Section of Metabolic Medicine, Food and Macronutrients

The overall aims of this project are to investigate the effects of processing on the formation and glycaemic impact of RS5 using the potato as a model of a starchy food. The potato represents an ideal food to study, as it remains in its native state from field to fork, thus minimising factors that could potentially confound the interpretation and translation of our results.

A new form of resistant starch has recently been identified in food which is created by the interaction between starch and fat molecules when the food is cooled and reheated. This new form of starch has been designated as 'type 5 resistant starch' (RS5).  The presence of a small amount of fat (~5% recommended daily intake) within the food matrix is now known to be critical for the formation of this resistant starch and highlights the importance of looking at whole "food" rather than simply the individual "nutrients". While published data on RS5 has so far been restricted to laboratory and animal models, our own human pilot data has revealed that the beneficial effects can be acquired through simple home processing (chilling and reheating) of starchy food (pasta/potatoes), which can reduce the glycaemic impact by at least 25% in a single serving.

The potential translation for this research is far reaching, with starch contributing up to 45% of daily energy intake, simple changes to processing could have large-scale effects on public health.

Raised blood cholesterol (also referred to as blood LDL-cholesterol) is a major risk factor for developing heart disease. Dietary saturated fat is recognised as the main dietary component responsible for raising blood LDL-cholesterol, and reducing its intake has been the mainstay of dietary guidelines for the prevention of heart disease for over 30 years. However, there is very little evidence for a direct link between the intake of saturated fat and risk of dying from heart disease. One explanation for this, is that the link between saturated fat intake and heart disease is not a direct one, but relies heavily on the ability of saturated fat to raise blood LDL-cholesterol levels. This LDL cholesterol-raising effect of saturated fat is complex, and highly variable between individuals because of differences in the metabolism of dietary fat and cholesterol between people which this study will be investigating. The results will also make it possible to tailor dietary advice to subgroups of individuals who more sensitive to the effects of saturated fat on LDL-C, and who stand to gain the greatest health benefit of dietary intervention, in terms of a reduction in CVD risk. 

Interested in helping with this study? Please check out our social media page!

Contact Dr Barbara Fielding or Dr Nicola Jackson if you would like to collaborate with us on measurements of stable isotopes in metabolites, including glucose, fatty acids and glycerol.

Two intermittent fasting variants, intermittent energy restriction (IER) and time-restricted feeding (TRF), have received considerable interest as strategies for weight-management and/or improving metabolic health. With these strategies, the pattern of energy restriction and/or timing of food intake are altered so that individuals undergo frequently repeated periods of fasting. The group are currently involved in a number of projects which aim to gain a greater understanding of the metabolic effects of intermittent fasting, beyond its effects on weight-loss. Contact Dr Denise Robertson or Dr Rona Antoni if you would like further information.