately, the low-FODMAP diet is effective in resolving IBS symptoms in the majority of people who try it.
There are many conditions that have symptoms similar to IBS. It is really important to try not to self-diagnose IBS, or any other condition, as they can all have different causes and different treatments. To make sure you are on the correct path for your symptom management, a proper diagnosis via a medical doctor is recommended. If you suspect you have IBS or an adverse reaction to foods, you should seek the advice of a medical practitioner, such as your general practitioner, a gastroenterologist, an immunologist or a registered dietitian, and discuss your symptoms.
Symptoms commonly associated with IBS are listed below. Please note, all of us can experience some of these symptoms from time to time; that is normal. However, when the symptoms are occurring frequently over a significant period of time (e.g., a few months), it is recommended you speak to your doctor about them, and request to start some investigations as to the cause.
Once you have a diagnosis of IBS, you should seek specific advice about modifying your diet from a qualified dietitian. Many possible food components can contribute to a food intolerance and symptoms of IBS, so it is recommended that you be assessed by a registered dietitian specializing in food intolerances.
Never trial a gluten-free diet to relieve your symptoms until you’ve been investigated for celiac disease, as this type of diet can interfere with obtaining accurate results (for more, see Celiac Disease below).
A dietitian may determine whether you have an intolerance by taking a dietary history. Before your appointment, it’s wise to keep a record of the food you eat in a typical week, and the symptoms you experience during those seven days. This is called a “seven-day food and symptom diary.”
Once you have a diagnosis, a registered dietitian will provide expert advice on which foods to limit and what to replace them with. (My team of dietitians at Shepherd Works offer Skype and/or telephone consultations for people living in the US; find out more by visiting my website www.shepherdworks.com.au. To find a registered dietitian in the US, visit www.eatright.org/find-an-expert.)
Once you know your food triggers you’ll need to restrict foods containing the problematic ingredients and become a careful reader of food ingredient labels. Good food planning and preparation are vital in ensuring you meet your nutritional needs and avoid unwanted abdominal distress. The severity of symptoms varies; some will need to avoid the problematic food completely, while others may only need to reduce their dietary intake.
When you cut out problematic foods, you need to replace them with healthy alternatives to avoid nutritional deficiency and poor health. A dietitian can assist you to make sure you don’t miss out on important nutrients.
CELIAC DISEASE
Celiac disease is estimated to affect about 1 percent of Americans. It is a medical condition of intolerance to dietary gluten. Gluten is the protein component of wheat, rye and barley (and, in some countries, is considered to be present in oats), and is found in derivatives of these, including triticale and malt. (Note that because gluten is a protein, it is not a FODMAP, all of which are carbohydrates.) In people with celiac disease, gluten causes an immune reaction that damages the small protrusions on the lining of the small intestine (the villi), flattening them and dramatically decreasing the ability of the intestine to absorb nutrients from food. Celiac disease is not a food allergy.
There’s currently no cure for celiac disease. The only treatment is a strict lifelong gluten-free diet (even if symptoms are mild or there are no symptoms at all). It’s not a trendy “fad” diet, but rather a real medical therapy for a real medical condition. A gluten-free diet is more restrictive and excludes more foods than a wheat-free diet. Regular bread, pasta, cereals, cakes, cookies, pizza, pastries and so on are all obvious gluten sources, but it can also be hidden in many foods, including commercially prepared condiments and sauces, gravies, candy, charcuterie and even beer!
Symptoms of celiac disease range from none at all to the following, with varying severity:
Because these symptoms are quite similar to those of IBS, it’s extremely important that anyone who has them be investigated for celiac disease before removing gluten from their diet. Even if you have been told you have, say, fructose malabsorption, that doesn’t mean you can’t also have celiac disease. Celiac disease should be investigated in all people with these symptoms.
The tests for celiac disease include blood test screening, but the gold standard remains a small intestine biopsy. A gene test (performed as a blood test) can be helpful to exclude celiac disease, since only people with the genes HLA DQ-2 or HLA DQ-8 can develop the disease. If you do have either of these genes, this doesn’t guarantee that you’ll get celiac disease – one third of the population carries one or both of these genes, but only about 1 to 2 percent of the population actually develops celiac disease.
The reason you should never trial a strict gluten-free diet is that if you actually have celiac disease, a proper diagnosis won’t be possible, as your small bowel may already have begun to repair itself as a result of the gluten-free diet. People being investigated for celiac disease still need to be consuming gluten in their diet.
