Diet Review - Gluten-Free
Finding yourself confused by the seemingly endless promotion of weight-loss strategies and anti-cancer diet plans? In this third article in my series on Diet Reviews, I take a look at the Gluten Free diet.
Gluten Free
Gluten is a family of proteins found in grains like wheat, rye, spelt and barley. A gluten-free diet is not new, as it the sole treatment for 1-2% of Americans who have celiac disease, a serious condition where the body attacks the gluten protein. In people with celiac disease, there is an inability to digest gluten, which causes a spectrum of symptoms that range from bloating to intestinal damage. Up to 6% of people have a related stomach-upsetting but less threatening condition called non-celiac gluten sensitivity. With such a small number of people truly needing this diet, it is difficult to understand why gluten-free products topped $12 billion in sales, according to market research.
What is new—and driving these sales upward—is the use of a gluten-free diet for weight loss, partly fueled by celebrity endorsements and personal testimonies of not only pounds quickly shed, but increased energy, improved digestion, and even clearer skin. Consumer surveys reveal that people perceive gluten-free products to be healthier than their gluten-containing counterparts, and almost a third of Americans are now avoiding or reducing their intake of gluten.
How It Works
A gluten-free diet eliminates all foods containing or contaminated with gluten. Gluten is largely ubiquitous in foods, found as a main ingredient (in wheat, rye, barley, blugar, farro, spelt, karmut, semolina, triticale, cross-contaminated oats), in sauces (soy sauce, malt vinegar, flour), and as additives or fillers (maltodextrin, wheat starch).
When first going gluten-free, perhaps the most noticeable change is having to relinquish favorite staples of bread, pasta, cereals, and processed snack foods. Because some of these products, which are typically highly processed, may be low in nutrients and high in calories, one may feel better and even lose some weight soon after removing them from the diet. Although there are now plenty of gluten-free counterparts to take their place, a gluten-free diet usually causes one to revisit naturally gluten-free whole foods like fruits, vegetables, and grains like brown rice, quinoa, and millet. Including these minimally processed, high-fiber foods may also help to promote weight loss and a feeling of well-being.
However, since gluten-containing whole grains contain fiber and nutrients including B vitamins, magnesium, and iron, it’s important to make up for these missing nutrients. Along with consuming naturally gluten-free foods in their whole form like fruits, vegetables, legumes, nuts, seeds, fish, eggs, and poultry, the following whole grains are also inherently gluten-free: Quinoa, White, brown, black, or red rice, Buckwheat, Amaranth, Millet, Corn, Sorghum, Teff, Oats (when not contaminated during growing/processing).
The Research So Far
Though research has explored the effects of a gluten-free diet on gastrointestinal disorders, autism, and fibromyalgia, there is none that examines the diet’s effects on weight loss alone or for general health benefits. Because of the lack of experimental studies on weight loss, some researchers have instead examined the long-term effects of people with celiac disease on gluten-free diets, or who are generally healthy and consume a diet low in wheat and other gluten-containing grains. They have found that gluten-free diets: 1) may promote certain nutrient deficiencies, 2) may increase the risk of some chronic diseases, and 3) may actually cause weight gain.
Intakes of people with celiac disease on a strict gluten-free diet were found to have inadequate intakes of fiber, iron, and calcium. Other research has found gluten-free cereal products to be low not only in those nutrients but also B vitamins including thiamin, riboflavin, niacin, and folate.
In study of over 100,000 people (without celiac disease) found that those who restricted gluten intake were likely to limit their intake of whole grains and experienced an increased risk of heart disease compared with those who had higher gluten intake. Many studies have found that people with higher intakes of whole grains including whole wheat (2-3 servings daily) compared with groups eating low amounts (less than 2 servings daily) had significantly lower risk of heart disease and stroke, type 2 diabetes, and deaths from all causes.
Gluten acts as a prebiotic, feeding the “good” bacteria in our bodies. It contains a prebiotic carbohydrate called arabinoxylan oligosaccharide that has been shown to stimulate the activity of bifidobacteria in the colon, bacteria normally found in a healthy human gut. A change in the amount or activity of these bacteria has been associated with gastrointestinal diseases including inflammatory bowel disease, colorectal cancer, and irritable bowel syndrome.
Research is conflicting, but some studies have shown weight gain or increased BMI in people with celiac disease after starting a gluten-free diet. This may be partly due to improved absorption of nutrients, a reduction in stomach discomfort, and increased appetite after starting the diet. However, another suspected reason is an increased intake of gluten-free processed food options containing high amounts of calories, fat and sugar.
There is no clear definition of non-celiac gluten sensitivity, but the diagnosis is made when a patient reacts negatively to gluten, but celiac disease and allergies have been ruled out. Symptoms of gluten sensitivity include diarrhea, stomach pain, tiredness, bloating and depression.
One study looked at almost 400 people with self-diagnosed gluten intolerance, and investigated whether they improved on a gluten-free diet. The results showed that 26 people had celiac disease, while 2 had a wheat allergy. Only 27 of the remaining 364 people were diagnosed as gluten sensitive. That means that of the 400 who thought they were gluten intolerant, only 55 people (14.5%) actually had an issue with gluten. Therefore, most people who think they're gluten intolerant actually have other causes for their symptoms.
Gluten and "leaky" Gut
Gliadin, one of the proteins found in gluten may contribute to inflammation and increased permeability of the epithelial lining of the gut. And this happens in healthy subjects, as well as those with celiac disease. A healthy gut plays a critical role in the function of your immune system. It also helps extract nutrients from your food, allowing these compounds to enter the bloodstream where they can nourish your body. But the gut also serves as a critical barrier to block harmful substances and undigested food particles from entering the bloodstream.
However, when glutens cause inflammation in the gut, the small spaces between gut cells (called tight junctions) expand, and a wide range of substances that usually never permeate a healthy gut are able to pass through into the bloodstream, which can trigger inflammation in various other parts of the body and trigger auto-immune diseases.
A “leaky” gut has been linked to a host of seemingly unrelated symptoms and chronic diseases including (but not limited to):
Rheumatoid arthritis
Food allergies
Asthma
Eczema
Inflammatory bowel disease
Lou Gehrig’s disease
Cystic Fibrosis
Diabetes
Autism
ADHD
Alzheimer’s disease
Parkinson’s
Brain fog and fatigue
While these conditions may seem disconnected, they share a common root: Inflammation.
Potential Pitfalls
Gluten-free foods wear a health halo, a belief that a food product is healthful even when it may not offer special health benefits for most people. Research has shown that if one aspect of a food is advertised as healthy or people believe it to be healthy (in this case, the term “gluten-free”), there is a tendency to eat more of it. This may promote weight gain. Also, an over-reliance on processed gluten-free products may lead to a decreased intake of certain nutrients like fiber and B vitamins that are protective against chronic diseases.
Bottom Line
Although a gluten-free diet is the primary treatment for celiac disease and may help to alleviate symptoms in various conditions related to gluten sensitivity, there is currently no evidence showing that a gluten-free diet is effective for weight loss or for general health benefits. For individuals who don’t have celiac disease or gluten sensitivity, there is no specific need to restrict gluten consumption. Those with chronic inflammatory conditions however may benefit from a gluten free diet. A healthy dietary pattern typically includes higher amounts of whole grains and lower amounts of refined grains and added sugar. If choosing to go gluten free, as a rule of thumb, it's better to choose foods that are naturally gluten-free, rather than processed gluten-free products which tend to be low in nutrients and high in added sugar or refined grains. For tips on pasta and gluten free options see this related article.