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Alharazi, Waad (2025) The impact of yam (Dioscorea Spp.) on glycaemia. PhD thesis, University of Nottingham.

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Abstract

T2DM is the most common form of glucose homeostasis disruption. Dietary modifications are considered as a cornerstone in managing T2DM, and specific foods, known as functional food, have been used to manage it. Dioscorea spp., a plant consumed as a staple food in African and Asia, has shown health potential in treating glucose homeostasis disruption in laboratory settings and animal models. However, the impact of normal consumption with different preparations remains ambiguous. The aim of this thesis was to identify which of the commonly consumed D. spp., (D. alata (purple), D. rotundata (white) and D. cayenensis (yellow)) could be beneficial for controlling glycaemia. A systematic review was conducted to explore the literature in regards of yam impact on obesity-induced hyperglycaemia in animals and human, followed by an investigation into the macronutrient, mineral and antioxidant activity of the three yam species, prepared in three different ways (raw, boiled, baked). Furthermore, this thesis assessed yam water extracts in-vitro cytotoxicity, scavenging activity against H2O2 and as insulin analogue on C2C12 and L6 muscle cells. Then, it assessed glycaemic response in a clinical study comparing commonly consumed tubers, white and sweet potatoes. Results showed that D. alata demonstrated better nutritional values for controlling glycaemia with low carbohydrates, energy content and high protein, minerals and antioxidant activity. Moreover, D. alata had low toxic effect on muscle cells, and it increases glucose uptake. Furthermore, boiled purple yam showed prolonged glycaemic response suggesting multiple mechanisms and bioactive contents. However, more research is needed to establish precise intake recommendations. One of the main implications is the use of purple yam as an alternative in diabetic dietary guidelines and fully understand the relationship between consumption and health outcomes.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Jethwa, Preeti Rose, Peter
Keywords:	Functional foods; Glycaemic control; Glycaemic response; Yam consumption
Subjects:	Q Science > QP Physiology
Faculties/Schools:	UK Campuses > Faculty of Science > School of Biosciences
Item ID:	82013
Depositing User:	Alharazi, Waad
Date Deposited:	12 Dec 2025 04:40
Last Modified:	12 Dec 2025 04:40
URI:	https://eprints.nottingham.ac.uk/id/eprint/82013

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