Impact of Weight Loss Surgery on Food Response

Overview of Bariatric Surgery

A recent study published in Cell Reports by researchers from the UK and US explored how bariatric surgery alters the body’s food response. Bariatric surgery involves surgical procedures on the stomach and intestines, primarily aimed at facilitating weight loss. This approach is commonly employed to address obesity and has been shown to alleviate symptoms associated with type 2 diabetes.

Effects on Blood Sugar Levels

Post-surgery, patients often experience lower blood sugar levels, which can be partially attributed to reduced body weight. This reduction enhances the body’s insulin sensitivity, a particularly advantageous effect for diabetic individuals suffering from insulin resistance. Insulin resistance occurs when the body fails to utilize insulin effectively, resulting in elevated blood glucose levels.

Changes in Digestion and Gut Hormones

Bariatric surgery also significantly impacts how food is digested and absorbed in the gastrointestinal tract. Research indicates that certain gut hormones, such as glucagon-like peptide 1 (GLP-1) and peptide YY (PYY), increase following the procedure. However, the connection between these hormonal changes and the surgery itself remained largely unclear until recently.

Investigating GLP-1’s Role Post-Surgery

Study Methodology

In the recent study, researchers focused on the role of GLP-1 in insulin regulation following weight loss surgery. They studied five lean patients who had undergone gastrectomy, a type of bariatric surgery used for treating or preventing gastric cancer. Each participant received Exendin-9, a compound that inhibits GLP-1 activity, alongside a glucose drink.

Insulin Production Mechanism

Typically, glucose intake stimulates insulin production in the pancreas, allowing glucose to be utilized by body cells. However, excessive insulin production can lead to hypoglycemia, a condition characterized by dangerously low blood sugar levels. While bariatric surgery can benefit obese patients with type 2 diabetes, lean patients may be more susceptible to hypoglycemic episodes due to increased insulin sensitivity following surgery.

Findings on GLP-1 and Insulin Production

The study found that Exendin-9 reduced insulin levels in post-surgical patients, preventing the hypoglycemic episodes typically seen in lean individuals after surgery. This led researchers to conclude that GLP-1 is a key contributor to insulin production in the aftermath of bariatric surgery.

Understanding GLP-1 Level Increases

The research also delved into why GLP-1 levels surge following weight loss surgery. The surgical procedure alters the gut’s structure and nutrient absorption process, shifting digestion to lower regions of the gastrointestinal tract where GLP-1 is produced. This anatomical change stimulates more GLP-1 production due to increased nutrient presence in the lower gut.

Conclusions and Future Directions

Implications for Insulin Secretion

The findings elucidate the mechanisms by which insulin production is regulated post-surgery, highlighting GLP-1’s significant role and the influence of anatomical changes resulting from the procedure. The results also suggest potential strategies for managing hypoglycemia in non-diabetic patients who have undergone surgery.

Exploring Less Invasive Treatments

Looking ahead, researchers aim to investigate less invasive treatment options that can replicate the hormonal effects of surgery, potentially offering new avenues for managing obesity and diabetes-related complications.

References

Larraufie P, Roberts GP, McGavigan AK, Kay RG, Li J, Leiter A, et al. Important role of the GLP-1 axis for glucose homeostasis after bariatric surgery. Cell Rep. 2019 Feb;26(6):1399-1408.
Kaiser Permanente. How insulin works [Internet]. Seattle, WA: Kaiser Foundation Health Plan of Washington; [updated 2014 Jan 3; cited 2019 Feb 16]. Available from: https://wa.kaiserpermanente.org/healthAndWellness/index.jhtml?item=%2Fcommon%2FhealthAndWellness%2Fconditions%2Fdiabetes%2FinsulinProcess.html
Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes mellitus [Internet]. Waltham, MA: UpToDate Inc; [updated 2019 Jan 14; cited 2019 Feb 16]. Available from: https://www.uptodate.com/contents/glucagon-like-peptide-1-receptor-agonists-for-the-treatment-of-type-2-diabetes-mellitus
Britton C. Weight loss surgery changes the way our bodies sense food [press release]. (2019 Feb 5) [cited 2019 Feb 16]. Available from: https://www.mrl.ims.cam.ac.uk/blog/weight-loss-surgery-changes-the-way-our-bodies-sense-food/