Everybody experiences vomiting at one time or another in their lives. Although unpleasant, vomiting is a part of the body’s natural defense mechanism that is aimed at eliminating ingested harmful substances from the upper gastrointestinal tract. Vomiting may either occur immediately or sometimes after the consumption of harmful or irritant foods. If the upper digestive tract is irritated or inflamed, then food can trigger vomiting even if it is not an irritant substance.
Repeated bouts of vomiting that occur each time one eats something can deplete the body of essential nutrients and cause serious health issues. In some cases, serious complications may arise within a few days, and the condition may be life-threatening. Therefore, it is imperative to quickly identify the cause of vomiting that occurs after a meal, so that steps can be taken to avoid serious complications.
Read more about vomiting up water.
Mechanism of Vomiting
Vomiting is a key defense mechanism of the body. This process aims to quickly get rid of any toxic or harmful substance that is ingested. In the absence of a vomiting reflex, harmful substances may get absorbed into the blood and cause widespread tissue damage or disease within the body.
The process of vomiting involves a reflex action that is controlled by a region in the brain known as the vomit center. When stimulated, the vomit center sends nerve impulses to the muscles of the upper gastrointestinal tract. Upon nervous stimulation, the muscles of the esophagus, stomach and the upper part of the small intestine contract forcefully in a coordinated way to expel the contents of the stomach through the mouth. This reverse movement of stomach contents is known as anti-peristalsis because it occurs in a direction that is opposite to the peristaltic movements in the upper gastrointestinal tract.
Vomiting is a forceful expulsion of the stomach contents. Very strong anti-peristaltic movements in the upper gastrointestinal tract can lead to projectile vomiting. Vomiting should not be confused with the process of regurgitation, which is not as forceful. Unlike vomiting, regurgitation does not involve the upper part of the small intestine.
Nausea vs Vomiting
Nausea and vomiting frequently occur together. However, they are two different phenomena. Nausea refers to the unpleasant feeling of an impending vomiting episode. However, it may or may not be followed by actual vomiting. When vomiting does occur, the feeling of nausea usually subsides. However, in some cases, the feeling of nausea may persist even after a vomiting episode. It is also possible for vomiting to occur without any preceding feelings of nausea.
Both nausea and vomiting are controlled by closely related brain areas. The chemoreceptor trigger zone (abbreviated as CTZ) in the brain can indirectly stimulate the vomiting center in the brain. Substances such as hormones and drugs in the bloodstream can stimulate the chemoreceptor trigger zone. The vomiting center can also be stimulated directly. Nausea and vomiting can be triggered even when there is no food in the stomach. Brain injury, liver disease, and kidney diseases often trigger nausea and vomiting without any gastrointestinal irritation.
Causes of Vomiting After Eating
Vomiting after eating could occur due to the following reasons:
- The digestive tract may get irritated or inflamed after consumption of certain foods.
- Substances in the bloodstream may stimulate the vomit center or chemoreceptor trigger zone in the brain.
- Downward peristaltic movement of food may be prevented due to some obstruction in the gastrointestinal tract.
- Certain foods may cause aggravation of underlying conditions that cause nausea and vomiting.
Read more about sudden vomiting.
Food poisoning and gastroenteritis
Food poisoning and gastroenteritis are infectious diseases caused by the consumption of food or water that is contaminated with pathogenic bacteria or viruses. These are the most common causes of acute vomiting after consumption of food. Gastroenteritis is a viral infection of the gastrointestinal tract, and is characterized by diarrhea, abdominal cramps, nausea and vomiting.
Gastroenteritis can be easily transmitted from an infected person to a healthy person. This often causes gastroenteritis outbreaks. Vomiting and diarrhea are usually more intense during the first couple of days after the onset of gastroenteritis. Vomiting may subside earlier than diarrhea. Fever may also occur during this condition. Due to severe vomiting and diarrhea, there is always a risk of dehydration during gastroenteritis.
Food poisoning has similar symptoms to gastroenteritis, and is caused by consumption of food or water that is contaminated with pathogenic bacteria, viruses, parasites, or toxins.
Hormonal disturbances can cause vomiting even without consumption of food. However, having a meal may intensify the feelings of nausea that leads to vomiting. Changes in hormone levels in the blood can stimulate the vomit center and chemoreceptor trigger zone in the brain. A common example of hormonal disturbance that can lead to nausea and vomiting is morning sickness in pregnant women. Vomiting may also be triggered by hormonal changes caused by severe premenstrual syndrome and emergency contraceptive pills.
Severe pain is capable of causing nausea and vomiting. Some of the conditions that are characterized by severe pain include kidney stones, migraine, and severe headaches. People usually take painkillers to treat these extremely painful conditions. However, strong painkiller drugs (such as opioids) may also cause nausea as a side effect.
Food allergy and food intolerance
Some people are not be able to consume certain foods due to food allergies and food intolerance. Food allergies trigger an abnormal immune response in the body after consumption of foods that contain an allergen. Food intolerance is caused by a lack of certain digestive enzymes that makes it difficult to digest certain kinds of foods. Nausea and vomiting may occur in both food allergies and food intolerance. Nausea and vomiting may also occur in normal individuals upon consumption of oily meals and unpalatable foods.
Nausea and vomiting after consumption of food may also occur in cases where the gastrointestinal tract is blocked and food cannot move down the gut. Obstructions in the digestive tract may be caused by tumors, strictures, hernia, and twisting of bowels. Diarrhea, constipation, and reduced flatulence may also occur in such conditions.
Alcohol and drugs
Vomiting after eating can also be caused by alcohol and illicit drugs. Poisons may also induce vomiting after ingestion. These substances can cause vomiting by irritating the digestive tract, and stimulating the vomit center and chemoreceptor trigger zone in the brain. Chemotherapeutic drugs used to treat cancer, non-steroidal anti-inflammatory drugs (commonly abbreviated as NSAIDs), and some antibiotics can also trigger nausea and vomiting.
Nausea and vomiting can occur in certain strained psychological states such as anxiety, shock, and eating disorders (such as bulimia and anorexia nervosa). Forced eating in such conditions may trigger vomiting although in conditions like bulimia there is usually purging by inducing vomiting after meals.
Vomiting after eating can also be caused by a variety of systemic conditions that do not affect the gastrointestinal tract directly. Examples of such systemic causes include hepatic failure, pancreatitis, diabetic ketoacidosis, renal failure, gallbladder disease, Addison’s disease and traumatic brain injury.