7 things to know about gluten on a keto or low-carb diet

Should you worry about gluten? That’s a question many people have asked themselves over the years.

Aside from the serious medical condition called celiac disease, gluten sensitivity — also called non-celiac gluten sensitivity — was an unknown phenomenon just a few decades ago. But now evidence shows approximately 10% of the population may have abnormal reactions to this nutrient.1

Is this because the consumption of gluten-containing foods has increased? Is it because gluten has changed? Or could it be that the sensitivity is to other food substances and not gluten?

This guide will examine these questions and address what gluten is, its effects on our health, and whether we should avoid it.


1. What is gluten?

Gluten proteins, such as gliadin and glutenin, are found in grains such as wheat, barley, and rye. Gluten does not provide any essential nutrients for the body if sufficient amounts of protein are consumed from other sources.

Gluten is a “flexible” protein and can be manipulated easily. So, although it’s a natural part of some grains, gluten is now frequently added to packaged and processed foods to enhance texture and flavor. It also enables dough to rise and helps to bind foods together. Think pizza dough.

In some people, gluten is not properly digested in the digestive tract, which allows intact chains of amino acids to enter their circulation. This is one proposed reason for gluten sensitivity.2


2. What foods contain gluten?

Gluten is commonly found in carbohydrate-rich foods such as bread, baked goods, crackers, pasta, cereals, and most processed and packaged foods.

Although oats don’t contain gluten, most commercial oats are cross-contaminated with gluten from contact with other grains during harvesting and processing. This can include oat fiber, an ingredient used in some low-carb recipes.

Other foods that may surprisingly contain gluten are some soups, commercially-prepared bouillon and broths, cold cuts, processed cheese (e.g., Velveeta), mayonnaise, soy sauce, salad dressings, and sausage.

Gluten-free alternatives for most of these products are available. If you have a gluten sensitivity, make sure to check the labels when purchasing these types of products.


3. What are the different types of conditions associated with gluten intolerance?

There is a spectrum of known gluten-related conditions ranging from wheat allergy to celiac disease, all related to an immune response to gluten.

Celiac disease

The most severe type of gluten disorder is known as celiac disease. Studies suggest this condition affects less than 1% of the population, although some believe it is more common.3

Celiac disease is an autoimmune response to gluten where immune cells start to attack other cells or tissues of the body. This can lead to inflammation, damage to the lining of the intestine, and a reduced ability to absorb nutrients.4

The onset of symptoms is usually gradual and may take months or years to develop after the introduction of gluten. These include digestive upset such as diarrhea, gas, bloating, fatigue, and weight loss. Celiac disease may also be associated with other conditions such as osteoporosis and iron-deficiency anemia due to the lack of nutrient absorption.

Certain individuals with a genetic predisposition are at increased risk of developing celiac disease, but only a small percentage actually develop it. There may be other environmental triggers in addition to genetics and exposure to gluten, but the exact sources have not been identified.

Wheat allergy

Wheat allergy is one of the most common food allergies, estimated to effect around 1% of pediatric populations.5 Symptoms are those typically associated with a food allergy, such as swelling, rash, nausea or vomiting and diarrhea. Much less common are difficulty breathing or anaphylaxis.6

Non-celiac gluten sensitivity

Non-celiac gluten sensitivity is the milder form of gluten intolerance that occurs due to an immune response to gluten.

It is likely the most common of the gluten-related disorders, estimated at around 6% of the population.7 The onset of symptoms usually occurs hours to days after gluten exposure. These symptoms may include digestive distress. In addition, studies have shown it can lead to an overall reduction in quality of life measures.8

It’s often hard to differentiate non-celiac gluten sensitivity from other gastrointestinal conditions such as wheat allergy and irritable bowel syndrome, as there is no test to diagnose this type of gluten sensitivity.

Therefore, diagnosis is made by exclusion of other gluten-related or gastrointestinal disorders. In most people, symptoms disappear after removing gluten from the diet for a few weeks, with little to no lasting effects.

Treatment

The only available treatment for gluten-related conditions is a gluten-free diet, as the offending nutrient causing harm needs to be removed.


4. Why does gluten get such a bad rap?

Gluten continues to be demonized by many health-conscious individuals. But does it deserve this reputation?

For those with celiac disease, gluten definitely deserves the bad rap. These individuals have an autoimmune reaction to gluten that can cause many health troubles, as discussed above.

The science tells us that certain components of gluten cannot be broken down by enzymes in the digestive tract.9As a result, in some genetically-susceptible people, exposure to gluten can trigger an allergy or an immune response.

But is gluten “bad” for those without celiac disease?

