According to the CDC, over 51 million visits to physician offices, outpatient clinics and the emergency room were related to digestive disorders. It’s a broad category, and one that has a lot of difficult to diagnose and manage maladies. Within digestive disorders is a category called functional GI disorders. This means that the GI tract isn’t functioning normally – despite the fact that there is no actual damage to the GI tract.
One functional GI disorder is irritable bowel syndrome, or IBS, which impacts about 20% of American adults (1). IBS can be defined as “a disorder in which abdominal discomfort or pain is associated with a range of symptoms. Typically, these include intermittent abdominal pain accompanied by diarrhea, constipation, or alternating episodes of both. Other symptoms may also be present.” (source: IFFGD).
Symptoms can vary dramatically from person to person, so there isn’t a one-size fits all approach to handling them. There are lifestyle and medication treatment options, but dietary intervention is among the most important. One of the emerging ways to manage IBS is through the FODMAP diet. The FODMAP diet originated in Australia, and has become increasingly popular in the past decade. One study done in Australia indicated that 86% of IBS patients were able to improve their symptoms by following a diet that is low in FODMAPs versus the 49% of patients who received the standard diet therapy (2).
FODMAP is an acronym that refers to Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. Yikes, that’s a mouthful. Basically, it is specific types of carbohydrates that easily undergo fermentation: fructans, galactans, lactose, fructose, and sugar alcohols.
Let's dig into that a little more...
Where are FODMAPs found in the diet?
Lactose – milk, yogurt, cottage cheese, ice cream, condensed milk
Fructose – honey, high-fructose corn syrup, agave, table sugar, apples, pears, mangoes
(note that foods with a 1:1 ratio or higher of glucose to fructose are generally well-tolerated, which means not all fruit must be eliminated!)
Fructans – wheat, inulin, chicory root, onions, garlic
Galactans – lentils, chickpeas, kidney beans, broccoli, soy-based products
Polyols – sugar alcohols like mannitol, sorbitol, xylitol
Why are FODMAPs problematic?
These carbohydrates are small chain carbs that can wreak havoc in a couple of different ways for people with sensitive GI tracts:
FODMAPs pull water into the small intestine.
If you’ve got a GI tract that tends to move quickly, this can contribute to diarrhea, as the water isn’t reabsorbed before being excreted. If you tend to fall on the opposite end of the spectrum, and your GI doesn’t move quickly enough, this means you’ve got water sitting in your intestine. Bloating and discomfort, oh my.
FODMAPs are poorly digested.
When food is poorly digested by humans, it is readily available to the bacteria that live in your gut. This is normal! Those bacteria also create vitamins (biotin and K), and help support a healthy immune system. The problem is that the bacteria “digest” the food through fermentation, which produces gas. If your GI tract is compromised or unhealthy, this gas can really accumulate – causing bloating, pain, and cramping.
Is this right for me?
First of all, don’t self-diagnose! Talk with a professional – a dietitian or a physician – about your symptoms and make sure you rule out other disorders.
To find out if FODMAPs are a problem for you, elimination is the easiest way to go. Following a very low FODMAP diet for 2-4 weeks can help chart symptoms and see if there is an improvement in bloating, diarrhea, and/or constipation. If you do not notice a change in symptoms after a month, this probably isn’t the right diet for you, and IBS may not be the problem – go back to the doctor!
Once you have experienced life without the symptoms, you have a couple of choices. You can continue to follow the very low FODMAP diet for life, or you can try adding in some higher FODMAP foods to see what your body can handle. For instance, some people can handle the lactose, but not fructans and polyols. Following a more restrictive diet than your body requires can be difficult at best, and can lead to deficiencies at worst.
You said something about wheat - is this gluten-free?
Many people with GI distress first try a gluten-free diet, as that is a common diet trend right now. Some experience relief of symptoms, but if IBS is the issue, many won't experience relief because of an important distinction. Gluten is a protein, while FODMAPs are carbohydrates. Therefore, intolerances to gluten will be for very different reasons than intolerances to FODMAPs.
That said, fructans are found in wheat and barley, which means that a gluten-free diet will eliminate those fructans. However, it will not address the rest of the FODMAPs. For instance, many gluten-free items are sweetened with honey, pear concentrate, or agave.
You mentioned dairy - can I have whey protein powder?
This distinction between protein and carbohydrate is also relevant to dairy products. A low FODMAP diet does not mean avoiding the milk proteins whey and casein. While you could just eliminate all products that contain milk, that might be more restrictive than you need to be.
Whey protein powders are likely acceptable for those following a low FODMAP diet - however, be wary of those that use artificial sweeteners. Also, since most animal sources of protein have zero carbohydrates, protein shouldn't be an issue with this diet - unless you are vegetarian.
Dietary concerns and disclaimer
Please remember that this is an informational blog, and is not intended to diagnose or treat any medical condition. The FODMAP diet is not the only dietary intervention for dealing with IBS. While I am a dietitian, I am (probably) not YOUR dietitian. Don't use this in place of medical care.
It is important to work with a dietitian on the low-FODMAP diet, because depending on which FODMAPs are restricted long-term for you, getting enough fiber, vitamin D, and iron could all be a concern.
I'm intrigued. Where can I learn more?
A few blogs written by dietitians that I really like for FODMAP-friendly recipes and advice:
- complete list of foods to enjoy and avoid when eliminating FODMAPs
1. National Digestive Diseases Information Clearinghouse. Irritable bowel syndrome. NIH Publication No. 07-693. September 2007. Available at: http://digestive.niddk.nih.gov/ddiseases/pubs/ibs
2. Staudacher HM, Whelan K, Irving PM, Lomer MC. Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. J Hum Nutr Diet. 2011;24(5);487-495.