Sugar Allergy Guide | Lifelab Testing

Sugar Allergy Guide

Last Updated: 6th March 2023 · Written by Kate Young

Sugar is found in fruits and vegetables and added to various foods to make them sweeter. You can also find it in milk, desserts, and condiments. When you have a sugar allergy, it can be tricky to avoid it, considering you’re likely to consume dairy, desserts, fruits, pastries, or even ice cream regularly. Sugar is also common in food products that you might not even know contain it – condiments like salad dressings, ketchup, sports drinks, and other bottled sauces. Glucose, a type of sugar, is essential to the body as it fuels the body’s cells and provides energy.

Sugar is a carbohydrate and is found in several forms, which include:

  • Maltose is formed when two glucose molecules are joined together, and it primarily occurs in grains like malt.
  • Fructose is a sugar naturally found in fruits, high-carbohydrate vegetables, and honey.
  • Sucrose, also known as “table sugar,” is a combination of glucose and fructose, and it comes from plants like sugarcane and beets.
  • Xylose comes from wood or straw and undergoes an enzymatic process to convert it to the sugar substitute we know as xylitol.
  • Glucose is a crucial energy source for the body and requires insulin.
  • Galactose is a sugar present in dairy products.
  • Lactose, a sugar found in dairy products, comprises glucose and galactose.

Can you be allergic to sugar?

If you feel lethargic or have a painful stomach after eating sugar, it could mean you’re allergic to sugar. Sometimes this feeling comes on after you’ve eaten a lot of sugar because your blood sugar spikes and then crashes and burns, leading to a “sugar hangover.” While having a sugar allergy is rare, it still happens {1}. A sugar allergy differs from a high sugar intake because it causes sugar allergy symptoms. It doesn’t take a certain amount of sugar for your immune system to react when you have a sugar allergy, you will experience symptoms after consuming a small amount.

If you have a sugar allergy, the first time you ingest the allergen your body forms an antibody called immunoglobulin E (IgE). So, the second time you eat the same allergen, your immune system sets off alarm bells and releases certain compounds, including histamines which end up causing sugar allergy symptoms. It doesn’t matter the amount of sugar you consume; the symptoms will be the same.

A more common reaction to sugar is sugar intolerance. A sugar intolerance occurs when your body doesn’t have enzymes to break down certain foods in your digestive system. It can also be due to particular sensitivities to specific foods’ chemicals, additives, or compounds. When suffering from sugar intolerance, you may be able to consume a certain amount of sugar and not get symptoms. The symptoms only occur when you consume more sugar than your body can break down, resulting in gastric symptoms because of fermentation in the large intestines. You can read more about the difference between an allergy and intolerance on our dedicated page.

Sugar allergy symptoms

Sugar allergy symptoms vary from one person to the next. Some people experience mild to moderate symptoms, which can be cured with over-the-counter medication. These symptoms of sugar allergy occur within two hours of consumption. They include:

A woman holding her stomach
A woman holding her stomach.
  • Redness of the skin.
  • Rashes or hives.
  • Nausea or vomiting.
  • Clogged sinuses.
  • Headaches.
  • Stuffy or a runny nose.
  • Stomach cramps.

In rare cases, some people experience severe symptoms of food allergies (anaphylaxis). When one experiences anaphylaxis, there is an urgent need for medical care because if you wait too long, you may go into anaphylactic shock or even die. These symptoms include:

  • Loss of consciousness.
  • A substantial decrease in blood pressure due to the onset of shock.
  • A fast heart rate.
  • A tightening or constriction of a person’s airway.
  • A swelling or closing of the throat makes breathing problematic.

Sugar allergy in children

If you notice that your baby isn’t feeling well every time you offer them something containing sugar, it could be because they have a sugar allergy. It can be hard to notice this in young children because they can’t speak for themselves, so it is up to you, as the caregiver, to gauge when they may have a food allergy. If you notice symptoms such as a runny nose, headache, stomach upset, or cramping in your child every time they consume sugar, it could be a sign that they have a sugar intolerance rather than being allergic to sugar.

