Pectin, another reason to love mangoes

24 May 2021

The dietary fibre pectin found in fruit and vegetables plays a crucial role in digesting fats and improving gut and heart health. 

Mangoes, apples and citrus fruit are all good sources of the dietary fibre pectin, and new research reveals how it helps to regulate cholesterol levels. 

Dr Nima Gunness

The findings come from Dr Nima Gunness at the Queensland Alliance for Agriculture and Food Innovation (QAAFI), a research institute at The University of Queensland. 

Her work involves translating food, nutritional science and health science into effective information that can reliably promote wellbeing.  

“Identifying the role of dietary fibre is the focus of my most recent research,” Dr Gunness said. 

Dietary fibres are composed of soluble and insoluble fibres, which are located in the cell walls of plants and are not digested by the human body. 

“Typically, the insoluble fibres are viewed as a way to maintain bowel regularity and provide bulk to diets without associated calories,” Dr Gunness said. 

Mango and apple on a black stone plate

Some soluble fibres, such as pectin, ferment in the lower gut of the human body.  

They are known to have beneficial effects on fat metabolism and improve cardiovascular health, such as blood levels of cholesterol and triglycerides – although how they do this was a mystery for a long time. 

Now, Dr Gunness has discovered a link between soluble fibre and fat metabolism through previously unsuspected impacts on bile acid metabolism.  

The good bile 

New research uncovers a link between soluble fibre and fat metabolism, through previously unsuspected impacts on bile acids.

Soluble fibre in the form of pectin (sourced from fruits and vegetables) promotes the production of ‘therapeutic’ bile acids.  

This subtype of bile acids helps maintain a healthy digestive tract and cholesterol balance. This subsequently protects the cardiovascular system.  

The soluble fibre also reduces levels of ‘toxic’ bile acids known to promote diseases, including colorectal cancer. 

The therapeutic form of bile acid is called ursodeoxycholic acid (UDCA), while the toxic form is called lithocholic acid (LCA). 

“The link between dietary fibre, the digestion of fats and bile acid chemistry is an emerging area of importance when it comes to food choices,” Dr Gunness says.  

“I think people will soon be hearing a lot more about ‘therapeutic bile acids’ and the importance of dietary fibre in producing them.” 

QAAFI’s Centre for Nutrition and Food Sciences uses advanced research methods to probe the rich and deeply interconnected complexity between food, healthy physiology and metabolism.  

Her research examined a class of soluble fibre called pectin.  

Unlike the beta-glucans that are found in, for example, grains such as oats and barley, pectin is sourced from fruits and vegetables.  

Identifying health benefits 

Dr Gunness’s study into the physiological effects of pectin involved a trial with pigs because of their physiological similarity to humans.  

The analysis included impacts on the digestive tract and on the level of markers for cardiovascular health in plasma.  

The pigs were fed three contrasting diets: a standard ‘control’ diet; one containing unprocessed pectin sourced from mango pulp; and one containing extracted pectin.  

The pigs were gradually introduced to their diets before the 28-day feeding experiment officially began. 

Comparing the impacts of the three diets at the end of four weeks, the study confirmed that pectin reduces cholesterol levels in plasma. Levels fell 18 per cent in animals fed the extracted pectin diet and 10 per cent for unprocessed pectin diet.  

Both pectin diets also increased levels of therapeutic bile acids and markers of gut health, implying the enhancement of good gut microbiota. 

Dr Gunness says the study also shed light on the mechanisms mediating these important effects. 

Citrus pulp.

She said bile acids enter the small intestine to assist the digestion of fats.  

The primary bile acids are formed in the liver from cholesterol and stored in the gall bladder before they are excreted into the duodenum (first part of the small intestine) when food is released from the stomach. 

“The primary bile acids released by the gall bladder undergo a series of chemical transformations as they travel through the digestive tract,” Dr Gunness said.  

“These chemical transformations can result in both healthy and toxic forms of bile acid depending on the state of the digestive tract, particularly the gut microbiota.” 

“What we saw is that pectin exerts beneficial effects by priming the digestive system towards transforming bile acids into forms that benefit gut and cardiovascular health. 

“The key health benefits of pectin can be obtained with both fruit pulp and extracted pectin,” Dr Gunness said.  

“That creates an opportunity to consume more fruits and vegetables, and to beneficially supplement diets with extracted pectin – although the extracted pectin should have particular characteristics,” she said. 

“The extraction processes involved are critical for health benefits, which means that not all supplements will give the same benefits.”  

The study was funded by the Australian Research Council (ARC) and undertaken in collaboration with the University of Adelaide and the University of Melbourne via the ARC Centre of Excellence in Plant Cell Walls.  

Contact: Dr Nima Gunness: E M: 0413050292 & Margaret Puls, QAAFI Communications: E:,  M: +61 419 578 356 

The Queensland Alliance for Agriculture and Food Innovation is a research institute at The University of Queensland supported by the Queensland Government via the Queensland Department of Agriculture and Fisheries.