There is increased scientific interest in the effects of nutrition on cognition and well-being. Plant sourced polysaccharides play multiple roles in the biological processes required for health and well-being. This study explored the subjective experiential reports of well-being following intake of a plant derived polysaccharide supplement. The study used a 12 week double-blind, placebo controlled polysaccharide supplementation design. 109 middle-aged adults (45-60 years) took a standardised teaspoon of a combination of plant polysaccharides or a placebo twice daily for 12 weeks (3.6 g per day), and completed three, open-ended interviews at weeks 4, 8 and 12. Participants who took the polysaccharide supplement reported significantly more perceived beneficial changes in both physical and psychological well-being, specifically at week 12, compared to those who received the placebo. This study provides a starting point for understanding the perceived beneficial impact of polysaccharide interventions on aspects of well-being. Importantly, as a health-related application of polysaccharide science, this research supports the relationship that is emerging between the properties and function of polysaccharides. It is essential that future research assesses the effects of polysaccharide intake on a range of physical and psychological well-being outcomes to further the understanding of structure-function relationships with the aim of enhancing the functional health and well-being of individuals.