low FODMAP diet

Is It the Gluten or the FODMAPs? – A Confusion, Explained

A common misconception about the low FODMAP diet is that it is a gluten-free diet. This is understandable as gluten-containing grains - wheat, barley, and rye - are greatly reduced or avoided during the elimination phase. For some people, these foods trigger common digestive symptoms (gas, bloating, abdominal pain, constipation or diarrhea). What is it in these foods that is responsible for the symptoms? Let’s dig in.

Gluten vs Fructans

Gluten is the main protein in wheat, barley and rye and needs to be avoided by people diagnosed with celiac disease. People with non-celiac gluten sensitivity (NCGS), a newly recognized condition that occurs when someone has a reaction from eating gluten but does not have celiac disease or a wheat allergy, also feel better when avoiding these grains and their products. These conditions are typically diagnosed by a gastroenterologist. Finally, people with a wheat allergy need to avoid all varieties of wheat (including spelt, kamut, einkorn, farro/emmer and triticale).

Fructans are a type of carbohydrate in gluten-containing grains, one of the FODMAPs (within the larger category of oligosaccharides, the “O” in FODMAP – more on this topic in a future article of my FODMAP Series). The common confusion comes from the fact that both gluten and fructans co-exist in wheat, barley and rye. The reason why these grains are reduced in the low FODMAP diet is that the fructans are poorly digested in people with IBS and may trigger symptoms. During the elimination phase, gluten-free grains like rice, quinoa, buckwheat and millet become a staple but small amounts of wheat can still be included. The main wheat-containing food allowed is true sourdough bread, as the fructans have been “digested” by the live cultures during a long process of fermentation, which reduces the fructan content of the bread. Soy sauce and even one small slice of regular wheat bread are usually tolerated and considered low FODMAP. In conclusion, the low FODMAP diet is not a gluten-free diet.

Not all gluten-free products are low FODMAP

During the elimination phase of the low FODMAP diet people rely on gluten-free grains and some gluten-free alternatives to bread, pasta, crackers and cookies assuming these are low in FODMAPs. It is important to point out that not all these packaged products are necessarily low in FODMAPs. When looking at a gluten-free product you need to become an expert label reader. Although the main flours used are low FODMAP (rice, tapioca, cassava), there are very often high FODMAP ingredients such as honey, agave, pear or apple juice (used as sweeteners), inulin or chicory (added to increase the fiber content) and others.

Take home message

Many people report feeling better on a gluten-free diet but don’t necessarily know why. Is it because they are sensitive to gluten, or the fructans? If you are one of them, I strongly encourage you to get a proper diagnosis first. If celiac disease or NCGS are diagnosed, then you will know that you need to avoid gluten-containing grains and their products. If you are found to have a wheat allergy, you will need to avoid all wheat products.

If you don’t have any of these conditions or continue to have symptoms on a gluten-free diet, the fructans (FODMAPs) may be to blame. Working with a dietitian to identify the source of the problem may help you liberalize your diet and find that you don’t need to unnecessarily avoid all gluten-containing grains and products. Interestingly, a recent study from Monash University (Biesiekierski et al, Gastroenterology 2013) found that only a small percentage of the subjects who had both IBS and NCGS were indeed sensitive to gluten (8%) but all felt better while eating a low FODMAP diet, suggesting that the FODMAPs had the greatest impact in their digestive symptoms.

5 Myths about the Low FODMAP Diet…Debunked!

1.     It’s a life-long diet

This is perhaps the most common misconception: that you should follow a low FODMAP diet for the rest of your life. This is just a temporary, learning diet and the “low FODMAP” part refers to the first phase of the diet, when you eliminate all high FODMAP foods. As soon as symptoms are reduced and you feel better, you need to re-challenge those foods gradually and systematically to find out your personal triggers. You can then craft your personalized FODMAP diet. Even then, you are not done. As symptoms wax and wane, you are encouraged to re-challenge more foods every 3-6 months.

2.     It’s the same for everyone

I often hear people tell me their doctor gave them a handout and told them to follow the low FODMAP diet. Period. It’s not that simple! This is not just a list of foods to avoid and foods to eat. Sure, a few foods have negligible amounts of FODMAPs and are “included” whereas other are high in FODMAPs and “excluded”, at least during the elimination phase. But so many foods are either low or high depending on their portion size. To complicate matters, there is the question of the FODMAP load in a single meal or snack. Most importantly, every person reacts to different foods and they will end up eating a modified FODMAP diet that is unique for them. This stresses the importance of securing the help of a registered dietitian who is knowledgeable in this topic to help navigate all its complexities.

