Persistent taste sensations after eating are more often due to foods consumed during the meal. Remnants of food particles adhere to the surface of the tongue, palate, between the teeth and crevices of the oral cavity due to chewing and swallowing. When these food particles mix with saliva in the mouth, it may activate the taste buds and the taste sensation continues for a period of time. Certain foods are more likely to adhere to the rough surface of the tongue, especially if there is limited intake of fairly tasteless fluids, like water, during or after a meal. This may be more pronounced by foods like chocolate, especially bitter varieties, pine nuts, pickles and characteristically bitter vegetables like bitter gourd.
However, at times a person may experience an unusual taste sensation in the mouth after eating that is unrelated to the recently ingested foods. The tastes of concern in most cases are the bitter or sour taste. Sometimes an acidic taste in the mouth is often reported despite not eating any overtly acidic foods. Many of these cases can be attributed to acid reflux, which is more likely to arise after meals. However a disturbance in the taste sensation, known as dysgeusia may be due to various causes that need to be investigated. A bad taste in the mouth is known as cacogeusia. In both dysgeusia and cacogeusia, these unusual or offensive taste sensations may be unrelated to food or eating.
Food Stimulates Acid Secretion
There are various stages of acid secretion in response to food. The sight or even thought of food can elicit the acid secretion process in the stomach, well before any food is enters the mouth. This is more likely to occur when hungry or seeing or tasting foods that a person finds desirable. This is known as the cephalic phase of gastric acid secretion.
Once food is consumed and enters the stomach, the amount of digestive juices and stomach acid increases substantially. Both vasovagal (brain to stomach and back) and enteric plexus (local) reflexes maintain the gastric acid secretion at a peak rate until the stomach contents gradually exit to the stomach and pass into the duodenum. This is known as the gastric phase of gastric acid secretion.
As the stomach empties, the acid secretion does not stop but does reduce greatly compared to the gastric phase. The presence of food in the duodenum (first part of the small intestine) causes the duodenal mucosa to release the digestive hormone, gastrin, which stimulates the stomach to continue secreting acid. This is known as the intestinal phase of gastric acid secretion.
Gastric acid secretion can therefore commence even before food enters the mouth and persist for an hour or two, or even slightly longer, after eating. In some cases, it may be persisting for up to 3 hours or more, especially when eating a large meal or various causes of delayed gastric emptying and sluggish gastrointestinal motility.
Causes of Mouth Tastes After Meals, Food
Although acids trigger the sour taste sensation (refer to sense of taste), it can also be described as a bitter taste in the mouth. Acid reflux occurs when the acidic stomach contents flow backward up into the esophagus. This usually does not happen as the action of the lower esophageal sphincter (LES) prevents the stomach contents from emptying into the esophagus.
In acute acid reflux, the functioning of the lower esophageal sphincter may be temporarily disrupted due to the action of certain substances like alcohol. Other conditions may also allow for the stomach contents to rise into the esophagus, even with alcohol consumption. This includes :
- Exercise after eating
- Sleeping or lying flat after a large meal
- Pressure on the stomach, like with tight clothing, especially after eating
The reflux is temporary, and may present with typical symptoms such as heartburn, nausea and water brash (excessive accumulation of saliva in the mouth). However, it does not always present in such a typical manner and may just appear as indigestion, or in cases of silent acid reflux there are no symptoms of a gastrointestinal upset and just irritation in the throat or unusual tastes in the mouth. Sometimes bile may accompany the stomach acid as it enters the esophagus. This is known as bile reflux and bile is a very bitter substance.
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Gastroesophageal Reflux Disease
Gastroesophageal reflux disease (GERD) is a chronic condition that is commonly caused by LES dysfunction. Other causes like raised intra-abdominal pressure due to pregnancy or obesity, delayed gastric emptying or a hiatal hernia may also play a role in GERD.
Although less common, other causes of a bitter taste in the mouth may not be involved. In these cases, pus, blood and mucus may cause the bitter taste sensation that may be more pronounced after eating.
- Tooth cavity
- Mouth sores and ulcers
- Allergic naso-respiratory conditions like allergic rhinitis or asthma
- Acute sinusitis
- Abscess in the mouth, throat, sinus or upper respiratory tract
- Salivary gland infections like bacterial parotitis
- Neurological causes often involving the facial nerve (CN VII) – paresthesia
- Metabolic conditions like changes in blood glucose levels and breakdown of fats may also cause unusual tastes in the mouth, as is seen with diabetes mellitus (sugar diabetes)