Introduction

Food sensitivities and intolerances are common, and their number seems to be increasing. Up to 20% of the world's population is thought to suffer from food intolerance, according to one study. The study, "The Differential Diagnosis of Food Intolerances," was published in the Deutsches Aerzteblatt International in May 2009.

Due to the wide range of symptoms, the diagnosis of food intolerances can be difficult and is often confused with gastrointestinal disorders. Here is an overview of the most common forms of food intolerances, their symptoms, and foods to avoid.

What is a Stomach Bug?

A gastrointestinal infection is an intestinal infection characterised by watery diarrhea, stomach cramps, nausea or vomiting, and in rare cases, fever. The causative agent may be a virus, a bacterium, or a parasite.

Contact with an infected person or consumption of contaminated food or water are the most common ways to contract a gastrointestinal infection, also called gastroenteritis. Healthy people can recover without problems.

However, gastrointestinal infections, especially viral infections, can be fatal to newborns, the elderly, and those with weakened immune systems. Since there is no cure for viral gastroenteritis, prevention is key. Avoid contaminated food and water, and wash your hands frequently and thoroughly.

What is food intolerance?

Food intolerance is sometimes misunderstood as gastrointestinal virus. Another term used in the same context is food allergy. Although some symptoms are similar, food intolerance is different from food allergy.

In food intolerance, symptoms usually appear within a few hours of eating the intolerant food. However, it can take up to 48 hours for symptoms to appear, and they can last for hours or even days. This is according to the study "Food intolerances and eosinophilic esophagitis in childhood," published in Springer Link in 2009.

Stomach upset can also result from a deficiency of certain enzymes in the digestive system. Food intolerances indicate an exacerbation of gastrointestinal disorders such as celiac disease, Crohn's disease, ulcerative colitis and inflammatory bowel disease (IBD). It can be difficult to associate symptoms with a specific food if the intolerant foods are consumed regularly.

Food intolerances can cause a variety of symptoms, with the skin, digestive system, and respiratory system most commonly affected. Common symptoms of stomach upset include abdominal pain, diarrhea, bloating, headaches, migraines, heartburn, nausea and upset stomach.

 

Food intolerance vs. gastrointestinal virus

Food intolerance may be due to lactose intolerance and a deficiency of enzymes needed to digest proteins in food. Intolerance to chemical additives that produce color, enhance flavor, and prevent the development of microorganisms is common. Various dyes and monosodium glutamate (MSG), a flavor enhancer, are causative components.

After eating certain foods or drinks, food intolerance can cause stomach upset and other digestive problems. However, most people with food intolerances can consume tiny amounts of such products without experiencing unpleasant side effects.

Bacteria, parasites, toxins, and viruses can all be the cause of an upset stomach. However, the most common cause is viruses. Adults are often infected with norovirus, while children are infected with rotavirus. These viruses attack the lining of the small intestine.

Diarrhea is the most common symptom of gastroenteritis. Other symptoms include pain or cramping in the abdomen, nausea, vomiting, fever, body aches and headache. Fever is a sign that your body is trying to fight off gastroenteritis. You may have sweating, chills, headache or aching limbs.

A stool examination or sigmoidoscopy is helpful in diagnosing bacteria, viruses, and parasites responsible for a stomach bug. 

Rest and hydration are important to feel better quickly. If the stomach is still unsettled, small amounts of water, juice or broth can be sipped frequently or chewed on ice cubes. It's important to know that in cases of severe diarrhea, water alone isn't enough to maintain fluid balance. In such cases, hydration along with electrolyte supplementation is essential.

Treatment of food intolerances consists of avoiding or minimizing the consumption of certain foods and treating symptoms by taking an antacid for heartburn or stomach pain.

Elimination diets to narrow down the intolerant foods or other testing procedures are useful in identifying food intolerances.

Elimination diets are the subject of research. The study, "Restriction and Elimination Diets in ADHD Treatment," was published in October 2014 in the Child and Adolescent Psychiatric Clinics of North America.

In elimination diets, foods typically associated with intolerances are excluded for a short period of time or until symptoms disappear. Then, the foods are gradually reintroduced while monitoring the symptoms of food intolerance. This diet helps determine which foods are causing the symptoms.

