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No Link Between Gluten and Brain Health

Misguided dieters may avoid gluten for fear of “grain brain,” and yet research suggests that these fears are unfounded. In a study of 13,494 women without celiac disease, there was absolutely no relationship between gluten and cognitive function. The authors confirm that “restricting dietary gluten for the purpose of maintaining or improving cognition is not warranted in the absence of celiac disease or established gluten sensitivity.”
JAMA Network Open. 2021 May 3;4(5):e2113020. doi: 10.1001/jamanetworkopen.2021.13020. (Wang Y et al.)

Unsubstantiated Health Beliefs Lead People to Avoid Gluten Unnecessarily

Following a gluten-free diet is required for those with celiac disease or medically diagnosed gluten sensitivities. Because gluten-free foods tend to be less nutritious and may raise the risk of nutrient deficiencies, researchers wanted to know what motivates people to avoid gluten when it is not medically necessary. In this study, 2,982 adults in the US without celiac disease were surveyed about their beliefs regarding gluten-free diets. Compared with people who eat gluten, people without celiac disease who avoid gluten are more likely to believe medically unsubstantiated claims (that gluten-free diets are more nutritious and can improve acne).  
Appetite. 2021 Jan 1; 156:104958. doi: 10.1016/j.appet.2020.104958 (Arslain K et al.)

Modern Wheat Does NOT Have More Gluten than Ancient Wheat

Over the past centuries, the yield production of wheat has dramatically increased around the globe, leaving some to wonder how the quality and gluten content of modern wheat compares to ancient varieties. This research analyzed more than 200 wheat lines from the 18th century through modern times. The results showed that modern breeds of wheat tend to have slightly higher starch and fiber levels, and lower protein content as well as lower levels of some minerals (iron, zinc, magnesium). In fact, the decreased gliadin: glutenin ratio in modern wheat indicates a decrease in celiac disease antigens in modern wheat, while the lower protein content indicates lower levels of gluten.
Nutrition Bulletin. 2020 Sept. doi:10.1111/nbu.12461. (Shewry PR et al.)

 

Kids with Celiac Disease Tend to Eat Less Fiber, More Saturated Fat on Gluten-Free Diet

Lifelong adherence to a gluten-free diet is a medical necessity for people with celiac disease. However, extra care must be taken to ensure that a gluten-free diet is nutritionally balanced. In this study, researchers analyzed the diets of 120 children with celiac disease who had been eating a gluten-free diet for at least 2 years, along with 100 age-and-gender-matched healthy children who didn’t avoid gluten. Those on a gluten-free diet ate significantly more saturated fat (contributing to 12.8% vs 8.8% of total calories) and significantly less fiber (12.6 g vs 15 g) daily than those not on a gluten-free diet.
Nutrients. 2020 Jan 4;12(1). pii: E143. doi: 10.3390/nu12010143.(Lionetti E et al.)

Going Gluten-Free Does Not Improve Digestive Symptoms in Healthy Volunteers

If you don’t have a medically-diagnosed problem with gluten, is there any benefit to going gluten-free? New research suggests not. In this study, scientists randomly assigned 28 people without medical problems with gluten to a gluten-free diet or a gluten-containing diet for 2 weeks. The gluten-containing diet did not generate any symptoms (diarrhea, reflux, constipation, fatigue, etc.) in these healthy volunteers. They concluded that because a gluten-free diet is often less healthy than a typical diet, “there is possibly clinical justification in actively discouraging people from starting it if they have no diagnosable sensitivity.”
Gastroenterology. 2019 September;157:881-883. doi: 10.1053/j.gastro.2019.05.015. (Croall ID et al.)

