Coexistence of Obesity and GERD...coincidence?

Gastro esophageal reflux disease (GERD) is a common disorder defined as abnormal reflux stomach contents into the esophagus. Symptoms include heartburn, acid regurgitation, damage in the esophagus, and may lead to long-term complications. Incidences of GERD increase every year, coinciding with the increased obesity rates (1).

Diet is case-based but generally has no effect on GERD symptoms.

Old experimental and clinical studies have shown that eating foods such as chocolates, coffee, citrus, gas forming foods, and fatty foods causes loosening of lower esophageal spincter pressure and an increase in esophageal acid exposure. These lead physicians to advising patients to avoid suspecting foods (2).

Kaltenbach (2) and colleagues performed a systematic review of literature on studies done between 1975 and 2004 to examine the effects of dietary lifestyle modification to GERD. Of the 2039 relevant studies from search databases, 100 were included in this analysis. Papers were reviewed and categorized according to evidence-based ratings of A through E. When the majority of well-designed controlled trials consistently agree on their findings, the diet intervention or diet cessation is considered to be of High quality (evidence A). On the other hand, studies with conflicting findings on the effect of a diet falls under Evidence E, indicating there is poor evidence.

If we examine this table, It appears that only losing weight and elevating the height of bed (HOB) improved the symptoms of GERD by improving pH, and there is poor evidence on diet's influence in inducing symptoms (2)

In a published article by Stanford University School of Medicine (3) on Current Developments in the Management of Acid-related GI-disorders, they elucidated that as practitioners, they no longer recommend eliminating all of food items associated with GERD symptoms because it lacks supporting data. However, they consider the dietary recommendations on a case-by-case basis, telling patients to look for cause-and-effect relationships between specific foods and GERD symptoms. For example, if they notice that every time they eat spicy foods they have heartburn, they should eliminate spicy foods in their diet (3).

Excess weight and GERD

A study done in Temple University, Philadelphia examined the prevalence risk of GERD among 500 hospital patients (4). They were asked to fill out a survey questionnaire with detailed questions on GERD including frequency, severity, episodes of regurgitation, and nocturnal symptoms. Records on visits to physicians regarding GERD were also included.

They found that smoking and waist circumference appears to be a risk factor for GERD. Compared to those with a waist circumference of 33 and lower, those with a waist line of 42 inches and above have twice (2.15) more likelihood to develop GERD symptoms (4).

Lets look at a similar study in India...

In new delhi, Physicians interviewed the employees of All India Institute of Medical Sciences (AIIMS) regarding GERD symptoms, and collected information on their profiles and medical histories(5). Their findings agree with the first study we discussed in which, the major risk factors for GERD are higher BMI, smoking, current smoking, and presence of asthma or hypertension.

The Pressure in Being Overweight

Inconsistent evidences dismissed the role of diet as primary culprit for GERD. It is postulated that mechanical mechanisms in obesity are responsible for this disorder (6).

A bigger waistline is associated with increased pressure in the stomach that pushes gastric juice upward to the esophagus (6). Moreover, it was observed that most cases of hiatal hernia cases were observed in patients who are overweight (6).

Hiatal Hernia

Hiatal hernia is diagnosed when the stomach moves up into the chest through the opening in the diaphragm. It is believed to be caused by increased pressure in the abdomen from pregnancy, obesity, coughing, or straining during bowel movements.

In a study by Wilson (7), characteristics of patients with Hiatal hernia were compared with healthy subjects. They found that overweight people have are 2.5 times more likely to develop hiatal hernia than their lean counterparts, while those who are obese are 4 times more likely to get this condition. This influence of fat mass is thought to be independent from age, sex, or race.

Mechanical Gastric Disorders in Obesity

In an attempt to explain the mechanisms of GERD in obese patients, Kuper (8) looked at the differences in lean (Group 1) vs obese subjects (Group 1-4) in terms of gastrointestinal movements.

They found that compared to lean patients, obese patients have low pressured Lower esophageal sphincter (LES), indicating a weak barrier between the stomach and the esophagus.

Obese patients also have lower esophageal contraction, but faster movement in the esophagus. They noted that these factors, along with the presence of hiatal hernias are responsible for GERD in overweight patients(8).

The Role of Inflammatory Hormones

The exact mechanisms for GERD still remain unclear (9). Recent studies now show the role of inflammatory hormones such as Interleukin -8 (IL-8) in development of GERD symptoms.