However, suppose you notice your child suffering from symptoms like hives, vomiting, skin rash, or itchiness after consuming foods with sugar. In that case, they could suffer from mild sugar allergy symptoms. In severe cases, there may be symptoms like shortness of breath, wheezing, and loss of consciousness. These serious symptoms mean your baby needs to see a doctor with immediate effect. If you feel like your child could be suffering from any of these reactions every time you give them some sugary food or fruit, then you need to discuss this with your doctor so they can advise appropriately.

Difference between sugar allergy and intolerance

Sugar intolerance, unlike sugar allergy, doesn’t involve the immune system. Instead, an intolerance is caused by the body having difficulty digesting or processing sugar. Sugar intolerance is more common than sugar allergy and you’ll find that people suffer from different types of sugar intolerances. For example, people who can’t digest the sugar in milk (lactose) have lactose intolerance. While a sugar allergy involves the body’s IgE, sugar intolerance causes mishaps in the gastrointestinal tract. When the body lacks enzymes to digest certain sugars, it sends undigested sugar into the large intestines. Here it causes fermentation resulting in symptoms like bloating, diarrhoea, and gassiness, among other symptoms.

When it comes to sugar allergy, it doesn’t matter the amount of sugar one consumes, they will experience common sugar allergy symptoms if they have sugar allergies. However, regarding sugar intolerance, the amount of sugar one consumes matters. Everyone with sugar intolerance has a specific limit of sugar that they can consume without getting intolerance symptoms. However, if you need to know your amount, you can cut off sugar from your diet for about four weeks and then reintroduce it in small amounts while keeping a record through an elimination diet. You can do this after consulting your doctor so they can help you do it safely. If you have sugar intolerance, you’re most likely to be intolerant to fructose, lactose, or both, since these are the main culprits {2}.

Sugar allergy testing

basic allergy test
Basic Allergy Test.

If you notice that you suffer from symptoms every time you consume sugar, it may be because you have an allergy to sugar. However, considering sugar is often a hidden ingredient within many foods, it may be beneficial to rule out the common food allergens as causes first. To do this, you can order an Allergy Test which tests for the most common 38 food and inhalant allergies.You’ll then get a list of allergens you need to avoid. Having surety over how to handle your diet will help you figure out better ways to manage your allergies. When you think you may have specific allergies and intolerances, it leads to avoiding these foods. Therefore, being sure of these allergies will help you to handle them better. You’ll now be in control of your diet, preventing accidental allergen exposure that may result in allergy symptoms.

Allergy to sugar substitutes

Since you need to avoid sugar, you can still use these substitutes to sweeten your food and drinks without bringing up sugar allergy symptoms. These include:

  • Aspartame (Equal, NutraSweet).
  • Sucralose (Splenda).
  • Stevia.
  • Saccharin (Sweet’N Low).

You may have to avoid foods containing sugar, including sweeteners like honey, juice, molasses, and agave. If lactose intolerant, you must avoid any foods containing dairy or dairy byproducts. Alternatively, you can purchase over-the-counter lactase tablets to help digest dairy products’ sugar.

Final thoughts on sugar allergy

If you experience allergy symptoms but you’re unsure what’s causing them, we recommend you take an Allergy Test to help you determine the type of foods you need to cut off from your diet. Once you get your list, you can consult with a nutritionist on the best way to go forward and cut off the sugar or other food from your diet. Once you’ve adjusted your diet, you will be able to continue living life without experiencing uncomfortable symptoms.


  1. American Academy of Allergy, Asthma & Immunology. (
  2. Latulippe, M. E., & Skoog, S. M. (2011). Fructose malabsorption and intolerance: effects of fructose with and without simultaneous glucose ingestion. Critical reviews in food science and nutrition, 51(7), 583-592.

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