How processing affects fat absorption from plant-based foods

Preserving the natural structure of plant-based foods can help regulate the amount of fat absorbed by the body, according to a new study.

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

Focusing on almonds supplied by the Almond Board of California, which contained 50% fat, researchers investigated the effects different processing methods had on how almonds are ingested by the body.

Despite being a high fat food, it has been shown previously that eating whole almonds doesn’t result in weight gain. Investigating why this might be, the researchers provided a study participant with two almond muffins, one made with almond chunks (2mm) and one made with almond flour, which has much smaller particles (at less than 0.5mm).

The muffins were chewed as normal but instead of swallowing were put into an instrument known as the Dynamic Gastric Model, which 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 nine hours of digestion, almost all (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.

Dr Cathrina Edwards from the Quadram Institute, says, “What we have found is that 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.”

Dr Karen Lapsley, chief scientific officer at Almond Board of California, adds, “As plant-based foods become more popular, food manufacturers are increasingly finding new and innovative ways of incorporating plant-based ingredients such as almonds into formulations.

“It’s encouraging to see another piece of research reinforcing the health benefits of almonds and the role they can play in creating a healthier snack offering for a growing health conscious population.”

The study was funded by the Biotechnology and Biological Sciences Research Council.

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