Gluten-Free Diet Not Appropriate without Medical Diagnosis

Gluten is a compound found naturally in wheat, barley, and rye that helps dough stretch and bread rise. Many misguided dieters today choose to go gluten-free, even though only about 1% of the population has celiac disease (an autoimmune disorder where gluten must be avoided). In this review, researchers analyzed studies on the nutritional adequacy of gluten-free diets. They found that gluten-free diets tend to have less fiber, calcium, magnesium, zinc, vitamin B12, folate, and vitamin D, and tend to have more saturated fat and exposure to arsenic. The researchers note that “the majority of persons adopting a [gluten-free diet] have no medical basis for doing so,” and that “only persons with [celiac disease], [wheat allergy], or [non celiac gluten-sensitivity] should follow a [gluten-free diet], and they should do so under medical supervision.”
Journal of Nutrition and Metabolism. 2019 Jul 1;2019:2438934. doi: 10.1155/2019/2438934. [Diez-Sampedro A et al.]

Gluten Free Kids' Foods No Healthier than Regular Kids' Foods

Many parents buy gluten-free foods for their kids because they think that those foods are healthier. But unless you have a medically-diagnosed reason to avoid gluten (such as celiac disease), evidence suggests otherwise. Researchers in Canada went to 2 major supermarket chains and purchased all foods marketed to kids (with the exception of candy, soda, and a few other “junk foods”) – 374 products total. They then analyzed the nutrition labels of the foods, to see how products marketed as gluten free stacked up to those not marketed as gluten free. For a more direct comparison, they then identified 43 gluten-free foods marketed to kids that had a non-gluten-free counterpart, and compared nutrition between the matched products. Overall, nutrition was poor among all kids’ products, gluten-free or not, and there were few significant differences. Specifically, products marketed as gluten-free had slightly lower levels of sodium, but slightly higher levels of added sugar. Additionally, a higher proportion of gluten-free products had high levels of trans fat. The researchers concluded that “[gluten-free] supermarket foods that are targeted at children are not nutritionally superior to regular child targeted foods and may be of greater potential concern because of their sugar content,” adding that “parents who substitute [gluten-free] products for their product equivalents (assuming [gluten-free] products to be healthier) are mistaken.”
Pediatrics. 2018 Aug;142(2). pii: e20180525. (Elliott C et al.)

Delayed Gluten Introduction May Be Linked with Type 1 Diabetes Risk

In a study of 8,676 babies with a genetic risk for type 1 diabetes, researchers took blood samples every 3 months for at least 9 months after birth and analyzed their diet. Every 1-month delay in gluten introduction was linked with a significantly higher risk of the immune system attacking the pancreatic cells that are important for blood sugar regulation (as measured by islet autoimmunity) as well as higher levels of insulin autoantibodies, which are predictors of type 1 diabetes. In fact, introducing gluten after 9 months was linked with a 57% higher risk of islet autoimmunity than introducing gluten between 4-9 months of age. The researchers suggest that the timing of gluten be studied further, so that healthcare providers can more confidently suggest a recommended window.
Diabetes Care. 2018 Mar;41(3):522-530. (Uusitalo U et al.)

Gluten Not Directly Responsible for Symptoms of Non-Celiac Gluten Sensitivity

Interest in a gluten-free diet has grown tremendously over the past decade. However, new research raises questions about whether gluten is a culprit of intestinal distress. In this study, researchers at the University of Oslo tested reactions to fructan (a compound found naturally in wheat and vegetables like onions, asparagus, and garlic) and gluten (a protein found naturally in wheat, barley, and rye). In a highly-controlled study of 59 people following a self-reported gluten-free diet, researchers tested patients’ symptoms after exposure to gluten, fructan, and a placebo.  Interestingly, 13 participants had significant symptoms after eating gluten, 24 had symptoms after eating fructan, and 22 had symptoms after eating a placebo, a food without gluten or fructan. There was no difference in GI symptoms after the gluten or placebo and more patients had reactions to the fructan as opposed to the gluten. The authors conclude that their findings weaken the use of the term “Non-Celiac Gluten Sensitivity,” and raise “doubts about the need for a gluten-free diet in such patients.
Gastroenterology. 2017 Nov 1. pii: S0016-5085(17)36302-3. (Skodje GI et al.)

Gluten Not Related to Heart Disease, but Avoiding Whole Grains Is

Unless you have celiac disease, you might want to rethink that gluten-free diet. In a study of more than 100,000 US adults without celiac disease, followed for more than 25 years, researchers found that eating gluten was not related to heart disease risk. In fact, the researchers caution that avoiding gluten may result in eating fewer whole grain foods, which may in turn pose a risk for heart disease.
BMJ. 2017 May 2;357:j1892. (Lebwohl B et al.)