 

Food intolerance vs. food allergy

After eating certain foods or drinks, a food intolerance can cause stomach upset and other digestive problems. An intolerance to a food is not the same as an allergy to a food. Food allergies trigger a life-threatening reaction from the immune system.

Most people with food intolerances can consume tiny amounts of such foods without experiencing unpleasant side effects. An elimination diet and food diary can help determine if you have a food intolerance.

 

Common types of food intolerances

The following food intolerances are the most common:

Lactose

Lactose is a sugar found in dairy products such as milk. Lactose is broken down in the body by an enzyme called lactase, which is necessary for normal digestion and absorption. Lactose intolerance is due to a deficiency of lactase enzymes that prevents the digestion of lactose, resulting in digestive symptoms.

Diarrhea, bloating and flatulence are the digestive symptoms of lactose intolerance. The study, "Lactose intolerance: diagnosis, genetic and clinical factors," was published in Clinical and Experimental Gastroenterology in March 2012.

 

Gluten

Gluten is a term that refers to proteins found in grains such as wheat, barley, rye, and triticale. Wheat allergies and celiac disease are misunderstood because of their similar symptoms.

A gluten-free diet is used to treat celiac disease and non-celiac gluten sensitivity. It involves avoiding meals and items containing gluten on a daily basis. Gluten intolerance can cause a variety of symptoms, including stomach upset, bloating and headaches.

 

Caffeine

Caffeine is a bitter substance found in coffee, soda, tea, and energy drinks. It's a stimulant, meaning that when you take it, you feel less tired and are more alert.

Caffeine is absorbed by most people without harmful effects.

However, some people are more sensitive to caffeine and show negative reactions to even small amounts. Caffeine hypersensitivity is related to genetics and a decreased ability to metabolize and excrete caffeine.

The study, titled ""No thanks, coffee keeps me awake": Individual Caffeine Sensitivity Depends on ADORA2A Genotype," was published in July 2012 in the journal Sleep.

People with caffeine hypersensitivity can suffer from symptoms such as anxiety, heart palpitations and insomnia after consuming even a tiny amount of caffeine. Caffeine-sensitive people should limit their consumption of caffeinated beverages.

 

Amines

Amines are formed by bacteria during the storage and fermentation of food. Although there are many other forms of amines, histamine is most commonly associated with food intolerances. Histamine protects the body from infection by triggering an inflammatory response in response to allergens.

The most common cause of histamine intolerance is altered activity of the enzymes responsible for histamine breakdown. The study, "Histamine and histamine intolerance," was published in the Clinical Journal of American Nutrition in May 2007.

Most people digest and absorb these substances well. However, some fail to break down histamine sufficiently, causing it to accumulate in the body.

 

Sulfites

Sulfites are compounds used as preservatives in foods, beverages, and some medicines. Some foods, such as grapes and aged cheeses, naturally contain them. Sulfites in foods and beverages are tolerated by most people. People with asthma are more likely to be sensitive to sulfites, although people without asthma may also have an intolerance.

According to one study, hives, swelling, a stuffy nose, redness of the skin, diarrhea, wheezing and coughing are common signs of sulfite sensitivity. The study, titled "Adverse reactions to the sulfite additives," was published in Gastroenterology and Hepatology from Bed to Bench in 2018.

In asthmatics with sulfite sensitivity, sulfites can cause airway constriction and, in severe cases, life-threatening reactions. Many foods and food additives are intolerable to certain people. Food dyes, eggs, aspartame, and sugar alcohols may be among the food incompatibles.

 

Conclusion

Food intolerances are not the same as indigestion. Most food intolerances do not activate the immune system, and their symptoms are generally milder. They can affect health and require medical intervention. A gastrointestinal infection, on the other hand, has more severe symptoms, but they are shorter in duration. Gastrointestinal infections require medical intervention and therapy in most cases.

Dairy products, caffeine, and gluten are all foods that people are intolerant to.

If you suspect a food intolerance, talk to your doctor or a dietitian about testing and treatment options. Food intolerances are less of a concern than gastrointestinal disorders, but they can significantly affect your quality of life.

 

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