Gluten has been directly or indirectly implicated in the development of an array of health conditions such as irritable bowel syndrome, inflammatory bowel disease, anemia, fatigue, depression, headaches, and more.10

Although it is unlikely that gluten causes these conditions, gluten sensitivity could potentially worsen them.

There is increasing speculation that changes to gluten in food processing or the increase in gluten intake may be responsible for the rising prevalence of gluten-related conditions. In addition, it’s not always clear if symptoms are from gluten itself or from gluten-containing refined carbohydrate foods.

In these cases, gluten may or may not be the offending agent. Fortunately, there are ways to investigate whether gluten is the issue.


5. How do I know if I have an issue with gluten?

Most people with gluten intolerance will experience adverse symptoms relating to the skin, digestive system, or respiratory system.

Of course, not all skin, digestive or respiratory symptoms are due to gluten exposure. Therefore, removing and then reintroducing gluten from the diet may be a good first step in identifying gluten sensitivity. You can also talk to your healthcare provider about blood tests that may help diagnose a gluten intolerance issue.

However, it is often difficult to diagnose the exact type of intolerance or to pinpoint if it’s related specifically to gluten or some other component in carbohydrate-containing foods. A series of different food tolerance tests may be your best bet.

For instance, if you do just fine with gluten-containing homemade bread but have symptoms after eating processed gluten-containing products from the store, the main offender may not be gluten. But if you react poorly to both of these, then there is a higher likelihood that gluten could be the problem.


6. Should I avoid gluten or eat gluten-free foods even if I am not intolerant?

The trend of individuals reducing or eliminating gluten from their diets is increasing worldwide.11

Although a gluten-free diet is a necessity for people with gluten intolerance, people without diagnosed gluten issues are also excluding it from their diets for weight loss or overall health improvements. Most of the evidence in these cases is anecdotal, and many people claim to experience improvements in health when removing gluten-containing foods from their diets.

Gluten free does not necessarily mean healthier

Despite the health claims for eating gluten-free, no scientific evidence supports weight loss with a gluten-free diet or suggests that the general population would benefit from avoiding gluten for health reasons.12

In addition, many people think that a gluten-free diet is healthier and more nutritious, but the opposite may actually be true in some cases as many of these diets contain highly processed foods.

Gluten-free diets, especially those high in processed foods and refined carbohydrates, can be deficient in important nutrients such as iron, zinc, vitamin D, and protein.

Foods labeled as gluten-free are often made with refined grains and additives such as tapioca starch, less commonly fortified with folic acid and iron, and have less fiber and more sugar compared to regular gluten-containing foods.13

Several studies have actually found a tendency toward weight gain and obesity among those who follow a gluten-free diet.14

We suspect these findings would be significantly different for a whole-foods, minimally processed gluten-free diet.

Is it the gluten or something else that may be adversely affecting our health?

Symptoms related to gluten intolerance often mimic those of other food sensitivities such as intolerances to FODMAPs (fermentable, oligosaccharides, disaccharides, monosaccharides and polyols), lactose, fructose, or carbohydrates. Or the symptoms may mimic other conditions such as inflammatory bowel disease and irritable bowel syndrome.15

Bottom line

The bottom line is that since we don’t need gluten, there’s likely no harm in avoiding it. And if you think you are sensitive to it, you can always consider removing it from your diet to see if symptoms improve.

But in the end, we may not know if it is more about eliminating gluten-containing foods rather than the gluten itself.

As with any diet, when eliminating certain foods or nutrients, you still have to pay attention to what replaces it. Eating processed gluten-free food is not automatically healthier than a potentially less processed gluten-containing version.


7. Gluten and low-carb or ketogenic diets

Since gluten is most commonly found in carbohydrate-containing foods, low-carb and ketogenic diets are almost always low in gluten. A keto diet, in particular, is usually gluten-free because foods containing gluten have too many carbs to fit within the diet.

However, you may find that some low-carb and keto foods contain a small amount of gluten, especially jerky, sausages, soups and broths. If you have a gluten sensitivity, you may want to consider less processed or gluten-free versions.16

The bottom line is that a low-carb or ketogenic diet is a great alternative for individuals with gluten or other carbohydrate-related intolerances. Plus, you may see numerous other potential benefits from carbohydrate reduction such as weight loss, improved metabolic health, and more.

You can read more about those benefits in our evidence-based guides on low-carb and keto diets.

