Lately, there has been a lot of fuss about the FODMAP diet, and it is easily confused with a gluten-free diet. Both of these diets are therapeutic and are aimed at alleviating the symptoms of people who have specific digestive or autoimmune disorders.
However, contrary to popular belief, a gluten-free diet is NOT the same as a FODMAP diet. Here we explain what each diet entails, why you would follow them, the advantages and disadvantage of each one.
What is a Gluten-Free Diet?
A gluten-free diet is a diet that excludes foods that have the protein gluten. Gluten is a plant protein that is found in wheat, barley, rye, and triticale among others (5).
Wheat-free foods don’t necessarily mean they are gluten free. Not only wheat contains gluten, so it is important to look for the gluten-free label, or read the ingredients carefully.
The Celiac Disease Foundation as published a list of foods to avoid if you are following a gluten-free diet:
- Varieties and derivatives of wheat such as:
- KAMUT® Khorasan wheat
- einkorn wheat
- Maltin various forms including malted barley flour, malted milk or milkshakes, malt extract, malt syrup, malt flavoring, malt vinegar
- Brewer’s Yeast
Why Would Someone Follow a Gluten-Free Diet?
The gluten-free diet was developed for people with celiac disease. According to the Celiac Disease Foundation, “Celiac disease is an autoimmune disorder that can occur in genetically predisposed people where the ingestion of gluten leads to damage in the small intestine. It is estimated to affect 1 in 100 people worldwide. Two and one-half million Americans are undiagnosed and are at risk for long-term health complications” (6).
When a person with celiac disease eats gluten, their body’s immune system attacks the small intestine, which damages the intestinal lining and can lead to poor nutrient absorption.
According to the Celiac Disease Foundation, some of the symptoms of celiac disease in adults include:
- unexplained iron-deficiency anemia
- bone or joint pain
- bone loss or osteoporosis
- depression or anxiety
- tingling numbness in the hands and feet
- seizures or migraines
- missed menstrual periods
- infertility or recurrent miscarriage
- canker sores inside the mouth
- an itchy skin rash called dermatitis herpetiformis (8)
It is also possible to have gluten sensitivity without necessarily having celiac disease. This is call non-celiac gluten sensitivity (NCGS). Unfortunately, it is a poorly understood condition and is often misunderstood and misdiagnosed. Researchers are still unsure whether it is a reaction to the gluten itself or another carbohydrate found in foods that also contain gluten (9).
The main difference between NCGS and celiac disease is that NCGS is not an autoimmune disorder and it is not inherited. No damage is caused to the intestine, but there are still many uncomfortable symptoms that present themselves after having eating gluten-containing foods, including:
- mental fatigue
- lack of energy or lethargy
- abdominal pain or cramps
Unfortunately, there is no test that can determine NCGS. After ruling out celiac disease and a wheat allergy, NCGS might be diagnosed by exclusion. It is very important that, if you suspect having an adverse reaction to gluten, to get tested for wheat allergy and celiac disease before initiating a gluten-free diet (9).
What are the Advantages of a Gluten-Free Diet?
If you have celiac disease, a wheat allergy, or a non-celiac gluten sensitivity, a gluten-free diet might be able to alleviate your symptoms completely. You will feel less bloated, not experience diarrhea or constipation as a result of the disorders, and function better on a daily basis. Most importantly, you will be protecting your gut health and longevity through ensuring you are getting the right nutrients in your body.
What are the Disadvantages of a Gluten-Free Diet?
A gluten-free diet is not easy to follow. This is especially true in North America where gluten-containing foods are very common.
Because gluten-free diets restrict many common foods, it is also important to get guidance from a registered dietician in order to make the best food choices and avoid falling into nutrient deficiencies.
Another disadvantage is the many people with celiac disease or non-celiac gluten sensitivity doesn’t find symptoms relief even after following a strict gluten-free diet. If this is the case, it might be important to take the next step and talk to your registered dietician about starting a FODMAP diet, explained below.
The FODMAP Diet
What are FODMAPs?
Unfortunately, FODMAP doesn’t stand for anything too easy to remember. FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. All of these elements are commonly found in many foods, and they share small chain sugars and fibers that some people may have trouble digesting, resulting in gas, stomach aches, bloating and diarrhea (1).
Oligosaccharides are a carbohydrate that is poorly absorbed, and is found in:
- beans, peas and pulses
- foods in the onion family
- certain food additives like inulin and fructooligosaccharides (2).
Disaccharides are carbohydrates found in milk, particularly lactose. Many populations that aren’t of European descent absorb these very poorly. And should avoid milk and milk products or limit intake to 50 milliliters (2).
Fructose is the main monosaccharide that should be avoided when following an FODMAP Diet. Fructose is a carbohydrate found in fruits and honey. While limited amounts are okay, too much can cause glucose problems. This include:
- fructose (as an additive)
Polyols are sugar alcohols that are often added to sugar-free foods in order to lower the calories without sacrificing taste. When added you can often find them on the label as sorbitol and xylitol. They are also found naturally in some foods like:
Why Would Someone Follow the FODMAP Diet?
The FODMAP diet was developed by Dr. Sue Shepherd, who is a dietitian and nutritionist. She estimates that about 20% of the population in the US suffers from chronic digestive illnesses (1).
