By: Lindsay Goddard, MS, RDN, LDN
Licensed & Registered Dietitian/Nutritionist
Up to 70 million Americans live with digestive conditions and emerging research shows that FODMAPs (rather than gluten or lactose) may be the mysterious cause for gastrointestinal symptoms in some people.
What are FODMAPs?
FODMAPs stand for; Fermentable Oligo-Di-Monosaccharides And Polyols, which are specific types of carbohydrates (sugars) found in a wide range of foods.
Normally FODMAPs are digested and absorbed in the small intestine. However, new research shows that in some people the carbs are poorly absorbed in the small intestines, which means they travel to the colon and are fermented/digested there instead. Once there, the carbs (being “osmotic”) pull water into the intestines, which leads to excess fluid build-up and results in bloating, cramping, and/ or diarrhea (1).
Gut bacteria, and its role in our health has become a very popular topic these days. And it applies here too. Our “good” gut bacteria are vital to breaking down FODMAPs (among many other nutrients), and in fact some FODMAPs are the bacteria’s main source of food (also known as prebiotics, e.g. found in honey and onions).
If the GI tract doesn’t have enough “good” bacteria, it can’t break down or absorb the FODMAPs, which is why symptoms may occur. To some people this may be “normal”, but feeling bloated, gassy, constipated, cramped, and/or having diarrhea consistently is not normal. Occasional symptoms can be chalked up to eating something that didn’t agree with you, but every day symptoms affect your quality of life.
What foods contain FODMAPs?
Lactose, Fructose, Fructans, Galactans and Polyols are the different types of FODMAPs found in a variety of foods. Below are foods naturally high in FODMAPs (1,2,3). Serving size is an important thing to consider with FODMAPs because certain high FODMAP foods may be tolerated at very small serving sizes, just as low-FODMAP foods may NOT be tolerated at very high serving sizes (e.g. almonds).
Do GN proteins contain FODMAPs?
- GN rice protein (all flavors) are low-FODMAP at all serving sizes.
- GN pea protein (all flavors) are low-FODMAP at 2 servings (scoops) maximum.
Do I need to avoid FODMAPs?
A low FODMAP diet can be beneficial if you are experiencing constant gas, bloating, cramping, and/ or diarrhea with no medical diagnosis. The diet can also be used to help control the symptoms of digestive conditions such as Irritable Bowel Syndrome (IBS) or Irritable Bowel Diseases such as Crohn’s or Ulcerative Colitis (2).
Since FODMAPs are found in a wide range of foods (including many healthy fruits and vegetables), avoiding them can be very restrictive in nature. If you feel it could help with your symptoms, you should consult with a healthcare professional like a Registered Dietitian for proper guidance. The idea behind the diet is to help find the food sources causing these uncomfortable side effects.
Although research has shown that a low-FODMAP diet can be beneficial, it has also been suggested that fixing the gut bacteria can be just as helpful.
How does the low-FODMAP diet work?
It starts off by cutting out ALL of the foods that contain FODMAPs. After 6 weeks, foods from one group of the FODMAP list are eaten in small amounts, one at a time. Three days after the first introduction, another group can be started in the same way (1, 2).
It‘s helpful to keep a journal of the foods that are eaten, and write down any changes or symptoms that are felt within 48 hours from the meal. This method allows for foods that cause the symptoms to be easily recognized.
What are the risks of a low-FODMAP diet?
Although there are benefits to the diet for some, there are also some risks to consider. Restricting such a wide range of foods, excludes a number of vitamins and minerals, so deficiencies could begin to occur.
Another really important nutrient that is excluded is fiber. Fiber contained within these carbohydrates is a component of food that the body cannot digest on its own, and is found almost exclusively in plant based foods. For these reasons, a low FODMAP diet should not be followed for a long period of time, nor without the help of a healthcare professional, such as a Registered Dietitian/Nutritionist (RDN).
Due to the restrictiveness, the diet should only be followed strictly for 6 weeks and no longer.
Are FODMAPs related to gluten?
FODMAPs are not the same as gluten. Gluten is a protein found in grains like barley, rye, oats (sometimes) and wheat, whereas FODMAPs are carbs. These two types of food classes are digested differently, and therefore affect the body differently. In other words, if you have issues with gluten, it does not mean you automatically have problems digesting FODMAPs, or vice-versa, a problem with FODMAPs, does not mean you must also avoid gluten. The only documented relationship between FODMAPs and gluten is in the case of Celiac Disease, when the intestinal lining has been damaged from a gluten allergy resulting in intolerance to lactose, or dairy products.
Most gluten containing grains are in the fructan group of FODMAPs, and should be avoided during the low FODMAP diet (but it is not due to the gluten content), and if found to be an irritant, avoided all together. Remember; “Gluten- free” means foods are generally “WHEAT- free”, but “Gluten –free” does NOT mean “FODMAP –free” because there are still a lot of other ingredients to consider.
Oats (if stated “gluten-free”) are still ok to consume while on the FODMAP diet, just not wheat, rye, or barley. Oats can be a little tricky, as technically they do not contain gluten, but often times, they are processed in a facility that works with gluten, voiding the “gluten-free” claim. When buying or eating oats, make sure they say “gluten-free”.
- Stanford Medical Center. The Low FODMAP diet. 2012. https://stanfordhealthcare.org/content/dam/SHC/for-patients-component/programs-services/clinical-nutrition-services/docs/pdf-lowfodmapdiet.pdf
- Scarlata, K RDN. FODMAPS. 2015 http://www.katescarlata.com/fodmaps/
- Thomas JR, Nanda R, Shu LH. A FODMAP diet Update: Craze or Credible. Practical Gastroenterology . December 2012. p 37-46.