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Discovering a new whey to reduce fat

TResearch Autumn Winter 2021

Teagasc researchers have found a way to reduce weight gain from foods rich in fat, potentially minimising the harmful effects of dietary fat. Here, we map the development of their research and their findings over the years.


Teagasc researchers decided to look for food ingredients that, when included in fatty foods, can reduce capacity to cause weight gain and the development of obesity and associated diseases like diabetes.

Teagasc’s Kanishka Nilaweera says: “Bovine (cattle) milk is a rich source of nutrients providing many health benefits, so we looked closely at key components in milk that can be used as food ingredients. We focused our attention on whey – a high-quality protein found in cows’ milk.”


Initial research conducted on mice showed that whey protein isolate (WPI) – the protein-rich form of whey – reduced body fat mass and weight gain when consumed as part of a high-fat diet.


“This was an exciting year as we provided the first insight into the potential mechanism for the previously mentioned WPI effects by showing that the proteins caused shrinkage of the gut,” says Kanishka.


To further explore the bioactivity in WPI, work was undertaken using two proteins present in WPI, namely bovine serum albumin (BSA) and lactoferrin (Lf). “We found that BSA reduced body fat and weight gain from a high-fat diet, while the Lf had no direct impact on weight gain,” explains Kanishka.

“However, Lf did affect a stress-related parameter that is also linked to weight management. These data suggested that individual whey proteins act on different components affecting weight gain in the host, possibly via the gut as the key route of action.”


Re-visiting the impact on the gut, the researchers presented their next set of data showing that WPI also affected gut associated microbes (tiny living organisms in the human body). 


“Having established a tentative link for the mode of anti-obesity action of WPI, we temporarily set our sights elsewhere to highlight a host mechanism that tries to counteract interventions, such as dieting, that reduce body fat and weight gain,” says Kanishka.

“The host mechanism, which involves an increase in gut size with the loss of body fat, was found to have evolved to allow more food to be ingested and accommodated in the enlarged gut, so that it can then be used to replenish the lost body fat.

“The fact that WPI reduced gut size provided the incentive to push our work forward.”


Expanding their previous work, the researchers assessed the impact of varied quantities of dietary fat and proteins as well as protein quality (casein which is slow-digesting and WPI which is fast), on the sizes of over 20 different body tissues that together determine body weight.

“By looking at over 20,000 data points, we concluded that the intake of high quantities of dietary fat with casein cause an unhealthy expansion of many tissues – including the gut – which together increase weight gain and inflammation,” explains Kanishka.

“By swapping casein with WPI, we reduced tissue expansion – including gut size – as well as weight gain and inflammation.”

The effects were accompanied by altered gut microbes in WPI-fed animals. The researchers further found that microbes are the activity of WPI that reduce weight gain. Further analysis revealed that the dietary fat consumed by the animals had been modified by WPI-sensitive microbes. This work has significant appeal because if people find it hard to change their preference for high energy fat-rich foods, the solution may be to find a way to change them inside the body with the help of gut microbes, so that the harmful effects of dietary fat can be minimised.

The researchers published their findings in May 2021.


We are very grateful to Teagasc for the initial funding that provided the solid platform to build our story, which we extended with the help of many past and present researchers and, more recently, using funds from the SFI-BBSRC partnership and the VistaMilk SFI Research Centre. The authors would also like to acknowledge John Speakman of the University of Aberdeen for his contribution to these studies.

Further reading

Nychyk, O. and Barton, W. et al. (2021) Protein quality and quantity influence the effect of dietary fat on weight gain and tissue partitioning via host-microbiota changes. Available at: https://www.sciencedirect.com/science/article/pii/S2211124721004277?via%3Dihub


Oleksandr Nychyk, Research Scientist, Teagasc Food Research Centre, Moorepark, Fermoy,

Co. Cork

Wiley Barton, Research Scientist, Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork

VistaMilk SFI Research Centre, Fermoy, Co. Cork

Paul D. Cotter, Research Scientist, Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork

VistaMilk SFI Research Centre, Fermoy, Co. Cork

Kanishka N. Nilaweera, Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork

VistaMilk Research Centre, Fermoy, Co. Cork kanishka.nilaweera@teagasc.ie