The vagus nerve and digestion
HOW DOES THE VAGUS NERVE SUPPORT EVERY ASPECT OF DIGESTION?
Your digestive system depends upon the vagus nerve for proper function. Most every aspect of normal digestion, motility (movement of the food/stool) and nutrient absorption depends upon proper vagus nerve function. Without the vagus nerve functioning properly, food and stool does not pass through the intestines normally.
Your vagus nerve allows proper movement of food down your esophagus toward your stomach. This is called “peristalsis”.
Your vagus nerve triggers your stomach to produce a healthy amount of stomach acid for proper digestion of your food.
This valve sits at the base of the stomach and allows food to exit the stomach and move into the intestines. The vagus nerve triggers the opening of the pyloric valve so that food does not sit in the stomach longer than necessary.
The pancreas secretes pancreatic enzymes that assist in digestion and absorption of nutrients, especially fats and proteins. The pancreas is partially controlled by the parasympathetic fibers originating in the dorsal vagal nucleus and the ambiguous nucleus of the brain, then carried by the vagus nerve.
SPHINCTER OF ODDI
The vagus nerve stimulates the Sphincter of Oddi to open, allowing bile (from the gallbladder) and digestive enzymes (from the pancreas) to pass into the intestines.
The vagus nerve stimulates the intestines to push food (or “chime”) along the intestinal tract (“peristalsis”). Proper peristalsis mixes and shifts the chime, allowing proper nutrient absorption. Poor peristalsis can result in gastroparesis, constipation, bloating and discomfort. If partially digested food sits in the intestines without moving, the toxins and free radicals produced are absorbed by the body. The result can be chronic inflammation of the intestinal tract, resulting in poor nutrient absorption, discomfort or pain, and constipation (often alternating with diarrhea).
Inflammation of the gut can contribute to poor motility (and diarrhea). The vagus nerve is critical in controlling inflammation, both through its innervation with the spleen and its direct control of many inflammatory cells. The site on the inflammatory cell under control of the vagus nerve is called the alpha-7 subunit nicotinic acetylcholine receptor (α7nAChR). As the cholinergic anti-inflammatory pathway, it is dependent upon proper vagus nerve functioning.