Few Patients with Suspected Non-celiac Gluten Sensitivity Actually Show Gluten-Specific Symptoms

Many patients who respond well to a gluten free diet, but don’t test positive for celiac disease, are thought to have non-celiac gluten sensitivity. However, a closer look at this population is raising some doubts. Researchers in Spain analyzed data from 10 studies comprising 1312 adults, all of which were double blind, placebo controlled gluten challenges (meaning that neither the researchers nor the participants knew if they were getting a gluten-free diet or the gluten-containing placebo).  Only 16% of the non-celiac gluten sensitivity patients showed gluten-specific symptoms when exposed to the gluten-containing diet, and 40% of them had similar or increased symptoms when on the gluten-free control diet. The researchers conclude that these results “cast doubt on gluten as the culprit food component in most patients with presumptive [non-celiac gluten sensitivity].”  
Perspectives in Clinical Gastroenterology and Hepatology. 2017 Mar:15(3):339-348. (Molina-Infante J et al.) 

Low Gluten Diet Linked with Diabetes

For those without a medically diagnosed gluten issue (such as celiac disease), the support for gluten-free and low-gluten diets appears to be more fad than fact. In a study of nearly 200,000 health professionals, researchers at Harvard found that eating lower amounts of gluten is related to a higher risk for type 2 diabetes. In fact, those in the top 20% of gluten intake were 13% less likely to get type 2 diabetes over the 30-year study period, even after adjusting for family history, exercise habits, weight, and calorie intake. (Note that research presented at meetings is considered preliminary until published in a peer reviewed journal.)
Presented at the American Heart Association’s Epidemiology and Prevention / Lifestyle and Cardiometabolic Health 2017 Scientific Sessions. Portland, OR. March 9, 2017. (Zhong G et al.)

Whole Plant Foods, Not Fads, Best for Heart Health

Magazines and news articles often jump from one “superfood” or fad diet to the next, but not all nutrition advice is backed up by substantial evidence. In this review, researchers analyzed the scientific support for various trending “heart healthy” foods and diets. Eating berries, nuts, extra virgin olive oil, leafy green vegetables, and plant-based diets are all strongly linked with better heart-health based on numerous studies. On the other hand, coconut oil, palm oil, eggs, juicing, and southern diets are linked with potential harm. Additionally, the researchers found no support that gluten-free diets are beneficial for people without gluten related disorders. The authors conclude that “Evidence-based healthy dietary patterns are high in fruits, vegetables, whole grains, legumes, and nuts in moderation, although some may include limited quantities of lean meats (including poultry and seafood), low-fat dairy products, and liquid vegetable oils.”
Journal of the American College of Cardiology. 2017 March 7;69(9):1172-87.

Eating Gluten at an Early Age Not Related to Celiac Disease in Most High Risk Children

Celiac disease, which effects an estimated 1% of the population, is an autoimmune disease that requires strict, lifelong adherence to a gluten-free diet. Eating gluten early in life for certain at-risk populations has been suggested to increase celiac disease risk, but there has been little evidence to support this notion. To better understand this relationship, scientists analyzed data from 715 children at high risk of developing celiac disease. The children, from 5 European countries, were randomly assigned how much gluten to eat from 4 or 6 months through 10 months of age. Findings show that gluten intake showed no relationship with celiac disease development risk over the next 6 years, except in children with a specific genotype (HLA-DQ2.2/-DQ7).
American Journal of Clinical Nutrition. 2017 February 22;105(4):890-896. (Crespo-Escobar P et al.) 

Gluten Free Diet Has No Effect on Non-celiac Athletes

A common belief among athletes is that going gluten-free might help performance. To investigate this popular belief, Australian scientists randomly assigned 13 competitive cyclists without celiac disease to a 7 day gluten containing diet or a 7 day gluten free diet. The cyclists then went through a 10 day washout period, before trying the other diet, serving as their own controls. There was no significant difference in time trial performance of the athletes on either diet, nor were there significant differences in markers of inflammation or intestinal injury.
Medicine and Science in Sports and Exercise. 2015 Dec;47(12):2563-70.

