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Going gluten-free? Things to consider, part 2: Fiber

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Earlier this week, I started a series of posts about what people should consider when they embark on a gluten-free diet for reasons other than celiac disease, such to alleviate symptoms of a gluten sensitivity.

My first post was on folate, an important B vitamin that appears to be less prevalent in gluten-free grain products when compared to their gluten-containing counterparts.

Another important nutrient that can be harder to get on a gluten-free diet is fiber.

Fiber is one of three main types of carbohydrates, the other two types being starch and sugar. Fiber is present naturally in plants, but unlike starch and sugar, this carbohydrate is not digested as it passes through our system [2]. In the diet, it typically comes from fruits, vegetables, nuts and whole grains [2].

Not digestible doesn’t mean not important though; the Dietary Guidelines for Americans classify it as a nutrient that needs to be increased in the American diet. The current guidelines suggest 25 grams of fiber per day for women and 38 grams per day for men – and note that the average person gets only 15 grams per day.

The reasons? The guidelines cite fiber’s role in a healthy digestive system and note that it may help reduce the risk of diseases like obesity, type 2 diabetes and cardiovascular disease. Fiber may also play a role in reducing colorectal cancer risk, though evidence is not conclusive [2]. Other components of high fiber foods may be providing the benefits, so the American Cancer Society recommends a diet made up of a variety of high-fiber foods, such as whole grains.

Without the ability to eat some of these whole grains, such as wheat, do gluten-free eaters get enough fiber?

A search of the literature turned up only a few studies on fiber and the gluten-free diet. In addition, these studies only looked at people following a strict gluten-free diet due to celiac disease, so fiber intake could differ for people choosing gluten-free diets for other reasons.

A small 2005 study in the Journal of Human Nutrition and Dietetics surveyed 47 people with celiac disease on a gluten-free diet. The study found the majority of males consumed enough fiber, while over half of the females did not, based upon a 2002 American Dietetic Association recommendation of 20-35 grams per day for healthy adults. Interestingly, though the participants consumed less fiber than recommended, they consumed more fiber than participants from a study geared at the general population – the U.S. National Health and Nutrition Examination Survey. The small size of the study may have limited the accuracy of it’s results, however. A slightly larger study looked at the gluten-free diets of 137 people with celiac disease in the United Kingdom. Women in this study had lower intakes of fiber compared to a study of women with a variety of dietary patterns– the United Kingdom Women’s Cohort Study.

Why might the gluten-free diet be low in fiber? The American study cites one of the other three carbohydrates, starch, as a possible reason. As I mentioned in my folate blog, many gluten-free versions of foods, such as breads or muffins, replace gluten-containing grains with starch. These starches – such as rice, corn, tapioca or potato starch – contain little to no fiber [3].

So while following a gluten-free diet doesn’t necessarily lead to a low fiber intake, it’s worth thinking about how you will get enough of this nutrient, if you’re planning to go gluten-free.

Fiber can be found in whole grains that don’t contain gluten, including quinoa, buckwheat, teff, millet, amarath, and brown rice. (Check out this Mayo Clinic article that shows you how to cook them and add them to your diet). For example, a cup of cooked quinoa contains about 5.2 grams of fiber. That’s about the same as the amount of fiber in 2 and a half slices of whole wheat bread. A cup of cooked brown rice contains less, around 3.5 grams of fiber, but might be easier to find then some of the more unusual gluten-free grains. Other high-fiber foods include beans or peas, which range from 5 to 9 grams of fiber per serving (1/2 cup), depending on the type[1].


  1. U.S. Department of Agriculture and U.S. Department of Health and Human Services. (2010). Dietary Guidelines for Americans, 2010. Washington, DC: U.S. Government Printing Of€fice. Retrieved from
  2. The American Cancer Society 2010 Nutrition and Physical Activity Guidelines Advisory Committee (2012). American Cancer Society guidelines on nutrition and physical activity for cancer prevention. CA: A Cancer Journal for Clinicians, 62 (1). doi: 10.3322/caac.20140 Retrieved from
  3. Thompson, T. Folate, iron, and dietary fiber contents of the gluten-free diet. Journal of the American Dietetic Association.100(11). Retrieved from
Julianne Wyrick About the Author: Julianne Wyrick has a bachelor’s in biochemistry and is currently a master’s student in the health and medical journalism program at the University of Georgia, where she also writes about science for the Office of Research Communications. Find her on the web at Follow on Twitter @juliannewyrick.