It is also worthwhile noting that just like asthma and diabetes are two different conditions that can occur in the same person, celiac disease and IBS can occur in the same person, too. If you have been diagnosed with celiac disease and are strictly compliant with your gluten-free diet but still experience symptoms, you may have IBS. Consult a dietitian with experience in celiac disease, who will first check your diet for any accidental gluten intake and, if necessary, will teach you how to combine a gluten-free and low-FODMAP diet to manage your celiac disease and possible IBS.
There’s much greater awareness of the various dietary conditions these days, and diagnosis has been streamlined, but many people are still wrongly or poorly diagnosed, often after spending a great deal of time and money seeing numerous practitioners. For this reason, I’ve produced this flowchart to give you a good idea of what constitutes an effective and comprehensive approach to your symptoms.
Patient presents with IBS symptoms to health practitioner |
||
|---|---|---|
| ↓ | ||
| “Red flags” such as unexplained weight loss, recent onset of symptoms, blood in stools, raised inflammatory markers identified? | YES → | Medical investigations as appropriate |
| NO ↓ | ↙ | |
| Is patient consuming a gluten-containing diet? | NO → | Patient must undergo a gluten challenge, i.e., consume 4 slices of wheat bread a day for 6 weeks |
| YES ↓ | ↙ | |
| Undertake medical investigations for celiac disease | ||
| ↓ | ||
| Celiac disease diagnosis positive? | YES → |
Appropriate medical management Referral to a specialist dietitian for education in implementing a strict lifelong gluten-free diet |
| NO ↓ | ||
|
Referral to a specialist gastrointestinal dietitian educated in the low-FODMAP diet, and advised to reduce any obvious excesses, such as caffeine, alcohol and fat, if these are likely triggers Referral to psychologist and/or hypnotherapist if suitable |
||
| ↓ | ||
| Have symptoms improved satisfactorily after following the low-FODMAP diet properly for 6–8 weeks? | YES → |
Under the guidance of the specialist dietitian, undertake Step Two of the low-FODMAP diet, i.e., the reintroduction and liberalization of foods containing FODMAPs as tolerated. This is important to optimize variety in food choices while maintaining symptom control Also address nutritional adequacy |
| NO ↓ | ||
| Based on degree of symptom change (if at all), under the guidance of the specialist dietitian, manipulate dietary restrictions to identify other culprit foods/food molecules, e.g., a trial food-chemical elimination diet, or gluten-free diet alone or in combination with the low-FODMAP diet | ||
| ↓ | ||
| Have symptoms improved satisfactorily? | YES → | Specialist dietitian reviews symptoms and food intake. Advises how to restrict identified dietary culprits while still achieving nutritional adequacy |
| NO ↓ | ||
| Dietitian and doctor liaise and explain that IBS symptoms may not be caused by diet alone (or at all), and explain gastrointestinal physiology and how stress or anxiety affect symptoms. Maintain any useful dietary changes while achieving nutritional adequacy | ||
| ↓ | ||
| Consider other medical management | ||
FODMAPs are a collection of short-chain carbohydrates (sugars and related molecules) that occur naturally in many foods, and some can also be added to processed foods. Unlike many other sugars, FODMAPs are not absorbed in the small intestine, and continue their journey through the digestive tract to the large intestine. FODMAPs are then used as a food source by the bacteria that naturally live in the large intestine, producing gas. Additionally, FODMAPs are concentrated sugars (highly osmotic) in the bowel and can draw water into the bowel via osmosis. The increased gas and water in the intestines can make the bowels blow up like a balloon, and can also change the speed at which the bowel muscles work. These effects, in turn, can trigger symptoms such as bloating, distension, excess wind, diarrhea and/or constipation. FODMAPs can indeed trigger all the symptoms of IBS.
The word “FODMAP” is an acronym that describes a family of poorly absorbed, highly fermentable short-chain carbohydrates (sugars) and sugar alcohols, falling into five main classes. The acronym gives some hint about what happens to these molecules in the digestive tract, and also describes the size of these molecules – some are very short, some are longer. To understand the term, it’s important to know that “saccharide” means sugar, “oligo” means few, “di” means two or double, and “mono” means one or single. Note: not all carbohydrates are FODMAPs.
FODMAPs are a collection of short-chain carbohydrates (sugars and related molecules) that occur naturally in many foods, and some can also be added to processed foods.
