Preserving structure of plant-based foods limits fat absorption, study finds

A study by researchers from the Quadram Institute, King’s College London, the University of Surrey and the University of Messina postulates that preserving the natural structure of plant-based foods can limit how quickly fats are exposed to digestive enzymes in the stomach. This helps to regulate the amount of fat absorbed by the body, the study, which published in the Journal of Functional Foods, argued.

Dr Cathrina Edwards from the Quadram Institute explained: “If the natural plant structure is maintained the level of fat the body absorbs is greatly reduced, helping in weight management and potentially helping to reduce incidences of cardiovascular disease.”​

Building on previous research that found consumption of whole almonds - which contain 50% fat – doesn’t result in weight gain, the researchers designed a test to investigate the effects different processing methods had on how almonds are ingested by the body. 

Almond flour versus almond chunks

The researchers provided a study participant with two almond muffins: one made with 2mm almond chunks and one made with almond flour. The muffins were chewed as normal and then put into an instrument known as the Dynamic Gastric Model. This equipment accurately mimics the physical and chemical conditions of the human stomach and small bowel, enabling the researchers to calculate how much fat had been released.

After 60 minutes in the model stomach, which is the time calculated for this meal to pass through in humans, over 40% of the total fat content had been released from the muffins made with almond flour, but just under 6% had been released from the muffins made with larger almond chunks.

Samples taken from the simulated small bowel showed that after 9 hours of digestion, 97% of the fat from the muffin made with flour was released, and only 60% of fat in the muffin made with almond chunks was released.

These findings were supported by results from a human study with a volunteer who had an ileostomy operation, allowing a direct comparison with the model.

The researchers concluded that maintaining the structural integrity of the tough cell walls, which form dietary fibre, surrounding the fat-rich cells in almonds was the main factor in determining the digestibility of fats.

The study was funded by the Biotechnology and Biological Sciences Research Council. The Almond Board of California supplied the almonds.

Source: Journal of Functional Foods

Published online: doi: 10.1016/j.jff.2017.07.046​

“In vitro and in vivo modeling of lipid bioaccessibility and digestion from almond muffins: The importance of the cell-wall barrier mechanism”​

Authors: Terri Grassby, Giuseppina Mandalari, Myriam M.-L. Grundy, Cathrina H. Edwards, Carlo Bisignano, Domenico Trombetta, Antonella Smeriglio, Simona Chessa, Shuvra Ray, Jeremy Sanderson, Sarah E. Berry, Peter R. Ellis, Keith W. Waldron