Jane, a GERD patient who happens to be a nutritionist and ketogenic diet advocate, presented to my office for evaluation of GERD related symptoms of several year duration. She is frustrated with her GERD symptom progression and severity over the past few years despite maintain a healthy lifestyle for the past 30 years. She has a strong family history of GERD and unlike her patients, a ketogenic diet did not help alleviate her acid reflux related symptoms. She reports that she has helped many of her patients control their acid reflux symptoms by adopting a very low carbohydrate, high fat diet, known as ketogenic or keto diet. Keto diet, however, did not eliminate her GERD symptoms. She is otherwise healthy and fit. She exercises daily and maintains a normal body weight. Given the popularity of keto diet, I have encountered a number of GERD patients like Jane and her patients reporting acid reflux symptom improvement on ketogenic diet. Such observations are unexpected. We advise our GERD patients to avoid fatty food to decrease the incidence of heartburn. So why and how does a ketogenic diet help alleviate heartburn?
The relationship between diet and GERD is well recognized but not well studied. For instance, spicy food, alcohol, and chocolate exacerbates acid reflux, but the underlying mechanism is not known. A heavy meal rich in fat is more likely to cause heartburn than a light meal consistent of lean meat and fresh vegetables. Fat like smoking, alcohol, chocolate and mint… is believed to decrease the lower esophageal sphincter pressure favoring acid reflux. GERD, however, is a multifactorial problem. GERD pathophysiology is not limited to lower esophageal sphincter pressure and relaxation. GERD is in fact a gastroduodenal motility disorder that favors reflux of gastric content into the esophagus. Ingested food alters gastrointestinal motility in a number of ways that we still don’t understand. In the case of GERD, certain ingested foods alter gastric motility in such a way to favor reflux. Along those lines, we have noticed that a low carbohydrate diet in obese patients reduces heartburn events. A study published in 2006 in the journal of Digestive Diseases and sciences, by Shaheen NJ et al, demonstrates that a very low carbohydrate diet in obese patients with GERD significantly reduces distal esophageal acid exposure. The authors enrolled 8 patients. Each participant underwent a 24-hour pH impedance study prior then 6 days after starting a diet containing less than 20 grams of carbohydrates per day. Both the DeMeester score and percent total time with pH less than 4 significantly decreased. All patients reported improvements in heartburn, chest pressure, excessive burping and other GERD related symptoms. The study is too small to draw any major conclusion, but the results do suggest decreased acid reflux on low carbohydrate diet in obese patients prior to any significant weight loss. 80% of obese individuals suffer from GERD. A high intra-abdominal pressure causes gastric lumen content to reflux back into the esophagus. Furthermore, obese patients suffer from abnormal carbohydrate digestion, absorption and metabolism. Post-prandial hormones secreted by the gastro-intestinal tract like GLP-1 and PYY are diminished in obese patients. This results in elevated post-prandial blood glucose and insulin levels. Dysfunctional gastric emptying along the Magenstrasse pathway results in decreased post-prandial GLP-1 and PYY secretion. It is also possible that disrupted Magenstrasse emptying results in acid reflux. Indeed, Nissen fundoplication, the most reliable treatment for acid reflux, increases postprandial GLP-1 and PYY secretion. Nissen fundoplication increases gastric emptying and possibly restores a dysfunctional Magenstrasse emptying pathway.
Along those lines, a very low carbohydrate and high fat diet, like ketogenic diet, may be of great benefit to obese GERD patients. Keto diet may be particularly effective in reducing heartburn in overweight and insulin resistant individuals (the majority of adult US population). GERD is also a chronic and progressive disease. Patients with stage 3 and 4 GERD are less likely to benefit from just diet and lifestyle changes. Advanced GERD is associated with abnormal anatomy (hiatal hernia), esophageal dysmotility (detected on manometry) and significant gastric emptying issues (still poorly misunderstood and cannot be measured). Nissen fundoplication with hiatal hernia repair address these issues and provide a reliable and durable cure for advanced acid reflux disease.