Fermentable – FODMAPs are not absorbed in the small intestine and therefore travel into the large intestine where they can be broken down (fermented as a food source) by the bacteria that reside there.
Oligosaccharides – As “oligo” means few and “saccharide” means sugar, it makes sense that oligosaccharides are chains of individual sugars joined together. There are two oligosaccharide FODMAPs: fructans and galacto-oligosaccharides (GOS).
Disaccharide – This refers to the double sugar lactose.
Monosaccharide – This refers to “excess fructose,” in other words where fructose, a single sugar, is present in foods in amounts greater than glucose, another single sugar.
And
Polyols – These molecules, related to sugars, are called “sugar alcohols” (although they won’t make you intoxicated!), and include sorbitol, mannitol, maltitol and xylitol. Isomalt and polydextrose act in a similar way.
The low-FODMAP diet is used internationally as a treatment for IBS, as it’s the most effective diet for managing IBS symptoms. The low-FODMAP diet can also help people who suffer from some or all of these symptoms yet haven’t been formally diagnosed with IBS by their doctor.
The low-FODMAP diet has been embraced by sufferers of digestive symptoms from around the world and is also recommended by doctors because it’s backed by scientific evidence:
When people are first introduced to the low-FODMAP diet and discover foods such as wheat and onion are restricted, the first response is often shock, followed shortly after by disappointment, frustration and often grieving for the foods that are limited. By contrast, however, these negative feelings are often offset by the positive feelings of symptom management, a direct result of the FODMAP modification improving symptoms. For many, the changes are worth the sacrifice of restricted food choices, especially considering the strict restriction is only for six to eight weeks in most cases.
You can “cheat” on the diet – based on current knowledge, there is no damage caused to the bowels if you should splurge and eat foods that are high in FODMAPs – the worst that will happen is your symptoms will be triggered. It is your choice: if you are tempted by a high-FODMAP food, you can weigh the benefit of eating it versus the impact of the symptoms – sometimes you might think the food tempting you is worth the symptoms!
If you are really having difficulties adjusting, then ensure you talk to your health professional to discuss your feelings. If cutting out all high-FODMAP foods all at once (as is described in Step One of this book) doesn’t feel right for you, it might be more manageable and less burdensome for you to take a slower approach, cutting out one FODMAP group at a time over a few weeks, to gradually reach the restriction you need for your symptom relief. This diet is meant to be a positive change for your physical health (IBS symptoms). However, if it is causing too much stress and affecting your mental health, then a different approach may be needed for you. I recommend consulting with an experienced dietitian for individualized advice to meet your needs – you can still achieve your goals, it may just be via another route. Gut-focused clinical hypnotherapists and other IBS-focused psychologists may also be able to assist. It is important to manage worries, as stress, depression and anxiety can all be independent triggers for IBS symptoms.
You can “cheat” on the diet – based on current knowledge, there is no damage caused to the bowels if you should splurge and eat foods that are high in FODMAPs – the worst that will happen is your symptoms will be triggered.
This book will assist with managing those feelings. It won’t take you long to get through Step One, and you’ll be through to the reintroduction process, and well into Step Two before you know it, enjoying your own liberalized FODMAP-modified eating plan where you don’t have to restrict so much, and you can enjoy a greater variety of foods. This book will help your longer-term eating habits by making them as non-restrictive as possible. I firmly believe that.
“ I have Crohn’s and as a result have had a total colectomy. For five years I have had all kinds of trouble with gas and output via my stoma. Your diet has solved it – I really wish that I had known about your diet while I still had a colon because I do not think my Crohn’s would have been so terribly painful and quite so debilitating. Thank you so much.
I am, however, more grateful for the impact on my twenty-one-year-old daughter’s life. All through her teenage years she had terrible trouble with pain, bloating, nausea and the trots. We had her tested because I was terrified she had Crohn’s. She doesn’t have any inflammatory bowel disease – there was an unconvinced diagnosis of possible IBS.
I FODMAP’d her diet and the massive improvement in the quality of my daughter’s life is tremendous, just in time for her going to college. She no longer spends ninety minutes in the bathroom every morning or bloats, etc. It removes the unpredictability of her guts. Having eliminated the FODMAP group of symptoms we have also been able to identify that she is lactose-intolerant. She is a different girl and at last has the chance to reach her full potential and also enjoy life. I am so very very grateful to you, Dr. Shepherd – in our house you are a goddess.
Thank you!!! ”
