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Lactose Intolerance & Other Common Food Intolerances
Updated on January 4, 2023
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Lactose Intolerance & Other Common Food Intolerances
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A food intolerance (also known as food sensitivity) is when you have difficulty digesting certain foods. Eating these foods usually cause unpleasant symptoms, including:

  • Itching
  • Stomach pain
  • Diarrhea
  • Bloating and gas
  • Skin rashes

If you have signs of food intolerance, you should avoid foods that are bad for your gut. It prevents your symptoms from getting worse while you’re recovering.

Food intolerance symptoms typically appear within hours after your last meal. A person can have an intolerance or sensitivity to different foods, like soy and fennel.

At-home food sensitivity tests can help you find out which foods you might react to. Below is a list of the common food intolerances to watch out for.

1. Lactose Intolerance

Milk and other dairy products contain a sugar called lactose. Our bodies need the enzyme lactase to break it down for digestion.

Babies usually produce enough lactase to digest milk, including breastmilk. This would explain why lactose intolerance is less common in young children. 

Many people stop producing the enzyme when they’re 2 to 5 years old. It causes them to develop an intolerance to foods containing lactose.

Lactose intolerance is common in the United States. It affects about 30 million Americans by the age of 20. It’s also more common in mixed Americans, including:

  • Asian Americans
  • African Americans
  • Mexican Americans
  • Native Americans

Signs of Lactose Intolerance

People who are intolerant to lactose will exhibit similar signs as other food intolerances:

  • Abdominal cramps
  • Bloating
  • Diarrhea
  • Gas
  • Nausea
  • Stomach upset

How severe your symptoms are depends on the amount of lactose you consume and how much lactase your body makes.

The greater the difference, the more difficult it is for your body to digest lactose. This leads to worse symptoms.

Is There A Test for Lactose Intolerance?

Symptoms alone are not enough to diagnose lactose intolerance. Your doctor may ask you to avoid milk and dairy products to see if your condition improves.

To confirm your diagnosis, they might order a lactose intolerance test. It involves drinking lactose after an 8-hour fast and seeing how your body reacts. 

There will be blood tests in the next 2 hours to measure your blood glucose. If your blood sugar levels remain unaffected, you may have lactose intolerance.

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2. Gluten Intolerance

Gluten is a type of protein found in various grains and grain products. These include:

  • Wheat
  • Barley
  • Rhye
  • Cereal
  • Beer
  • Pasta
  • Rice
  • Breads

Some people react to the gluten in these foods. This is known as gluten intolerance or non-celiac gluten sensitivity (NCGS). 

Gluten sensitivity is not the same as Celiac disease. The latter causes an autoimmune response to gluten, similar to food allergies. A food intolerance is a digestive reaction to a particular food.

Researchers believe that about 6% of Americans have gluten intolerance, compared to only 1% who have Celiac disease. That’s about 19.77 million of the current U.S. population.

Signs of Gluten Intolerance

People with this food intolerance may feel sick when they eat gluten. They may experience:

  • Abdominal pain
  • Anxiety
  • Bloating
  • Depressive symptoms
  • Difficulty concentrating
  • Fatigue
  • Headaches
  • Joint pain
  • Nausea
  • Skin rashes
  • Vomiting

Symptoms can last anywhere from a few hours to days after eating foods that contain gluten.

How to Test for Gluten Intolerance

Your doctor will ask you to eat gluten-rich foods for 6 weeks. While on a gluten diet, they’ll perform a skin prick test and blood tests to see if you have wheat allergies or celiac disease.

If you don’t have these conditions, the doctor will place you on an elimination diet for another 6 weeks. You can’t eat gluten during this time. You also have to keep track of your symptoms.

People who show improvements will be asked to slowly re-introduce gluten into their diet. If symptoms return, this means you are gluten intolerant.

3. Histamine Intolerance

The body produces dietary histamine when it encounters a food allergen. Food allergens are harmless food mistakenly perceived by your immune system as a threat.

Some common food allergens that can trigger the release of histamines are:

  • Eggs
  • Fish
  • Milk
  • Peanuts
  • Shellfish
  • Soybeans
  • Tree nuts
  • Wheat

A person may not immediately show signs. But as you eat more allergenic foods, the histamines will build up. Histamine intolerance develops when there’s too much of it in the body.

It is estimated that 1% of Americans (about 3.3 million) have histamine intolerance.

Signs of Histamine Intolerance

Histamine intolerance may produce similar symptoms as food allergies. These include:

  • Asthma
  • Coughing
  • Diarrhea
  • Fatigue
  • Flushed skin
  • Headache
  • Heartburn
  • Hot flashes
  • Irregular heartbeat
  • Low blood pressure
  • Nausea
  • Red itchy bumps (hives)
  • Runny or stuffy nose
  • Skin itching
  • Sneezing
  • Watery eyes

A food allergy is not the same as histamine intolerance, however. Food allergy symptoms appear within minutes of eating.

