Food intolerance is a condition in which a person has difficulty digesting certain foods. It occurs when the body has a negative reaction to a particular food but does not involve the immune system (unlike food allergies). This means that food intolerance is generally not life-threatening, although it can cause a range of uncomfortable symptoms.

The three most common food intolerances are:

• Lactose intolerance: This is the inability to digest lactose, a sugar found in milk and dairy products. It is caused by a deficiency in the enzyme lactase, which is needed to break down lactose in the small intestine. Symptoms may include bloating, gas, diarrhea, and abdominal pain.

• Gluten intolerance: This is sensitivity to gluten, a protein found in wheat, barley, and rye. It can cause a range of symptoms including diarrhea, bloating, abdominal pain, and fatigue. In severe cases, it may cause damage to the lining of the small intestine, known as celiac disease.

• Fructose intolerance: This is the inability to absorb fructose, a sugar found in many fruits, honey, and high-fructose corn syrup. Symptoms may include bloating, gas, abdominal pain, and diarrhea.

Symptoms of food intolerances:

Symptoms of food intolerances can vary depending on the individual and the type of intolerance but can include digestive symptoms such as bloating, gas, and abdominal pain, as well as skin symptoms, respiratory symptoms, headaches, fatigue, joint pain, and mood changes.

Food intolerances can cause a wide range of symptoms, which can vary depending on the individual and the type of food intolerance. Some common symptoms of food intolerances include:

1. Digestive symptoms: These can include bloating, gas, abdominal pain, diarrhea, constipation, and nausea.

2. Skin symptoms: Some people may experience skin symptoms such as rashes, hives, or itching.

3. Respiratory symptoms: Certain food intolerances can cause respiratory symptoms such as wheezing or coughing.

4. Headaches or migraines: Some people may experience headaches or migraines after consuming certain foods.

5. Fatigue: Food intolerances can sometimes cause fatigue or a general feeling of tiredness.

6. Joint pain: In some cases, food intolerances can cause joint pain or inflammation.

7. Mood changes: Food intolerances can sometimes cause mood changes such as irritability, anxiety, or depression.

Causes of Food Intolerance: 

Food intolerances are caused by a variety of factors, including:

• Enzyme Deficiencies: Many food intolerances are caused by the body's inability to produce or break down certain enzymes needed for digestion. For example, lactose intolerance is caused by a deficiency in lactase, the enzyme needed to break down lactose (a sugar found in milk).

• Sensitivity to Food Components: Some food intolerances are caused by sensitivity to certain components of food, such as gluten (a protein found in wheat, barley, and rye) or histamine (a compound found in fermented foods and aged cheeses).

• Gut Microbiome Imbalance: The gut microbiome, which is made up of trillions of microorganisms in the digestive system, plays an important role in digestion and immune function. An imbalance in the gut microbiome can lead to food intolerances and other digestive issues.

• Genetics: Some food intolerances have a genetic component, meaning they run in families. For example, celiac disease, which is an autoimmune disorder caused by an intolerance to gluten, has a genetic component.

• Other Health Conditions: Certain health conditions, such as inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS), can lead to food intolerances.

It's important to note that the causes of food intolerances can be complex and may involve multiple factors. If you suspect you have a food intolerance, it's best to speak with a healthcare professional to determine the underlying cause and develop an appropriate treatment plan.

Are intolerance blood tests worth it? 

First, it's important to note that food intolerance is a complex condition, and there are no definitive tests or diagnostic criteria for identifying food intolerances. This can make it challenging to accurately diagnose and treat food intolerances.

While food intolerance tests may be useful in identifying certain types of food intolerances, they are not always accurate or reliable. Some tests have been shown to have high false-positive rates, which means they may identify food intolerance when one does not exist. Additionally, the results of these tests may be influenced by other factors, such as recent diet changes, medication use, or underlying medical conditions.

Therefore, it's important to work with a healthcare professional who can interpret the results of an intolerance blood test in the context of your individual health history and symptoms. They may also recommend additional testing or an elimination diet to confirm or rule out suspected food intolerance.