3.     It’s a gluten-free diet

It is not, as gluten is not a FODMAP. FODMAPs are carbohydrates and gluten is a protein. However, gluten and a certain class of FODMAPs (fructans) coexist in wheat, barley, and rye. This is where the confusion comes. Wheat, barley, and rye and products made with these grains are excluded during the first phase of the diet to eliminate the fructans. In fact, some low FODMAP foods that contain gluten, such as soy sauce, are included. On the other hand, not all gluten-free products are low FODMAP. Many gluten-free breads and other baked products often contain high-FODMAP ingredients such as honey, agave, pear or apple juice, or inulin/chicory, which makes them not suited for a low FODMAP diet.

4.     It’s a lactose-free diet

Lactose is a FODMAP but the diet only needs to be low in lactose, not completely free of lactose. Lactose-free dairy products (milk, yogurt, cream cheese and ice cream) can be included. And so can those with minimal lactose content, for example hard cheeses like parmesan or cheddar, butter, and small amounts of cream and half-and-half.

5.     It’s a low-fiber diet

Finally, some people think they need to avoid all high-fiber foods. This is not true and can be counterproductive for those suffering of constipation. Depending on which kind of motility issue you may have (diarrhea or constipation), the fiber content will need to be adjusted and the type of fiber individualized (more soluble or insoluble fiber). Low FODMAP sources of fiber such as permitted amounts of chickpeas and lentils, low FODMAP vegetables and fruits, and low FODMAP whole grains (quinoa, brown rice, millet, oats, etc.) can and should be included. See my article 5 Tips to Eat More Fiber on a Low FODMAP Diet for more ideas.

3 Tips for Eating a Balanced Vegetarian or Vegan Low FODMAP Diet

FODMAPs are sugars and fibers that are either poorly absorbed or not absorbed at all. A low FODMAP therefore diet restricts the intake of carbohydrate-rich foods such as some grains, legumes, lactose-containing dairy, vegetables and fruits. When you add another restriction – that of a vegetarian or vegan diet, you might even wonder whether there is anything left to eat at all!

With some planning, and the help of a registered dietitian knowledgeable about FODMAPs, vegetarians and even vegans can follow a low FODMAP protocol and eat a balanced diet. As many foods are either eliminated or limited in portion sizes, vegetarians and vegans need to be especially careful in planning meals so to avoid deficiencies in protein, calcium, iron, vitamin B12 and, possibly, fiber.

Here are 3 tips to eat a balanced vegetarian or vegan low FODMAP diet.

1. Don’t skip the protein

Vegetarians are less at risk of eating too little protein as the low FODMAP diet includes eggs, lactose-free dairy products and a few types of cheeses. Vegans need to pay more attention. Each meal should include a low FODMAP source of protein such as legumes (canned lentils or chickpeas), tofu (firm, extra firm), edamame, or tempeh. I recently wrote My Guide to Eating Soy Foods on a low FODMAP Diet (including an Indonesian Tempeh recipe).

Among the low FODMAP grains, quinoa (and quinoa-based pasta), millet and oats are also high in protein - more than rice - and can contribute to the overall protein intake. According to vegetarian nutrition experts, vegetarians and vegans should aim to eat a little more protein than omnivores: about 1 g/kg body weight (instead of the general recommendation of 0.8 g/kg).

2. Include good sources of calcium

Calcium intake may be an issue for everyone on a low FODMAP diet due to the restriction of lactose. Vegetarians who like dairy products can eat lactose-free milk, yogurt, and a few kinds of hard cheeses. Vegans miss out on this food group entirely but can still meet their calcium needs by drinking calcium-fortified almond or hemp milk, and eating calcium-set tofu, and calcium-rich vegetables (bok choy and kale) and chia seeds. See more ideas in my article, 5 Tips to Eat Enough Calcium (including two tasty calcium-rich recipes).

3. Pump Up the Iron

A common pitfall for all vegetarians/vegans (whether on a low FODMAP diet or not) is eating too little iron. The best sources are, after all, red meat and organ meats. Breakfast cereals are fortified with iron but most of them are high in FODMAPs. Even so, careful meal planning can help you eat enough or close to enough. All the plant-based protein sources are high in iron (and zinc): legumes, soy products, nuts and seeds. The grains mentioned above are also rich in iron, as well as certain low FODMAP vegetables such as kale, chard, raw spinach, bok choy, and broccoli. 

You may have heard that the iron from plant foods is not as well as absorbed as the one from animal foods. However, adding a vitamin C-rich fruit or vegetable (for example, kiwi, strawberries, oranges, or red bell peppers and broccoli) at the same meal greatly increases the absorption of iron. Another useful tip is to avoid drinking coffee, tea, mint tea or cocoa with meals as the flavonoids or phenolic acid in these beverages bind the iron and reduce its absorption by as much as 50-90%. Finally, it would be best to eat calcium-rich and iron-rich foods in separate meals, as calcium and iron inhibit each other’s absorption. You need not worry about the foods that contain both (such as tofu or legumes). Mostly try not to drink lactose-free milk or almond milk with your lunch or dinner, and have those very high-calcium foods with breakfast and/or snacks.

