Food intolerance occurs when a person has trouble digesting particular foods. It may happen due to the absence of an enzyme responsible for the digestion of certain foods. The condition may also be triggered by sensitivity to food additives and gastrointestinal disorders like Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), and Celiac disease. In this article, we have listed the important details that an individual needs to know about food intolerance.

Common types of food intolerances
Food intolerance occurs when the body lacks digestive enzymes. The intolerance may be triggered if the body is sensitive to certain chemicals. Here are the common types of food intolerances which may lead to digestive issues.

• Fructose intolerance
  Sweeteners like honey, certain vegetables, and fruits are foods that contain fructose. The lack of an enzyme responsible for digestion may lead to fructose malabsorption. The poorly absorbed fructose travels to the large intestine, is fermented by bacteria, and causes digestive stress.
• Lactose intolerance
  When people don’t make sufficient lactase enzymes, their body fails to break down lactose. The lack of lactose absorption may cause uneasiness in the digestive system. Lactose is present in milk and other dairy products.
• Gluten intolerance
  Gluten is a protein found in foods including barley, rye, and wheat. Gluten intolerance occurs when the body finds it difficult to digest gluten. Gluten intolerance (also known as non-celiac gluten sensitivity) must not be confused with celiac disease, an autoimmune disease that damages the small intestines when a person eats gluten-rich foods.
• Histamine intolerance
  Histamines are produced by bacteria when foods need to be stored and fermented. The chemical promotes immune health by protecting the body from allergens. Furthermore, histamine can be metabolized and excreted easily. But some people may find that the enzymes responsible for breaking it down, diamine oxidase and N-methyltransferase, do not function properly. The phenomenon may lead to intolerance toward histamine.

Other food intolerances include caffeine, salicylate, fermentable oligo-, di-, monosaccharides and polyols (FODMAPs), and sulfite intolerance.

Symptoms of food intolerance
The symptoms of food intolerance differ based on the type of food that disagrees with an individual’s digestive system. The most common symptoms of food intolerance are heartburn, nausea, an upset stomach, headaches, migraines, and pain in the abdominal region. Food intolerance may also lead to symptoms like diarrhea, gas, bloating, rashes on the skin, and flushed skin.

Food allergies vs. food intolerances
People often confuse food allergies with food intolerances because the signs and symptoms are pretty similar. However, food intolerance generally affects the digestive system and is less threatening. On the contrary, a food allergy can damage the immune system. Therefore, a person who is allergic to certain foods may experience several symptoms, which may also threaten their life.

Diagnosis
The thin line between the symptoms of food allergies and food intolerances makes it tricky to diagnose the exact condition. Diagnosis may also be challenging if a person is intolerant to several foods. Furthermore, food intolerances also have similar symptoms to chronic digestive conditions like IBD and IBS. However, identifying a few patterns can help a healthcare expert distinguish and identify the precise disorder.

Maintaining a diary
A healthcare expert may ask the patient to maintain a diary to document the foods they eat, the symptoms they notice, and the timings. The information recorded in these diaries can help the expert identify the foods responsible for the intolerance.

An elimination meal plan
In this case, the patient is advised to exclude several potential foods from their meals that may cause intolerance. These foods may be introduced to meals later when the healthcare expert tests for symptoms.

Skin prick test
Healthcare providers conduct the test to rule out potential food allergies. The test involves placing a small amount of food on the patient’s back or forearm. The skin is then poked with a needle to check if there is an allergic reaction.

Blood test
A blood test can also help differentiate between an allergy and an intolerance. The diagnosis is conducted by measuring immunoglobulin E (IgE) antibody levels. High levels of these antibodies may indicate an allergy.

A hydrogen breath test
The test is helpful when it comes to detecting lactose intolerance. In a hydrogen breath test, the patient is asked to drink a liquid with lactose. For the next few hours, they must breathe into a balloon-like container every 30 minutes for a few hours. If the individual is lactose, the levels of hydrogen in their breath will be significantly high.

Treatment
A diagnosis may help identify the possibility of food intolerance. However, there is no cure for the condition. The best way to avoid the symptoms of food intolerance is to avoid the foods that make them intolerant. Healthcare providers may also recommend supplements to help with digestion.