Public Release:  Researchers investigate impact of lifestyle on GI health

Vegetarian diet reduces risk of colon cancer; fatty soup as appetizer means eating less for dinner

American Gastroenterological Association

WASHINGTON, D.C. (May 21, 2007) -- According to new research presented today at Digestive Disease Week® 2007 (DDW®), lifestyle factors like choosing your diet regimen or ordering an appetizer for dinner may have a significant impact on the gastrointestinal (GI) system, affecting your risk for certain diseases, weight and general GI-related activity. DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"Many factors come into play when managing a healthy lifestyle. While some factors may be difficult for patients to change, other simple adjustments, such as adopting a vegetarian diet early in life or ordering the appropriate soup while eating out, may result in decreased risk for obesity and colon cancer," said Alan Buchman, M.D., MSPH, AGAF, Feinberg School of Medicine of Northwestern University School of Medicine. "The studies presented today further demonstrate how researchers are beginning to understand the links between digestive diseases and lifestyle - most notably, diet."

Life Long Vegetarian Diet Reduces the Risk of Colorectal Cancer (Abstract #155)

The average person's lifetime risk of developing colorectal cancer (CRC) is about seven percent and the role of diet in preventing this type of cancer remains under debate. Most of all, previous studies enrolled middle-aged subjects, raising the possibility that CRC development may start before common interventions. Researchers from Tata Memorial Hospital (TMH) in Mumbai, India, set out to determine whether a vegetarian diet is associated with reduced risk of CRC if started very early in life.

In this study, researchers used a prospectively created database of 8,877 Indian patients managed in a clinical nutrition service from January 1, 2000 through December 31, 2005, to examine the association of life-long vegetarianism with incidence of CRC. During the evaluation for nutrition support, a history of life-long vegetarianism (due to religious reasons) was obtained from all patients to plan an appropriate diet. Twenty-seven percent of subjects (2,092 patients) from the control cohort were life-long vegetarians and 22.4 percent (178 patients) of subjects with colon cancer were vegetarians.

Patients with colorectal cancer (n=796) comprised the primary patient cohort for this study. Three groups of controls were generated from the same database for separate comparison with the CRC cohort. These included all patients with non-CRC cancers (control group one: n=7,273), patients with non-CRC and tobacco-related cancers (control group two: n=1,844), and patients with benign disorders (control group three: n=74). Multivariate analysis of 7,641 patients was performed by adjusting for age, gender, body mass index and economic status.

Vegetarianism was significantly associated with patients over 65 years, male gender, body mass index (BMI) of less than 20 Kg/m2 and economic deprivation. Colorectal cancer was positively associated with old age and male gender, and inversely associated with vegetarian diet, low BMI and economic deprivation. The inverse association of CRC and lifelong vegetarianism was observed with all the three control groups.

"A well-planned vegetarian diet is a healthy way to meet your nutritional needs," said Yogesh M. Shastri, M.D., of Johann Wolfgang Goethe University Hospital, Frankfurt, Germany and previously a co-author of this study at TMH, Mumbai, India. "The exact mechanism by which life long vegetarianism may reduce the risk of sporadic CRC needs further investigation. Prolonged vegetarianism starting in early life may be a viable lifestyle option for those at risk of developing the disease."

Dr. Shastri will present this study on Sunday, May 20, at 11:45 a.m. in Room 143A.

Fatty Soup as an Appetizer Reduces Food Intake in Lean and Obese Subjects (Abstract #S2191)

Many people believe that ordering an appetizer can actually make you hungrier and that you tend to eat more of your entrée as a result. However, researchers from the University of Texas Medical Branch in Galveston, Texas, feel that what you order as a starter determines your overall appetite, as absorption of fat in the small intestine induces the feeling of being full and slows down gastric emptying. The aim of this study was to investigate whether a fatty soup consumed before a meal might reduce food intake in both lean and obese subjects and whether this possible inhibitory effect would be related to changes in gastric functions.

For the study, investigators recruited 12 lean and 12 obese healthy subjects and invited each group to the lab for two sessions (eating both fatty soup and protein soup with the same number of calories and volume). Each session consisted of a 30-minute baseline of soup consumption, a 20-minute post-soup period, an "all you can eat" pizza meal, and a 60-minute post-meal period. Electrogastrogram (a test recording the electrical activity of the stomach, EGG) and electrocardiogram (a similar test recording electrical activity of the heart, ECG) were recorded during each session. Food intake was assessed by the caloric count of the consumed pizza. Several symptoms, including satiety, appetite and nausea, were rated at different times of the study. In a second study, subjects were given the soup appetizer and then taken to an "all-you-can-eat" pizza buffet together in a social setting.

When compared with the protein soup, the fatty soup significantly reduced the amount of caloric intake with the following meal in both lean (962.0 vs. 1,188.5 calories) and obese (1,331.9 vs. 1,544.6 calories) subjects. A similar reduction in caloric intake was noted in lean subjects eating in the social setting (1,555 vs. 1,825 calories), except that significantly more food was consumed in social sessions compared with the lab setting.

In addition to general caloric intake, obese subjects registered a higher appetite level after the soups than the lean controls (protein: 8.75 vs. 5.92; fat: 8.08 vs. 5.17). The percentage of normal stomach electrical rhythmi was similar between the lean and obese subjects (73.9% vs. 68.9%) before fatty soup, and was reduced after the fatty soup in the lean, but not in the obese (59.7% vs. 73.9%). Also, the obese showed a higher sympathovagal balance (1.59 vs. 0.78) and sympathetic activity (0.55 vs. 0.42) compared to the lean patients, but a lower vagal (nerve in the stomach that controls the making of stomach acid) activity (0.45 vs. 0.58).

"In this study, we found that fatty soup as an appetizer reduces food intake by about 20 percent in both lean and obese subjects and may have a therapeutic potential for obesity," said Jiande Chen, Ph.D., of the University of Texas Medical Branch and senior author of the study. "Our hope is that further studies with similar outcomes may curb those myths and that people will think about what certain foods often thought to be off-limits may be able to achieve for their overall health and weight."

Dr. Chen will present this study on Sunday, May 20, at 8:00 a.m. in Hall E.

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Digestive Disease Week® (DDW®) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW takes place May 19-24, 2007 in Washington, D.C. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology.

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