Li Jiao, MD, PhD, MS
Hashem B. El-Serag, MD, MPH
Department of Medicine
Baylor College of Medicine
2002 Holcombe Blvd, MS 152
Houston, TX 77030
(713) 791-1414 ext 10322 / (713) 748-7359 (FAX)
jiao@bcm.edu / hasheme@bcm.edu

“Dietary Consumption of Meat, Fat, Animal Products and Advanced Glycation End-Products and the Risk of Barrett’s Oesophagus,”

Aliment Pharmacol Ther, 2013 Oct;38(7):817-24. 49755 (10/2013)
Li Jiao: Can you please share with us your educational background and current position?
Li Jiao and Hashem El-Serag: Dr. Jiao earned MD and MS degree in China and attained a PhD degree in the United States. She received training in medicine, molecular and nutritional epidemiology. She is currently  an Assistant Professor of Medicine at Baylor College of Medicine. Dr. El-Serag is the Chief of Gastroenterology and Hepatology and is an experienced epidemiologist in digestive diseases.

KH: What got you interested in studying the role of diet and Barrett’s esophagus (BE), and in particular the consumption of animal products?

LJ: I have a long standing research interest on diet and gastrointestinal cancers. Previous studies have shown a positive association between meat and fat intake and risk of esophageal adenocarcinoma. BE is a well-known pre-cancerous lesion for esophageal adenocarcinoma. However, the association between BE and meat and fat intakes has not been well examined.

KH: How prevalent is BE, its morbidity and mortality, and adverse sequelae?

HBE and LJ: It is estimated that approximately 1% of the general population, and 6-10% of people with weekly gastroesophageal reflux symptoms (e.g. heartburn or acid regurgitation) have BE. BE can be complicated with esophageal dysplasia, which signals a marked increase in the risk of esophageal adenocarcinoma. The risk of esophageal adenocarcinoma, which is the fastest rising cancer in white men in the United States, develops annually in 0.5% of non-dysplastic Barrett’s and more than 5% in patients with high grade dysplasia per year. Survival with esophageal adenocarcinoma is dismal with a 5 year survival less than 20%.
KH: What actually causes the pathophysiology of BE? Is it mostly dietary? Adverse medication effects?
HEB and LJ: BE is a complication of chronic gastroesophageal reflux disease (GERD). Repeated episodes of acid and non acid reflex cause esophageal mucosal inflammation and leads to a change in the cell type of the mucosa lining of the esophagus. Known risk factors for BE include older age, male sex, and abdominal obesity.  Medications that are used for reflux disease such as proton pump inhibitors, as well as others like aspirin and non steroidal anti-inflammatory medications may reduce the risk of BE. Bisphosphonates that are used to treat osteoporosis may slightly increase the risk of Barrett’s. It is plausible that diet plays a major role in the BE development. However, more investigations are needed to support this notion.

KH: What is the biochemistry of meat, fat and animal product consumption that might alter physiology to create BE?
LJ: This is what we are trying to understand. We propose that AGEs, compounds produced by high temperature cooking of meat, which is associated with oxidative stress and chronic inflammation, may be one of the mechanisms by which meats contribute to a higher risk of BE. BE is known to be associated with increased inflammatory reaction in esophageal mucosa.

KH: What exactly are advanced glycation end-products (AGEs)? How do they harm body tissues? Sound like AGEs would only come from carbohydrate rich foods (glycation….), not foods rich in protein and fat?
LJ: Advanced glycation end products (AGEs) are chemical compounds that get generated through a nonenzymatic reaction between reducing sugars and free amino groups of proteins, lipids, or nucleic acids. The formation of AGEs is a part of normal metabolism. AGEs are also naturally present in uncooked animal-derived foods, and cooking results in the formation of new AGEs within these foods. Excessively high levels of AGEs in tissues and the circulation can be pathogenic. The pathologic effects of AGEs in humans are related to their ability to promote oxidative stress and inflammation by binding with cell surface receptors or cross-linking with body proteins, altering their structure.  AGEs can come from foods rich in protein and fat. Factors that enhance AGEs formation in foods include high lipid and protein content, low water content during cooking, elevated pH and the use of high temperature over a short time period. Processed meat is an example of AGE rich foods and vegetables are an example of low AGE foods.

KH: Can you tell us about your study and the basic results?

LJ: We found that higher self-reported intake of total meats and saturated fat was associated with a significant increase in the risk of having BE. We also found that dietary AGEs may partially explain such an association.

KH: Have there been any diet intervention trials in BE patients or diet or lifestyle trials to prevent BE?

LJ and HBE: We are not aware of any completed intervention trials in BE patients in humans. There have been inconclusive trials of green tea products, and ongoing trials of physical activity.

KH: What dietary and lifestyle behaviors would you recommend to prevent BE? What things should we not do? And what things or foods can we do or eat that would reduce the risk to BE?

HBE and LJ: According to the current research findings, we recommend a diet with a high intake of leafy vegetables and low intake of meat and fat. In addition, maintaining a normal weight and avoiding abdominal obesity may also reduce the risk of BE. Other lifestyle measures related to avoiding and treating gastroesophageal reflux symptoms are to avoid eating and drinking within 2-3 hours of bed time, elevation of the head end of the bed, and avoiding smoking.

KH: How can the public or health professionals use this information?

LJ and HBE: Our earlier study in the same study population found an inverse association between the dietary consumption of dark green vegetables and risk of BE. These two studies should prompt the public or health professionals to adopt or advise their patients with GERD to eat a prudent diet that includes more consumption of leafy vegetables and less meats and fats. KH: Do you have any further comments on this very interesting subject?
LJ: Large prospective studies are required to confirm our study findings. The health impact of dietary AGEs needs to be evaluated.