FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. This is yet another category of foods some people can have problems with. This is especially true with those who have irritable bowel syndrome (IBS). And some people with thyroid and autoimmune thyroid conditions should be cautious about eating foods high in FODMAPs.
Before I discuss who can benefit from a low FODMAP diet, let’s first discuss why some people have problems consuming these foods. Certain conditions such as IBS involve imbalances in the gut flora, and there is a higher prevalence of small intestinal bacterial overgrowth (SIBO). I have written a separate article entitled “SIBO and Thyroid Health“, and so I’m not going to discuss SIBO in this post. In any case, certain changes in the gut flora causes the person to react differently to specific types of foods. A study conducted a few years ago confirmed that FODMAPs are poorly absorbed in the small intestine (1). But once again, this doesn’t pertain to everyone, as only a small percentage of people need to eat foods low in FODMAPs.
What Are The Richest Food Sources of FODMAP Carbohydrates?
I came across a table from a well-researched journal article which lists the richest food sources of FODMAP carbohydrates (2). When you look at the table you’ll see that there are six categories of FODMAPs. These include Fructo-oligosaccharides (fructans), Galacto-oligosaccharides (GOS), lactose, fructose, sorbitol, and mannitol. You’ll also notice that some of the foods which fall under the different categories include wheat, rye, onions, garlic, legumes, milk, honey, apples, watermelon, mushrooms, and cauliflower.
Many people reading this are already on a restrictive diet, as some are gluten and dairy free, others might be grain free, of course vegans and vegetarians don’t consume meat, etc. And so it might be frustrating to realize that there is another category of foods you might need to avoid. Although those people following a gluten and dairy free diet are already avoiding wheat, rye, milk, and other foods which fall within these two categories, they might be consuming legumes, apples, garlic, and some of these other foods on a regular basis. Just remember that most people with thyroid and autoimmune thyroid conditions don’t need to follow a low-FODMAP diet.
In addition, those who should eat low FODMAP foods might not necessarily need to avoid foods in all of the categories listed in the table. The bad news is that foods which fall into the fructans and GOS category will need to be excluded by anyone trying to follow a low-FODMAP diet, as these foods are always malabsorbed and fermented by intestinal microflora (2). On the other hand, some people will be able to tolerate foods such as honey, apples, pears, and watermelon. For a more comprehensive list click here. For the most part I agree with the list, although this lists coconut as a low FODMAP food, while other sources list coconut milk and other sources of coconut as high in FODMAPs. So this is something you might need to experiment with, or if you want to play it safe you can avoid coconut milk.
Which FODMAP Foods Should Be Avoided?
But how does someone who needs to follow a low-FODMAPs diet know which foods they can and can’t eat? Well, as I just mentioned, everyone who needs to follow a low-FODMAPs diet will probably need to avoid eating foods in the fructans and GOS category. As for whether they are able to eat foods in the other categories, there are a few different ways to find this out. One way is through a breath test. For example, if someone wants to find out if they have problems absorbing fructose then they can do a breath test to determine this. They can also choose to do a breath test for lactose and sorbitol. There currently isn’t a breath test available for mannitol.
Another way to determine if someone can tolerate these other foods is through an elimination diet. And so what someone can do is to avoid all foods high in FODMAPs for one month, and then slowly reintroduce one at a time to see how they respond. Once again, if they know they need to follow a low-FODMAPs diet but aren’t exactly sure which foods they will need to avoid, just remember that everyone who needs to be on a low-FODMAPs diet will need to avoid foods in the fructans and GOS category. But how about if someone loves apples, pears, and watermelon and wants to see if they can tolerate these foods? After avoiding them for one month the person will want to reintroduce one food at a time for at least three consecutive days and see how they respond. So for example, they might want to start with apples, as perhaps they will want to eat an apple or two daily for three days in a row and see if they have a negative reaction. If all goes well then they are probably fine eating that food, and can then try reintroducing pears. On the other hand, if they experience symptoms then they will want to avoid eating apples, and will want to wait until the symptoms subside before reintroducing pears.
Do You Need To Be On A Low-FODMAP Diet?
At this point you might be wondering whether you need to be on a low-FODMAP diet. After all, I discussed what FODMAPs are, and I also mentioned how people who follow a low-FODMAP diet need to avoid certain foods but might be able to tolerate other “FODMAP foods”. However, I haven’t mentioned who should follow such a diet. Should all people with thyroid conditions follow this type of diet? Or perhaps only those with autoimmune thyroid conditions such as Graves’ Disease and Hashimoto’s Thyroiditis?
Well, anyone who is certain that they have IBS will want to experiment with a low-FODMAP diet, as most people who do this will notice a significant improvement in their digestive symptoms. However, even if someone isn’t sure whether or not they have IBS but if they are experiencing digestive symptoms such as frequent bloating and gas, stomach pain, and other digestive symptoms, then it still might be a good idea to consider experimenting with this type of diet. As I mentioned earlier, someone can consider going on an elimination diet, but if they have a lot of digestive symptoms I would recommend for them to avoid all of the common allergens (i.e. gluten, dairy, corn, soy, eggs, etc.) for 30 days, and they can also follow a low-FODMAP diet during this time, and then after the 30 days then can slowly reintroduce these foods one at a time.
I realize that this would be a very restrictive diet, but if you are sensitive to any of these foods then it is important to eliminate them from your diet. Of course another option is to just focus on eliminating the common allergens first and not worry about high FODMAP foods initially. After all, if you don’t have IBS then you very well might be fine eating these foods. And just remember that if you need to follow a low FODMAP diet this isn’t necessarily permanent. For example, if someone has intestinal dysbiosis and as a result they’re unable to tolerate high FODMAP foods, then correcting the intestinal dysbiosis will most likely allow them to eat these foods again.
So hopefully you have a better understanding about what FODMAPs are, and why some people have problems with these foods. The six categories of FODMAPs include fructans, GOS, lactose, fructose, sorbitol, and mannitol. Those who need to follow a low FODMAP diet don’t necessarily need to avoid all of these foods, and they might need to either do a breath test to determine if they have problems absorbing certain foods, or they can simply follow an elimination diet. Fortunately most people with a thyroid or autoimmune thyroid condition don’t need to follow a low-FODMAP diet, but if someone is having a lot of digestive issues and eliminating common allergens such as gluten, dairy, eggs, and corn doesn’t help, then it’s something to consider.