Glucose balance in the body is a complex dance involving several key players such as Insulin, glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), amylin, dipeptidyl peptidase 4 (DPP-4) and more.
Pancreatic beta cells produce Insulin and amylin. Both Insulin and Amylin get secreted together. Amylin can affect sugar balance through multiple mechanisms, including:
Slowing down gastric emptying
Decreasing glucagon release
Reducing hunger
L cells of the small intestine produce Glucagon-like peptide-1 (GLP-1). GLP-1 binds to GLP-1 receptors found in various tissues, including pancreatic beta cells, pancreatic ducts, gastric mucosa, kidney, heart, skin, immune cells, and the hypothalamus. GLP-1 has several functions:
Stimulates glucose-dependent insulin release from pancreatic islets
Slows down stomach emptying
Prevents inappropriate post-meal glucagon release
Decreases appetite
K cells of the small intestine produce Glucose-dependent insulinotropic polypeptide (GIP). GIP binds to GIP receptors in pancreatic beta and alpha cells, subcutaneous visceral and adipose tissue, bone, and heart. GIP gets secreted along with GLP-1. Together they act to stimulate insulin secretion. However, GIP does not affect gastric emptying.
Dipeptidyl peptidase 4 is an enzyme found on the surface of most cell types. It deactivated several bioactive peptides, including GLP-1 and GIP.
Recently, there have been several new drugs on the market for both diabetes and obesity that act as GLP-1 agonists. There have been some concerns about the risk of thyroid cancer, but we don’t have much data yet.
In a new study published in the Diabetes Care journal, researchers did a case-control analysis of data from France’s national health care insurance system database. They included patients with type 2 diabetes who were on GLP-1, DPP-IV inhibitors, metformin, sulfonylureas, repaglinide, alpha-glucosidase inhibitors, or thiazolidinediones. The time frame for the data collection was 2006-2018. New cases of thyroid cancer from 2014 to 2018 were included in the study.
The study included 3,746,672 people with type 2 diabetes. 4,466 patients developed thyroid cancer during the study time frame. After excluding patients with a history of cancer, they analyzed data from 2,562 adults and matched them with 45,184 controls without thyroid cancer.
The researchers found that those patients currently using a GLP-1 receptor agonist had a 46% higher risk of thyroid cancer than those not using it. Patients using GLP-1 agonists for 1-3 years had a 58% higher risk of thyroid cancer. Lastly, patients using GLP-1 agonists for more than three years had a 36% higher risk for thyroid cancer.
The bottom line is that doctors and patients should be aware of the potential risk for thyroid cancer with GLP-1. We should not look at them as a magic bullet that replaces lifestyle medicine but used as a tool in select cases with proper guidance.
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