Gluten Free Foods Are Not Healthier

While most whole grains are naturally gluten free (like quinoa, millet, and rice), many gluten-free packaged foods are made with refined, starchy flours, such as potato flour or white rice flour. To see how gluten free products stack up, researchers analyzed the nutrition on over 3200 food products in Australia, comparing the health of gluten free items to items containing gluten. Gluten free products were found to have significantly less protein across all major food groups, and gluten free pasta was found to be significantly less healthful than regular pasta (based on the Australian government’s “Health Star Rating”). Other than that, the researchers found no significant health differences between gluten free (GF) and gluten-containing products, concluding that “the consumption of GF products is unlikely to confer health benefits, unless there is clear evidence of gluten intolerance.”
British Journal of Nutrition. 2015 Jun 29:1-7. [Epub ahead of print]. (Wu JH et al.)

Early Infant Feeding and Celiac Prevention

At the Medical University of Warsaw, researchers participating in an international project investigating early-life factors that may prevent celiac disease in genetically-predisposed people found several factors that may be involved. Although evidence is still limited, the scientists advise avoiding both early (before 4 months) and late (after 7 months) introduction of gluten; it also seems that introducing gluten while the infant is still being breast-fed may be protective.

Alimentary Pharmacology & Therapeutics, 2012 August 21. [Epub ahead of print] (Szajewska et al.)

Buckwheat Enhanced Gluten-free Bread a Healthier Gluten-free Alternative

Researches from the Polish Academy of Sciences recently published a study suggesting substituting some or all of the corn starch in many traditional gluten-free bread recipes with buckwheat flour. In addition to providing higher levels of antioxidants, B vitamins, magnesium, phosphorus and potassium, the study indicated that swapping 40% of the corn starch for buckwheat flour also increased its “overall sensory quality” when compared to the gluten-free bread used in the control. Although recipes were tested with anywhere from 10-40% buckwheat flour, the conclusion clearly points to the 40% buckwheat flour results as having the most nutritional benefits for celiac sufferers.
International Journal of Food Science and Technology, October 2010; 45(10):1993–2000. Epub August 25, 2010.

Amaranth Offers Advantages for Gluten Free Baking

Many gluten-free products are low in nutrients, and offer technological challenges to food processors. Scientists at the Research Center for Food and Development in Hermosillo, Mexico, experimented with amaranth, a food with a long culinary tradition in Mexico. They found that bread formulation with 60-70% popped amaranth flour and 30-40% raw amaranth flour produced loaves with an even crumb and higher volume than most gluten-free breads, and that cookies formulated with 20% popped amaranth flour and 13% whole grain popped amaranth also worked out well. Both foods offered acceptible dough functionality without some of the additives often needed in GF foods, and the final foods had a very high nutritional value.
Plant Foods for Human Nutrition, August 24, 2010 [Epub ahead of print]

Naturally Gluten-Free Grains May Be Cross-Contaminated

A Polish team from the Instytut Zywnosci in Warsaw analyzed 22 gluten-free products and 19 naturally gluten-free grains and flours, for gluten content. Gluten content in the products ranged from 5.19 to 57.16 mg/kg. In the inherently gluten-free grains and flours, no gluten was detected in rice and buckwheat samples, but was detected in rice flakes (7.05 mg/kg) in pearl millet (27.51 mg/kg) and in oats (>100 mg/kg). ?(Poland)
Rocz Panstw Zaki Hig. 2010; 61(1):51-5. ??

Meanwhile, in the U.S., Tricia Thompson, MS, RD, a nutrition consultant specializing in gluten-free diets, arranged for gluten-testing of 22 retail samples of inherently gluten-free grains, seeds, and flours. She found contamination of 20 to 2925 ppm in seven of 22 samples, putting them over the proposed FDA limit of 20 ppm, with lower levels in some others. Both articles point to the importance of gluten-free certification even on foods that are naturally gluten-free, such as millet.?(USA)
Journal of the American Dietetic Association. June 2010; 110(6):937-40.