Final Food for Thought…

A paper published by Monash University earlier this year found some popular vegan foods to have either a low or negligible FODMAP content: soy cheese, coconut yogurt, pea protein isolate, kelp noodles, vegan egg replacer, nutritional yeast, agar-agar, dulse, and spirulina. Check out the Monash University FODMAP Diet App for appropriate serving sizes.

Even when doing all things right, you may still be deficient in certain of these nutrients or may simply not be eating enough. It’s best to consult with a registered dietitian trained on the low FODMAP diet to see whether you may need to tweak your meals further or need a supplement (for example, B12 for vegans). Finally, don’t forget that the low FODMAP diet is a temporary diet and, once you have completed the re-challenge phase, you may be able to include many more foods, such as more varieties of beans and lentils, perhaps soy milk, and more choices or higher portions of vegetables.


4 Ingredients to Lower Cholesterol: The Portfolio Diet and How to Adapt It to a Low FODMAP Diet

I was sitting in the last row of a crowded shuttle bus that was taking me from my hotel to Loma Linda University, where I was attending the International Congress on Vegetarian Nutrition, when I noticed I was elbow-to-elbow with one of my nutrition research heroes: Dr. David Jenkins. I couldn’t believe it! My colleague and friend sitting next to me still remembers how excited I was – and teases me about it.

That day Dr. Jenkins would speak about the results of his recently published research on a new dietary approach that lowered blood cholesterol as much as a statin (cholesterol-lowering) drug: the Portfolio Diet. What are the highlights of this research?

  • This diet put together all the foods that, individually, had shown to lower LDL cholesterol in previous research into a “package” named the Portfolio Diet (vegetarian)

  • In the first study, research participants on the Portfolio Diet arm were fed all their food for 4 weeks

  • The average LDL (bad) cholesterol in this group decreased by 29%

  • This change was similar to that observed in the comparison group: participants took a statin drug while eating a low saturated fat diet and dropped their LDL by 31%

  • In a follow-up study, participants did not get their food but were taught the Portfolio Diet and the drop in LDL cholesterol was not as dramatic but still clinically significant (13-14%).

  • In this study, there was a range of response: the better the participants were able to stick to the diet, the bigger their cholesterol reduction (about 20%).

This was not a prisoners’ diet, but a palatable vegetarian diet: the participants liked it and felt it kept them full.  So, what does it look like? It has 4 main ingredients:

  1. Soy-based foods such as soy milk, tofu, and soy-based meat alternatives (instead of meat, poultry or dairy)

  2. Soluble fiber from grains like oats and barley, beans/lentils, certain vegetables (eggplant, okra, Brussels sprouts), and a daily serving of psyllium fiber

  3. Plant sterols as enriched margarine, fortified orange juice or yogurt, or taken in capsule form as a supplement

  4. Nuts. The research studies used almonds but other tree nuts can be substituted.

How much you need to eat of each of these components depends on your daily caloric intake. A registered dietitian can help you figure out how many grams of soy proteins, soluble fiber, plant sterols and nuts you need per day, and translate these into real foods and menu ideas.

If you are following a low or modified FODMAP diet, this plan can be easily fitted into your diet. First, I would advise you to complete the elimination and re-challenge phases of the diet. For starters, it is best to focus on one goal at a time, and first alleviate your IBS symptoms, then tackle the high cholesterol issue. The low FODMAP diet is very challenging to learn and you might be overwhelmed by having to change too many aspects of your diet at once.

Second, you will be in a much more relaxed state of mind, feel better, and be ready for a new challenge, once your symptoms have subsided. And finally, you will know which high FODMAP foods you can tolerate and expand the variety of foods you can eat. For example, you will be able to eat larger servings of okra, Brussels sprouts and beans/lentils if you have passed the oligo-saccharide challenge. If this is a problematic FODMAP category for you, you can focus on lower FODMAP sources of soluble fiber like oats, chia seeds, small servings of broccoli and sweet potato, and psyllium fiber.

Whether you have IBS or not, make sure you talk to your doctor if you decide to try this diet. This may not replace the need for medication for everyone but be a complementary therapy and perhaps allow you to lower the dosage of medications, if you are already taking them. Also, your doctor might know (or remember) about the Portfolio Diet. When I told my doctor how I was able to replicate the results of this research and she could see the 35% drop in LDL (bad) cholesterol in my new lab test results, she asked: do you mind if I use this with my patients? Of course, I answered: please, do!