February 18th, 2013 by Digestive Detective
While many physicians and those in the public health arena still scoff at the idea that gluten is problematic in the diet, a variety of new clinical studies point to the numerous deleterious effects that this protein can have on individuals. Recent research findings have exhibited gluten's influence on weight gain as well as its implications to those suffering from irritable bowel syndrome. As more findings abound, it's becoming clear that for a large portion of the population, gluten-containing foods result in health issues that appear to resolve or greatly improve when gluten is removed from the diet.
Gluten & Weight Gain
Although "going gluten-free" as a dietary, weight loss approach may not itself be a particularly strong strategy for overall weight loss, some studies now support the idea that gluten-based diets may result in increased body fat and insulin resistance. A study published in the Journal of Nutritional Biochemistry examined the effects of a high-fat, gluten-containing diet in comparison with a high-fat, gluten-free diet. In the study, mice were fed a high-fat diet containing 4.5% gluten (Control) or no gluten (GF) with the following measured:
- Body weight and adiposity gains
- Inflammatory biomarkers (leukocyte rolling and adhesion, macrophage infiltration,cytokine production)
- Blood lipid profiles
- Glycaemia and insulin resistance
- Genetic expression (Expression of the PPAR-α and γ, lipoprotein lipase (LPL), hormone sensitive lipase (HSL), carnitine palmitoyl acyltransferase-1 (CPT-1), insulin receptor, GLUT-4)
The markers indicated that "Gluten-free animals showed a reduction in body weight gain and adiposity, without changes in food intake or lipid excretion." Fat burning physiological mechanisms were also shown to be favorable with an upregulation of PPAR-α, LPL, HSL and CPT-1; all indicators of fatty acid oxidation and lipolysis. The researchers concluded:
"Our data support the beneficial effects of gluten-free diets in reducing adiposity gain, inflammation and insulin resistance. The data suggests that diet gluten exclusion should be tested as a new dietary approach to prevent the development of obesity and metabolic disorders."
Impact on Irritable Bowel Syndrome
It seems logical to assume that since gluten serves as an irritant to the gut in those with intolerance or Celiac disease that it may also irritate the gut in those with an already compromised gastrointestinal systems such as those suffering from irritable bowel syndrome (IBS). While the mechanisms may be different, it's not a huge leap to make this connection but making such inference without the backing of clinical trials and research findings is often what gives conventional medicine practitioners and experts the fodder for dismissal of gluten as being the culprit in health conditions and physiological response; that is, until such clinical trials and research surfaces.
Just last month, the Journal of Gastroenterology published the results of a randomized, controlled 4-week trial (the gold standard in research) examining the effects of a gluten-free diet in patients with irritable bowel syndrome (diarrhea predominant/IBS-D); specifically its effects on bowel frequency and intestinal function. The study, conducted by researchers from the Mayo Clinic, measured daily bowel function, small bowel (SB) and colonic transit, mucosal permeability (by lactulose and mannitol excretion), and cytokine production by peripheral blood mononuclear cells (PBMCs) following exposure to gluten and rice. The patients were analyzed for genetic predisposition to gluten intolerance through genotype analysis (identification of HLA-DQ2 and HLA-DQ8 genetic markers) and separated into 2 groups: gluten-containing diet (GCD) and gluten-free diet. Subjects on the GCD experienced more bowel movements per day (already an issue for IBS-D patients), higher small bowel permeability (particles/molecules seeping into general circulation via loosening of normally tight intestinal junctions), and significant decreases in expression of the genes that are components of tight junction strands (ZO-1, claudin-1, and occludin). When these genes are not expressed, then an opening or loosening of the tight junctions in the intestinal tract occurs more easily, causing food molecules that typically are not meant to escape to leak out, resulting in an immune response. The most significant example of this is the autoimmune response seen in Celiac disease, but other autoimmune conditions may be impacted from this as well. Molecular mimicry (when the body mistakes the cells of a particular gland or tissue for an invading antigen) is an example where the body mounts an immune attack on our own body tissues and cells in a case of mistaken identity. Integrative practitioner Chris Kresser has written exclusively about this in articles relating the connection between gluten and the thyroid. The results of this study showed that those genetically predisposed to gluten intolerance via the gene analysis were impacted more significantly across all measures, but that, as stated above, all individuals, both with the genotype and those without, experienced adverse effects to the aforementioned biomarkers and physiology.
The most telling and interesting aspect of this particular study is the conclusion reached by the researchers:
"Gluten alters bowel barrier functions in patients with IBS-D, particularly in HLA-DQ2/8-positive patients. These findings reveal a reversible mechanism for the disorder."
The reversible mechanism for the disorder - removing gluten from the diet - appears to have the potential to reverse the adverse effects displayed in IBS-D patients once they are no longer consuming gluten. This is significant as this not only infers the effects that gluten has on this population, but provides a tangible, actionable strategy for improving symptoms and easing the GI-related response experienced by these individuals.
In summary, these studies add to the growing body of evidence that link gluten to a variety of mechanisms that affect a wide-range of conditions and physiological responses in the body. While it may not be protocol as of yet to encourage all individuals to consider a gluten-free diet, these findings offer a strong argument that gluten-containing foods are problematic for an increasingly larger portion of the population and that the removal of this component for the diet is, at the very least, beneficial for a trial period to ascertain its influence on current health conditions and overall function.