The FODMAP diet has been found to be particularly helpful for people suffering from IBS. According to NHS Choices of the UK, the typical symptoms of IBS include:
- abdominal (stomach) pain and cramping, which may be relieved by having a poo
- a change in your bowel habits – such as diarrhea, constipation, or sometimes both
- bloating and swelling of your stomach
- excessive wind (flatulence)
- occasionally experiencing an urgent need to go to the toilet
- a feeling that you have not fully emptied your bowels after going to the toilet
- passing mucus from your bottom
If you feel like you might have IBS, it is important to talk to a health professional before self-diagnosing and following a restrictive diet, such as FODMAP, without guidance (3).
What are the Advantages of a FODMAP Diet?
People who have debilitating symptoms of IBS may benefit greatly from following the FODMAP diet. The uncomfortable symptoms of bloating, gas, diarrhea or constipation often disappear after several days or weeks of following the FODMAP diet.
It is also beneficial for people with celiac disease and non-celiac gluten sensitivity that don’t find relief following only a gluten-free diet.
What are the Disadvantages of a FODMAP Diet?
The FODMAP diet limits many foods (even some you wouldn’t think would have a negative effect on your bowel) and if you don’t have the right nutritional assessment, it is easy to have nutrient deficiencies. IBSdiets.org published a list of foods you should limit following the FODMAP Diet (4):
|Vegetables and Legumes||Fruit – fruits can contain high fructose|
|Garlic – avoid entirely if possible||Apples|
|Onions – avoid entirely if possible||Apricots|
|Black eyed peas||Custard apple|
|Celery – greater than 5cm of stalk||Grapefruit|
|Haricot beans||Paw paw, dried|
|Mange Tout||Pineapple, dried|
|Peas, sugar snap||Pomegranate|
|Red kidney beans||Prunes|
|Soybeans / soya beans||Sultanas|
|Scallions / spring onions (bulb / white part)||Tinned fruit in apple / pear juice|
|Cereals, Grains, Bread, Biscuits, Pasta, Nuts and Cakes||Meats, Poultry and Meat Substitutes|
|Products with wheat:||Chorizo|
|Biscuits including chocolate chip biscuits||Sausages|
|Bread, wheat – over 1 slice||Processed meat – check ingredients|
|Cereal bar, wheat based|
|Croissants||Beer – if drinking more than one bottle|
|Egg noodles||Cordial, apple, and raspberry with 50-100% real juice|
|Muffins||Cordial, orange with 25-50% real juice|
|Pasta, wheat over 1/2 cup cooked||Fruit and herbal teas with apple added|
|Udon noodles||Fruit juices in large quantities|
|Wheat bran||Fruit juices made of apple, pear, mango|
|Wheat cereals||Orange juice in quantities over 100ml|
|Wheat noodles||Sodas containing High Fructose Corn Syrup (HFCS)|
|Wheat rolls||Soy milk made with soy beans – commonly found in the USA|
|Almond meal||Tea, black with added soy milk|
|Amaranth flour||Tea, chai, strong|
|Barley including flour||Tea, dandelion, strong|
|Bran cereals||Tea, fennel|
|Bread, multigrain||Tea, chamomile|
|Bread, naan, roti||Tea, herbal, strong|
|Bread, oatmeal||Tea, oolong|
|Bread, pumpernickel||Wine – if drinking more than one glass|
|Bread, sourdough with kamut|
|Cashews||Condiments, Dips, Sweets, Sweeteners, and Spreads|
|Einkorn flour||Caviar dip|
|Granola bar, wheat bread||Gravy, if it contains onion|
|Muesli cereal||High fructose corn syrup (HFCS)|
|Muesli bar||Hummus / houmous|
|Rye||Jam mixed berries|
|Rye crispbread||Jam, strawberry, if contains HFCS|
|Spelled flour||Quince paste|
|Relish / vegetable pickle|
Main Differences Between Gluten-Free and FODMAP Diets
People who have symptoms of IBS often first follow gluten-free diets and see some improvement. However, the FODMAP Diet is based on extensive research that shows that it isn’t necessarily gluten per se, rather specific carbohydrates that trigger the most uncomfortable symptoms of IBS (1). In some people who suffer from IBS, a gluten-free diet may not be enough.
Some people who have IBS and non-celiac gluten sensitivity may see improvement in their digestive symptoms after following the gluten-free diet. This is because restricting gluten also restricts many of the foods that contain FODMAPS (like wheat, barley, and rye), but not all of them (1).
Additionally, 20% of people with celiac disease that follow a gluten free diet continue to have some symptoms, similar to those who have IBS. Slightly more people with non-celiac gluten sensitivity don’t feel complete relief with a gluten-free diet. In these cases, a FODMAP diet might be the next recourse (7).
The main difference between FODMAP and gluten-free diets is that gluten-free is focused specifically on grains that contain the protein called gluten. FODMAPS target a range of carbohydrates found in many food groups, which, unlike the gluten-free diet, target fruits, vegetables, legumes, and dairy as well.
While many gluten-containing foods also contain FODMAPS, many foods not allowed in the FODMAP diet are allowed on the gluten-free diet. In short, the FODMAP diet is much more restrictive than the gluten-free diet.
As mentioned previously, both of these diets restrict the intake an important food group that tends to be an important element of our food culture. That is why it is important to seek out the guidance of a professional before taking on either of these diets to ensure that you do not have nutrient deficiencies as a result of improper food choices.