Oats May Boost Nutrition Profile of Gluten-free Diets

Two recent studies out of Scandinavia show that adding oats to a gluten-free diet may enhance the nutritional values of the diets, particularly for vitamins and minerals, as well as increasing antioxidant levels.  Researchers asked 13 men and 18 women with Celiac disease to follow a gluten-free diet with the addition of kilned (stabilized) or unkilned oats.  After six months, the addition of stabilized oats resulted in an increased intake of vitamin B1 and magnesium, while the unkilned oats increased intakes of magnesium and zinc.  In the second study from Scandinavia, the addition of gluten-free oats allowed people on gluten-free diets to achieve their recommended daily intakes of fiber, as well as increasing levels of a particular antioxidant called bilirubin, which helps the body eliminate free radicals as well as protect the brain from oxidative damage.
European Journal of Clinical Nutrition, January 2010; 64:62-67, DOI:10.1038/ejcn.2009.113 and
The European e-Journal of Clinical Nutrition and Metabolism, December 2009; e315-e320

Gluten Free Diet Decreases Good Gut Bacteria

Although most whole grains are naturally gluten free, many gluten free diets are devoid of these prebiotic, nutrient powerhouses. In an effort to see how eliminating gluten effects the gut microbiome, Spanish researchers assigned ten healthy adults (average age 30) to a gluten free diet for one month, and measured the changes in their gut microbiome. In just one month of eliminating gluten, the good bacteria in their gut significantly decreased, and some harmful bacteria (like E. Coli) increased, although not significantly. This research suggests that those on a medically prescribed gluten free diet should take care to consume foods that are associated with good gut bacteria, such as gluten-free whole grains, fruits, and vegetables.
British Journal of Nutrition. 2009 Oct;102(8):1154-60. (De Palma et al.)

More Protein, Minerals, Fiber in Quinoa

Anne Lee and colleagues at Columbia University’s Celiac Disease Center found that the nutritional profile of gluten-free diets was improved by adding oats or quinoa to meals and snacks. Most notable increases were protein (20.6g vs 11g) iron (18.4mg vs 1.4mg, calcium (182mg vs 0mg) and fiber (12.7g vs 5g
Journal of Human Nutrition and Dietetics, August 2009; 22(4):359-63. Epub 2009 Jun 10.

Sorghum is Safe for People with Celiac Disease

Up to one percent of the U.S. population (and about ½% worldwide) is believed to have Celiac Disease, an autoimmune reaction to gluten proteins found in wheat, barley and rye. While sorghum has long been thought safe for celiacs, no clinical testing had been done until researchers in Italy made a study. First, they conducted laboratory tests; after those tests established the likely safety, they fed celiac patients sorghum-derived food products for five days. The patients experienced no symptoms and the level of disease markers (anti-transglutaminase antibodies) was unchanged at the end of the five-day period.
Clinical Nutrition. 2007 Dec;26(6):799-805. Epub 2007 Aug 24

Nutrient Changes Noted in Sprouted Wheat

German researchers sprouted wheat kernels for up to 168 hours (1 week), analyzing them at different stages to learn the effects of germination on different nutrient levels. While different times and temperatures produced different effects, overall the sprouting process decreased gluten proteins substantially, while increasing folate. Longer germination times led to a substantial increase of total dietary fiber, with soluble fiber tripling and insoluble fiber decreasing by 50%.
Journal of Agriculture and Food Chemistry, June 13, 2007; 55(12):4678-83. Epub 2007 May 12.

Less Allergenic Wheats Identified

Scientists in Shizuoka, Japan screened 324 varieties of wheat from around the world, in an effort to find varieties less likely to trigger allergies to gluten, gliadin, and alpha-amylase inhibitor. Einkorn, along with rare varieties from Mexico, Ecuador, China, and Italy, were found to be among the least allergenic.
Journal of Nutritional Science and Vitaminology (Tokyo), June 2005; 51(3): 204-6