Sugar is found in many parts of our diets, both in natural and manufactured foods. True allergy to sugar does not exist, but sugar intolerances do, which can result in adverse reactions.

Cells in the body use sugar for energy, so an adverse reaction to sugar can cause serious complications. There are steps that people can take to avoid sugar and the complications of intolerance, and seeing a doctor is always recommended.

Fast facts on allergies

  • The symptoms of an allergy may vary from person to person.
  • A severe allergy to something mixed in with sugar-containing foods can be cause for concern due to anaphylaxis.
  • Sugar intolerance to certain sugars is not a true allergy.
  • A person with a food allergy or intolerance will often manage it by keeping a food journal.
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An allergy can be confused with intolerance, but there are some distinct signs and symptoms.

Symptoms of a food allergy vary from person to person and can even change depending on the type of food consumed.

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Symptoms such as clogged sinuses, headaches, and hives may indicate an allergic reaction.

People who are allergic to certain components within food tend to experience symptoms after consuming them.

Symptoms include:

  • clogged sinuses
  • headaches
  • stuffy or a runny nose
  • stomach cramps
  • redness of the skin
  • rashes or hives
  • nausea or vomiting

Severe allergies can cause a serious reaction known as anaphylaxis. These reactions can come on quickly and may be fatal if left untreated. Symptoms of a severe anaphylactic response to an allergen can include:

  • swelling of the lips, mouth, tongue, or throat
  • shortness of breath or being unable to breathe properly
  • a wheezing cough
  • a sudden drop in blood pressure
  • a racing heart
  • dizziness or loss of consciousness

People with severe allergies should carry antihistamine medications or epinephrine pens on them at all times.

Anyone who experiences new signs of an allergic reaction should contact their doctor or allergist. Symptoms of anaphylaxis require medical attention immediately, even if the person has already taken antihistamine medication or used epinephrine.

People who experience signs of an allergy or intolerance for the first time should also visit a doctor to discuss their options.

A true allergy to sugar in itself is for the most part non-existent, whereas some sugar intolerances are quite common. The two are similar but have some key differences.

Food allergy

An allergy develops when the body responds to a component of something mixed in with sugar as if it were an intruder rather than food.

The body responds to the allergen by triggering the immune system to attack and eliminate the invader. During an allergic reaction, the immune system releases histamine, which causes many of the symptoms experienced during an allergic reaction.

Sugar intolerance

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Symptoms such as abdominal cramps and painful bloating can indicate a food intolerance.

Sugar intolerance does not involve the immune system response that occurs with an allergy. Instead, someone who is intolerant of a certain sugar has trouble digesting or processing it.

Sugar intolerance is relatively common. It causes a range of digestive issues, which vary in severity from person to person. As the body tries to digest the sugar, people may experience symptoms a few minutes to several hours after eating the sugar.

Symptoms of sugar intolerances often include:

The symptoms of sugar intolerance often follow a pattern whereby the person may feel nausea or cramps first, followed by gas and bloating as the sugar passes through the digestive system.

Sometimes a person will experience diarrhea as the sugar exits the body, but this is likely to stop once the person has stopped eating the sugar that bothers them. Those who are intolerant to sugar may also show signs of restlessness or inattention.

One typical example of sugar intolerance is lactose intolerance. According to the National Institutes of Health (NIH), up to 65 percent of people around the world experience some level of lactose intolerance.

Someone who is lactose intolerant will have trouble digesting lactose, which is the sugar found in milk. This intolerance causes one or more of the digestive issues noted.

People with certain ethnic backgrounds are more likely to be intolerant to lactose, including those who are:

  • West African
  • Arab
  • Jewish
  • Greek
  • Italian
  • East Asian

Some people with other digestive issues, such as irritable bowel syndrome (IBS), celiac disease, and functional gastrointestinal disorders (FGD) may also have difficulty digesting certain sugars, such as fructose and lactose.

Intolerance to specific sugars may cause other problems as well. Someone who is intolerant to glucose may also have prediabetes or type 2 diabetes. Others who are intolerant to fructose may be at risk for kidney failure.

Food allergies or intolerances can cause life-threatening complications, which is why people who experience serious food allergies should carry medication with them at all times. Because sugar is the primary source of energy for cells, people who have food allergies or intolerance to certain sugar types will need to find other ways to fuel their body.

Keeping a log of everything that they eat throughout the day can help a person discover what type of sugar is causing the intolerance. People can then eliminate these trigger foods from their diet.

Someone with a food allergy to something mixed in with sugar may need to remove all forms of this food from the diet to avoid reactions. Additionally, if intolerance to sugar occurs, people need to avoid foods containing that particular sugar.

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People with a sugar intolerance should be mindful of the ingredients in juices, soft drinks, and other potentially sugary drinks.

People may have intolerances to both natural and processed forms of sugar, which can be found in the following:

  • fruits and fruit juices
  • milk
  • soft drinks and sweetened coffee or tea
  • condiments, such as ketchup, syrup, and jelly
  • desserts and baked goods, such as cakes, cookies, muffins, ice cream, and candy
  • breakfast cereals, protein bars, and granola bars
  • nut butter and nut milk

Hidden sugars

Certain unexpected snacks and food items also contain sugars, such as pasta sauces, chips, and salad dressings. It is important that people with problems with sugar read the labels of everything they eat to avoid potential reactions. People should also read food labels carefully because sugar and other sweeteners have many different names.

The names of some of these sweeteners include:

  • sugar, brown sugar, glucose cane syrup, cane juice, or beet sugar
  • corn syrup, high fructose corn syrup, or fructose
  • agave
  • molasses
  • honey
  • ice syrup

Many people who are intolerant to a specific type of sugar may not have an adverse reaction to certain sugar substitutes. These sugar substitutes can include:

  • xylitol
  • stevia
  • saccharin
  • aspartame

However, sugar substitutes may have health implications that people should be aware of as well. Research posted in Nature suggests that artificial sweeteners could play a role in developing glucose intolerance, so they may not be a good choice in many cases.

True allergy to sugar does not exist, but sugar intolerances do. Anyone experiencing new symptoms to certain foods should see their doctor or allergist to check for allergies and intolerances. Doctors can carry out blood tests and breath tests to identify many sugar intolerances, and there are also different types of tests available for diagnosing food allergies.

The doctor may ask people to help the process by following an elimination diet or keeping a food diary. Working directly with a doctor is the best way to find a solution to most cases of sugar intolerance or other food allergies.