If you have histamine intolerance, you may not show signs until a few days or weeks after your first exposure to a food allergen. Your symptoms can also last for weeks.

How to Test for Histamine Intolerance

Doctors will first try to rule out allergies and common food sensitivities. If you test negative for these conditions, they can check for histamine intolerance.

To do this, they will measure your histamine and diamine oxidase. People with histamine sensitivity lack diamine oxidase.

Your doctor will then place you on a low-histamine diet. After 4 weeks, they will measure your levels to see if they have improved. If they did, it suggests you have histamine intolerance. 

4. Caffeine Intolerance

Caffeine is coffee’s most popular ingredient. But you can also find it in other beverages and food products like tea, soda, energy drinks, and chocolate.

It is known for its stimulant properties, such as its ability to boost energy and enhance focus. Unfortunately, some people have a sensitivity or intolerance to caffeine.

Most people can safely consume up to 400 mg of caffeine daily. A person with caffeine sensitivity will experience negative side effects when exposed to small amounts.

The risk for caffeine intolerance increases with age. If you have this condition, you can go for decaf. Decaffeinated coffee has health benefits, just like regular coffee. 

Caffeine Intolerance Symptoms

The signs of caffeine sensitivity are similar to an overdose. It can cause:

  • Anxiety
  • Diarrhea
  • Dizziness
  • Fast heart rate
  • Headaches
  • Insomnia
  • Irritability
  • Muscle tremors
  • Nausea
  • Restlessness
  • Shaking
  • Unusual heart rhythm

These symptoms usually appear within minutes of consuming caffeine.

How to Test for Intolerance to Caffeine

Doctors have not yet figured out how to test for caffeine intolerance. But there are at-home health kits that can help determine if you have one. 

5. Alcohol Intolerance

Alcohol is an ingredient found in beer, wine, liquor, and spirits. It’s both a sedative and a depressant that can relax you and improve your mood after 1 to 2 glasses.

Some people are unable to digest alcohol. This is a genetic metabolic disorder known as alcohol sensitivity. A person who has it lacks the digestive enzymes to break it down.

According to one study, 66 out of 948 people said they had wine intolerance.

Alcohol Intolerance Symptoms

Alcohol intolerance causes unpleasant symptoms with just a small amount of alcohol. 

The most common of which is called an alcohol flush. It’s when your face, neck, or chest turns pink or red. These areas may also feel warm.

Other signs and symptoms of alcohol sensitivity are:

  • Diarrhea
  • Nausea
  • Vomiting

If you get rashes, skin itching, swelling, and severe stomach ache — you may have an alcohol allergy and not an intolerance. You need to see a doctor right away.

How to Test for Alcohol Intolerance

Your doctor may initially run skin tests and blood tests. They will see if you’re allergic to other ingredients in alcoholic drinks, such as grains and hops.

Once they rule out food allergies, they might use the ethanol patch test. It checks your skin for reactions to ethanol, the main compound of alcohol.

Benefits of Probiotics on Food Intolerances

Having a food intolerance can be very uncomfortable. It causes a range of unpleasant symptoms, so you never get to enjoy eating certain foods.

Food intolerances also have an impact on your health. It prevents your digestive system from processing foods. You can’t digest or absorb the nutrients of foods you’re intolerant to.

Probiotics are proven to help with food allergies. They might be able to relieve any digestive symptoms caused by food intolerance.

The best probiotic supplements balance your gut bacteria. A balanced gut microbiome makes it easier for your body to digest foods and use their nutrients. It can:

  • Support your immune system
  • Protect you against infections
  • Regulate your mood
  • Balance your hormones
  • Improve your overall health

Besides taking probiotics, you should eat foods that are good for your gut. This keeps your digestive tract healthy and functioning properly.

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Updated on January 4, 2023
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8 sources cited
Updated on January 4, 2023
  1. Lactose intolerance.” MedlinePlus.

  2. Lactose Intolerance May Not Be As Common As We Thought.” The University of Alabama at Birmingham.

  3. Gluten Intolerance.” Cleveland Clinic.

  4. Histamine and histamine intolerance.” PubMed.

  5. Food allergy vs. food intolerance: What's the difference?” Mayo Clinic.

  6. Histamine and histamine intolerance.” The American Journal of Clinical Nutrition. 

  7. Alcohol intolerance.” Mayo Clinic.

  8. Alcohol intolerance.” Cleveland Clinic.

Ada Sandoval
Ada Sandoval
Content Contributor
Ada Sandoval is a B.S. in Nursing graduate and a registered nurse with a heart for abandoned animals. She works as a content writer who specializes in medical-related articles and pet health.
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