Using endoscopy biopsy, GERD patients were found to have significantly higher levels of IL-8. Moreover, they found that IL-8 levels increases parallel to the increase of severity in GERD patients with esophagitis(9).

The connection between IL-8, GERD and Adiponectin

Abdominal fats act like a reservoir for inflammatory hormones and expansion of these fat tissues results in increased production of inflammatory hormones that circulates the body (10).

In humans with normal metabolism, the abundant presence of anti-inflammatory hormones- adiponectin in the circulation stops the production of inflammatory hormones (10). However, production of adiponectin is suppressed in obese people when excessive fat tissues produce inflammatory hormones that overwhelm adiponectin (11). This is supported by studies showing that obese subjects have significantly lower adiponectin levels than lean subjects and weight loss induces its increased levels (10).

Weight Reduction and GERD

A number of weight-reduction interventions appear to improve GERD symptoms. For example, dietary advice resulted in decreased symptoms. On the other hand, bariatric surgery particularly the Roux en Y gastric bypass is found to be the most effective in reducing GERD symptoms by diverting bile away from the esophagus, reducing the volume of reflux, and eliminating acid production.

Take-home Message: While diet is dismissed to be the major player in the development of GERD symptoms, diet-induced weight loss would still be useful to reduce body fat responsible for inflammation.

References:

1) Festi, D. (2009). Body weight, lifestyle, dietary habits and gastroesophageal reflux disease. World Journal of Gastroenterology, 15(14), 1690. doi:10.3748/wjg.15.169

2) Kaltenbach, T., Crocket, S., Gerson, L.B. (2006). Are Lifestyle Measures Effective in Patients With Gastroesophageal Reflux Disease? American Medical Association. 166, 965–971.

3) Gerson, L. B. (2009). The Effects of Lifestyle Modifications on GERD. Current Developments in the Management of Acid-Related GI disorders. Gastroenterology & Hepatology. 5(9), 613–615.

4) Friedenberg, F. K., Rai, J., Vanar, V., Bongiorno, C., Nelson, D.B., Parepally, M., Poonia, A., Sharma, A., Gohel, S., Richter, J.E. (2011). Prevalence and risk factors for gastroesophageal reflux disease in an impoverished minority population. Obes Res Clin Pract. 2010 October ; 4(4): e261–e269.

5) Sharma, P. K., Ahuja, V., Madan, K., Gupta, S., Raizada, A., & Sharma, M. P. (2011). Prevalence, severity, and risk factors of symptomatic gastroesophageal reflux disease among employees of a large hospital in northern India. Indian Journal of Gastroenterology : Official Journal of the Indian Society of Gastroenterology, 30(3), 128–34. doi:10.1007/s12664-010-0065-5

6) Ierardi, E., Rosania, R., Zotti, M., Principe, S., Laonigro, G., Giorgio, F., … Panella, C. (2010). Metabolic syndrome and gastro-esophageal reflux: A link towards a growing interest in developed countries. World Journal of Gastrointestinal Pathophysiology, 1(3), 91–6. doi:10.4291/wjgp.v1.i3.91

7) Wilson, L. J., Ma, W., & Hirschowitz, B. I. (1999). Association of Obesity With Hiatal Hernia and Esophagitis. The American Journal Of Gastroenterology. 94(10).

8) Küper, M. a, Kramer, K. M., Kirschniak, a, Kischniak, a, Zdichavsky, M., Schneider, J. H., … Granderath, F. a. (2009). Dysfunction of the lower esophageal sphincter and dysmotility of the tubular esophagus in morbidly obese patients. Obesity Surgery, 19(8), 1143–9. doi:10.1007/s11695-009-9881-z

9) Isomoto, H., Nishi, Y., Kanazawa, Y., Shikuwa, S., & Mizuta, Y. (2007). Serial Review Pleiotropic Effects of Proton Pump Inhibitors Guest Editor : Yuji Naito Immune and Inflammatory Responses in GERD and Lansoprazole, (September), 84–91.

10) Lihn, A. S., Pedersen, S. B., & Richelsen, B. (2005). Adiponectin : action , regulation and association to insulin sensitivity, (5), 13–21.

11) Ouchi, N., & Walsh, K. (2007). Adiponectin as an anti-inflammatory factor. Clinica Chimica Acta; International Journal of Clinical Chemistry, 380(1-2), 24–30. doi:10.1016/j.cca.2007.01.026