The views expressed are those of the author and are not necessarily those of Scientific American.

Comments 6 Comments

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  1. 1. dbtinc 8:32 am 12/1/2013

    Just curious… In the US what is the frequency of celiac disease or gluten sensitivity? This gluten-free rage is just that, a temporary phenomenon hyped by the food marketing guys to convince us of something we don’t need.

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  2. 2. lamorpa 10:26 am 12/1/2013

    My 15 years of ever increasing joint pain switched off almost completely after 4 days of being gluten free and has improved since. It’s real for some people. Certainly not worth the trouble just for the heck of it, but for me it was a life changer.

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  3. 3. bakrantz 1:26 pm 12/1/2013

    Obviously the newer trend may appear on its face to be a scheme or whatever you imply, but if you look into the issues and speak to the people affected by the gluten protein, you will find much pain and discomfort is averted for the population that is sensitive to the protein. I cannot cite any studies, because their obviously has not been enough time to conduct multidecade studies on the issue.

    But I will offer my personal fight with the problem over multiple decades. I am about 4o years old. When I entered my undergraduate school I started the undergraduate diet, high in pizza, pasta and bread. About that time I developed what I know in retrospect was irritable bowel disease (IBD) going to the bathroom about 3-4 times daily, when the average is 0-1 daily. I did not know why this was the case but I did visit physicians who only prescribe antibiotics. These apparently exacerbate the issue by destroying your gut flora. Over the next several years I developed extreme skin rashes now in retrospect that coincide with herpetiformis dermatitis. These are red bumps on the elbows, knees, knuckles and space between the butt and upper leg. The dermatologist did not think logically that this was a 60-70% risk factor for gluten reaction and gave topical steroid creams instead.

    I then preceded to experience extreme diarrhea and abdominal pain and gas over the next several years. Multiple visits to the doctors again led to more antibiotics and no real relief from the pain. Joint pain began to develop over the next 3-4 years. The skin rashes do not go away really and they are seasonal. Some thought is that vitamin D can suppress the skin problem but this is seasonal and by the late Fall the skin problems come but fiercely.

    Then the fun began with the nutrient depletions. The basic problem is that gluten inflames your gut to the point you have limited ability to absorb food and nutrients, like fat soluble vitamins and B vitamins. The major problems associated with these deficiencies are neurological. You begin to lose the ability to focus. You can become paranoid and so forth. You can lose your temper easily. It is not fun.

    Fortunately, I discovered purely on my own with no help from a trained physician that I needed to stop eating gluten. The story there was that giant red bumps developed on a hike in the woods where grass seed embedded into my skin. I looked up the rash and the symptoms of gluten reactions and realized what it was that was afflicting my all these years.

    So yes it may seem exaggerate to you personally, but those of us that are being spared the agony appreciate the Public Service Message and the few profiteers. It is worth it and quite a physical relief. I hope that helps you understand.

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  4. 4. vapur 2:52 pm 12/2/2013

    This problem, Vitamin B and Folate deficiency, could easily be solved if people introduced Dandelion into their diet. It seems to me that we are trying to reinforce society to eat only Monsanto-approved bread, and that labels like gluten-free should be more expensive by mere suggestion.

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  5. 5. E.Nordman 1:12 am 12/3/2013

    The level of Celiac disease in the US is about 1/133. It doesn’t vary much around the world. Almost all the people in the US who have Celiac don’t know they have it. In a few countries they test all students. Why anyone would go on a gluten free diet if they don’t need to is beyond me.

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  6. 6. rock johny 11:32 am 05/20/2014

    So what happened to Part 1 of this? Link no longer works. Did it contain some bad info?

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