Partially Hydrolyzed Guar Gum and Gut Health

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You are likely familiar with the importance of dietary fibre for health, but did you know there are different types of fibres which offer specific health benefits including soluble and insoluble fibre and some fibres are also considered prebiotics?  Read on to learn more about the types of fibre including the prebiotic fibre partially hydrolyzed guar gum (PHGG) and its benefits for gut health.

Dietary fibre is a key nutrient for overall health.  It is found in plant foods and is a non-digestible carbohydrate that your body cannot digest or absorb.  There are two main types of dietary fibres which include soluble fibre and insoluble fibre.

Soluble fibre

This type of fibre dissolves in water to form a gel-like material and helps to lower cholesterol and control blood glucose (sugar) levels.  It also helps to manage diarrhea and loose stools, or soften firm stools.  As well, it helps to have a healthier colon by supporting the growth of good healthy bacteria.  

Soluble fibre is found in oats, barley, psyllium, legumes such as beans and lentils, some fruits such as apples, pears, strawberries and citrus fruits and vegetables like broccoli, sweet potato, carrots and eggplant.

Insoluble fibre 

This type of fibre does not dissolve in water. It adds bulk to stools, therefore this type of fibre helps to keep you regular.

Insoluble fibre is found in wheat bran, whole grains, vegetables and fruits (especially with skins) and legumes such as beans and lentils.

Both types of fibre are important for good health and foods that contain fibre often have a mix of both types.  It is important to eat a variety of foods rich in fibre to get the health benefits of both types.

Did you know?

Fibres that feed beneficial bacteria in your gut are called prebiotics. 

Prebiotics are defined as: “A substrate that is selectively utilized by host microorganisms conferring a health benefit” (1). 

So, prebiotics act as a food source for the bacteria in your gut.  Your bacteria ferment “eat” the prebiotic fibre, thereby supporting the growth of good healthy bacteria.  The good bacteria also produce short-chain fatty acids (SCFAs) that act as a fuel source in our body and supports health.

Keep in mind, not all fibres are prebiotics.  In order to be considered a prebiotic, the fibre must pass through the gastrointestinal tract undigested and stimulate the growth and/or activity of certain good bacteria in the large intestine (2).

Types of prebiotic fibres

Some examples of prebiotic fibres include: 

  • Fructo-oligosaccharides (FOS), inulin or fructans
  • Galacto-oligosaccharides (GOS)
  • Partially hydrolyzed guar gum (PHGG)

Guar gum vs. partially hydrolyzed guar gum (PHGG)

What is guar gum?

Guar gum is derived from the guar bean which is a member of the legume family.  Guar gum consists of long chains of galactose and mannose sugar molecules which together form galactomannan.  It’s high in soluble fibre, so it’s able to absorb water and form a gel.  Guar gum has a high viscosity, which means when it’s mixed with solution it forms a thick, sticky gel.

Due to this gel-forming property, guar gum is frequently used as a food additive in many processed foods to thicken and bind products.  It may be used in foods such as:

  • Ice cream, sauces, spreads, yogurts and dressings

What is partially hydrolyzed guar gum (PHGG)?

An enzymatic hydrolysis process is used to cut up the long chains of galactose and mannose sugar molecules that make up guar gum into shorter chain lengths.  The end product is called partially hydrolyzed guar gum (PHGG), which has a greatly reduced viscosity, so it does not gel when mixed with solution and remains liquid.  PHGG is considered a soluble prebiotic fibre.

Where do I find PHGG?

As PHGG is enzymatically hydrolyzed from guar gum, it is not naturally found in food.  Instead, it is found in supplement form.  It is a powder that can be easily mixed with water and research shows it tends to be well tolerated.    

What are some gut health benefits of PHGG?

PHGG has a good amount of clinical research supporting its gut health benefits.  Positive impacts have been found for constipation, diarrhea and irritable bowel syndrome (IBS).

PHGG & constipation

Clinical studies examining patients with constipation have found PHGG improves stool consistency and bowel movement frequency, while also reducing symptoms such as abdominal pain and incomplete evacuation (3,4).

Research also suggests that PHGG consumption had a favourable impact on constipation prevention of a similar magnitude that was achieved with laxatives (5).

Furthermore, research has found PHGG reduces colonic transit time, therefore increasing the speed through which a substance moves through your colon (4).

The exact mechanism is not yet known, but speculate it may be due to SCFAs produced from the good bacteria in your gut fermenting “eating” the PHGG prebiotic fibre.  SCFAs support the cells in your gut and act as a fuel source.

PHGG & diarrhea

PHGG has also been studied in patients with diarrhea while receiving enteral nutrition (tube feeding) and found the water content of the stool decreased significantly and the frequency of daily bowel movements also decreased significantly.  The total level of SCFAs also significantly increased 4 weeks after the administration of the fibre (6).

Further, PHGG has shown to increase colonic transit time, therefore decreasing the speed through which a substance moves through your colon and thereby allowing more time for the bacteria in your gut to ferment the fibre and produce beneficial SCFAs (7).


Those with IBS experience symptoms such as cramping, abdominal pain, bloating, gas, and diarrhea or constipation, or alternating both diarrhea and constipation.

Clinical studies investigating PHGG in patients with IBS have found PHGG effective in reducing symptoms and improving quality of life (8, 9, 10).

What’s interesting about PHGG is its ability to help with both diarrhea and constipation. While researchers are still investigating exactly how it can both increase and decrease colonic transit time; it seems the key with PHGG is it’s able to normalize transit time, so it can speed it up or slow it down depending on the condition of the patient.

As always, if you’re thinking about a supplement, remember it’s important to speak with your healthcare professional before taking any supplement to make sure that you’re taking a supplement that’s right for you.

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