More

  1. BMC Medicine 2012: Spectrum of gluten-related disorders: Consensus on new nomenclature and classification [overview article; ungraded]

  2. Molecular Metabolism 2017: The human digestive tract has proteases capable of gluten hydrolysis [nonrandomized study, weak evidence]

  3. Clinics in Gastroenterology and Hepatology 2018: Global prevalence of celiac disease: systematic review and meta-analysis [observational study, weak evidence]

  4. World Journal of Gastrointestinal Pathophysiology 2017: Celiac disease: From pathophysiology to treatment [overview article; ungraded]

    BMC Medicine 2019: Celiac disease: a comprehensive current review [overview article; ungraded]

  5. Journal of Asthma and Allergy 2016: Wheat allergy: diagnosis and management [overview article; ungraded]

  6. Clinical & Experimental Gastroenterology 2014: US perspective on gluten-related diseases [overview article; ungraded]

  7. As the following studies show, the estimated range is inexact and suffers from differences in definition and whether the study was self reported or an RCT.

    The following study found a prevalence of 16%, but also noted a nocebo effect of 40%. Thus the more likely number is closer to 6% (16X40%=6.4)

    Clinics in Gastroenterology and Hepatology 2017: Suspected nonceliac gluten sensitivity confirmed in few patients after gluten challenge in double-blind, placebo-controlled trials [systematic review of randomized trials; strong evidence]

    The following was a study of self reported incidence and also found it to be close to 6%.

    Nutrients 2016: Prevalence and characterization of self-reported gluten sensitivity in the Netherlands [self-reported study, weak evidence]

  8. Nutrients 2016: Evidence for the presence of non-celiac gluten sensitivity in patients with functional gastrointestinal symptoms: results from a multicenter randomized double-blind placebo-controlled gluten challenge [randomized trial; moderate evidence]

    BMC Medicine 2012: Spectrum of gluten-related disorders: Consensus on new nomenclature and classification [overview article; ungraded]

    Clinical & Experimental Gastroenterology 2014: US perspective on gluten-related diseases [overview article; ungraded]

  9. Nutrients 2016: Properties of gluten intolerance: gluten structure, evolution, pathogenicity and detoxification capabilities [overview article; ungraded]

  10. The following studies suggest an association with these conditions, but as with much of nutritional science, this does not clearly point to a cause and effect relationship. That would require much more detailed, controlled longer-term studies.

    Current Treatment Options in Neurology 2019: Treatment of neurological manifestations of gluten sensitivity and coeliac disease [overview article; ungraded]

    Diabetes Spectrum 2017: The gluten-free diet: Fad or necessity? [overview article; ungraded]

    Clinical & Experimental Gastroenterology 2014: US perspective on gluten-related diseases [overview article; ungraded]

    Biomed Research International 2013: Celiac disease and autoimmune-associated conditions [overview article; ungraded]

  11. European Journal of Gastroenterology and Hepatology 2014: A UK study assessing the population prevalence of self-reported gluten sensitivity and referral characteristics to secondary care [observational study, weak evidence]

    Journal of Nutrition & Metabolism 2019: A gluten-free diet, not an appropriate choice without a medical diagnosis [overview article; ungraded]

  12. Journal of Nutrition & Metabolism 2019: A gluten-free diet, not an appropriate choice without a medical diagnosis [overview article; ungraded]

    Nutrients 2020: Celiac disease, gluten-free diet, and metabolic and liver disorders [overview article; ungraded]

    Journal of the American Medical Association 2017: Celiac disease and nonceliac gluten sensitivity: A review [overview article; ungraded]

  13. Journal of Pediatric Gastroenterology and Nutrition 2006: Nutritional management of the gluten-free diet in young people with celiac disease in the Netherlands [observational study, weak evidence]

    Nutrients 2019:Gluten-free diet: Gaps and needs for a healthier diet [overview article; ungraded]

  14. Alimentary and Pharmacologic Therapies 2012: Body mass index and the risk of obesity in coeliac disease treated with the gluten-free diet [observational study, weak evidence]

    European Journal of Clinical Nutrition 2010 Celiac disease and obesity: Need for nutritional follow-up after diagnosis [observational study, weak evidence]

    Diabetes Spectrum 2017: The gluten-free diet: Fad or necessity? [overview article; ungraded]

    Nutrients 2020: Celiac disease, gluten-free diet, and metabolic and liver disorders [overview article; ungraded]

  15. Alimentary Pharmacology & Therapeutics 2015:Review article: The aetiology, diagnosis, mechanisms and clinical evidence for food intolerance [overview article; ungraded]

  16. At Diet Doctor, our recipes don’t use ingredients known to contain gluten because it can cause problems for people sensitive to it, even in small amounts. In spite of this, we can’t guarantee that some ingredients used in our recipes (ground psyllium husk, oat fiber and protein powder, etc.) haven’t been contaminated during production.