Is corn syrup low FODMAP? (includes common brands)

Trying to work out whether corn syrup is low FODMAP when taming your sweet tooth can be a ‘sticky’ event.

Regular corn syrup is often confused with high fructose corn syrup, an undesirable mistake to your low FODMAP diet.

In this article we delve into the FODMAP status of corn and other syrups, addressing common misconceptions, how they are used and where to find them.

What is corn syrup?

Corn syrup is a sweet thick syrup made from breaking down corn to produce the naturally occuring sugars from inside. 

To begin the process, manufacturers need to make cornstarch from the corn. This is done by taking the endosperm of the corn kernel and grounding it down to form a fine powder.

The corn starch is then mixed with water and amylase enzymes. These enzymes are key to the breakdown of starch into sugars.

Amylase will first break down the starch into oligosaccharides and then, with the addition of enzyme glucoamylase, into glucose sugar, forming corn syrup (1).

Is corn syrup low FODMAP?

Although there is currently no research that looks specifically into the effects of consuming corn syrup on IBS, we know that corn syrup is low FODMAP.

FODMAPs are a group of carbohydrates which can trigger IBS symptoms. Foods without these in them are less likely to cause issues for your IBS and make up the low FODMAP diet.

Regular corn syrup is low FODMAP as it is made up of 100% glucose, and glucose has not been found to produce symptoms of IBS when consumed (2).

This is good news if you find yourself using corn syrup as your go to sweetener of choice.

However, despite not producing any IBS symptoms, we still recommend that it is eaten in moderation as corn syrup is sugar.

Corn syrup can play a part of a healthy diet, but in excess can contribute to unwanted health problems such as diabetes and tooth decay (3).

How is corn syrup used?

Corn syrup has a variety of uses due to its acidity and fudgy texture.

The fudgy texture is extremely useful for bakers as it can create a chewy cookie rather than a crisp one.

The acidity characteristic plays a key role in forming carbon dioxide when mixed with baking soda to contribute to the rise in baked goods (4).

Examples of corn syrup uses include:

• Baked goods such as pecan pie
• Jams and Jellies
• Candy making
•  Caramel and fudge
• Marshmallows

Corn syrup can also be bought on its own if you fancy some home cooking. Some common US brands include;

•  Karo
• Golden Barrel

What is high fructose corn syrup?

High fructose corn syrup (HFCS) is different to regular corn syrup. The enzyme glucose isomerase is added to regular corn syrup to turn some of the glucose into fructose sugars (5).

There are different types of HFCS, but the most commonly used ratio is 55% fructose and 45% glucose (6). 

The fructose content means that HFCS is much sweeter than regular corn syrup, therefore it is commonly used in food manufacturing where less is needed to get the same level of sweetness.

Is high fructose corn syrup high FODMAP?

High fructose corn syrup is high FODMAP and should be avoided by anyone on the low  FODMAP diet or who has a fructose intolerance.

As the percentage of fructose becomes more than the glucose content, it becomes harder to absorb in the intestine. 

This is because the human intestine lacks enzymes to digest and transport fructose and would therefore look to ‘piggy back’ on a glucose molecule to be absorbed via a glucose transporter (GLUT- 2).

However, as there is more fructose to glucose, the remaining fructose is unabsorbed. This may lead to water being drawn into the bowels and the production of gas resulting in IBS symptoms (7). 

As HFCS is so readily used in food manufacturing, it is important to read food labels carefully and avoid processed foods containing HFCS on a low FODMAP diet (8).

HFCS is commonly found in these items:

• Fast food e.g. A McDonalds Big Mac
• Breakfast cereals e.g. Frosted Flakes 
• Baked goods e.g. Twinkies 
• Soft drinks e.g. Coca Cola

What is light corn syrup?

Light corn syrup is corn syrup that has been flavored with salt and vanilla and much like regular corn syrup, light corn syrup is low FODMAP.

The vanilla flavor means that it is used predominantly in home baking, for example cakes and cookies.

The brand Karo is the main manufacturer of light corn syrup in the United States.

What is glucose-fructose syrup and isoglucose?

Glucose-fructose syrup (GFS) is a liquid sweetener of varying compositions, with a fructose content ranging from 5-50% (9). 

In Europe, isoglucose is type of GFS and refers to a syrup with more than 10% fructose (10).

GFS is made in a similar way to corn syrup, by extraction of sugars from a source of carbohydrate. Historically maize was preferred but using wheat is now common practice (10).

Is glucose-fructose syrup low FODMAP?

As the ratio of glucose remains higher or equal to fructose, it means that glucose-fructose syrup is low FODMAP. 

There are enough glucose molecules to ensure that all of the fructose molecules can latch on and be absorbed properly via the GLUT-2 transporter in the intestine. 

However, even though isoglucose is a type of GFS, we don’t know the exact fructose content. Therefore we recommend that you avoid products that have isoglucose (11).

If you live in Canada, HFCS is called glucose-fructose syrup and must be avoided during the first phase of your low FODMAP diet (11).

How is glucose-fructose syrup used?

GFS is used predominantly in manufacturing due to specific characteristics such as preventing crystallization in confectionery and to prevent candy from sticking to wrappers.

The use of GFS is more common in the UK and Europe than in the US, and can be found in the following examples: 

• Cereal bars e.g. Kellog’s Coco Pops Breakfast Cereal Bar 
• Jelly e.g. Hartley’s Lime Jelly 
• Sweets/Candy

Is high fructose corn syrup low FODMAP?

Fructose-glucose syrup refers to corn syrup that contains more than 50% fructose (9). Therefore, HFCS is a type of fructose-glucose syrup.

As the fructose content exceeds the glucose content, fructose-glucose syrup is high FODMAP and should be avoided.

Table explaining the FODMAP content of different types of corn syrup FODMAP content

Type	Low FODMAP?
Corn Syrup	✓
High Fructose Corn Syrup	X
Light Corn Syrup	✓
Glucose-Fructose Syrup	✓
Fructose-Glucose Syrup	X

Summary

Regular corn syrup is low FODMAP and therefore does not cause IBS symptoms.

However, there are certain manufacturing processes used to make it sweeter which add in additional fructose.

Depending on how much fructose is added will determine whether the syrup remains low FODMAP or not.

There are other ways you may like to sweeten your food. We have covered blog posts on is maple syrup low FODMAP and what is the link for sugar & IBS.

Article written by Stella Gordon, Student Dietitian, reviewed by Kirsten Jackson, Consultant Dietitian BSc Hons, RD, PG Cert