An investigation into the availability, cost and nutritional implications of a low FODMAP diet.
Background: Evidence has shown that dietary restriction of Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPs) is effective in the management of symptoms associated with irritable bowel syndrome (IBS). While the diet has proved effective in symptom alleviation, it can be burdensome for patients to follow and result in inadequate nutrient intake. Few studies have examined the availability, cost and nutritional implications of the low FODMAP diet; factors which collectively act as potential barriers to dietary adherence. These barriers are particularly relevant for patients with poor access to supermarkets and patients of low-income groups. Therefore, further research is needed to bridge the evidential gap in low FODMAP research in order for practitioners to provide practical, person-centred advice. Objective: The aim of the study was to explore the availability, cost and nutritional implications of following a low FODMAP diet by surveying a range of supermarkets across areas of varying deprivation in Edinburgh. Design: This study was an observational, cross-sectional, survey design. Two areas of high and low levels of deprivation were identified based on the Scottish Index of Deprivation (SIMD) and a total of six stores of different categories (Regular, Budget, Convenience) were surveyed across both areas. A typical Scottish shopping list and 24-hour meal plan were drafted based on Scottish National Diet and Nutrition Survey (SNDNS) and Scottish Health Survey (SHS) data and low FODMAP equivalents were created. Each store was systematically explored and total availability and the cost per unit and the price per 100g of items on the typical Scottish shopping list and low FODMAP shopping list were examined and compared. Nutritional analysis software was used to assess the nutritional composition of both 24-hour meal plans and these were compared with the Estimated Average Requirements (EARs) and the Reference Nutrient Intakes (RNIs) for a 22-year-old female, who was used as model for nutritional comparison. Results: In general, there was limited availability of low FODMAP foods across both areas of deprivation, with only 25% of stores across both areas stocking every item on the low FODMAP shopping list. Regular supermarkets across both areas had the best availability of low FODMAP products (100%), whereas convenience (84.7%) and budget (80.4%) supermarkets had poorer total availability for low FODMAP food items. Socio-economically, the area of high deprivation had better overall availability (93%) in comparison to low FODMAP availability in the area of low deprivation (84%). On average, the low FODMAP diet was more expensive than the typical Scottish diet for price per item and price per 100g in both the area of high deprivation (£19.82 vs £27.33, £8.16 vs £12) and also in the area of low deprivation (£18 vs £22.61, £8.13 vs £11.49). The low FODMAP diet met the nutritional guidelines for a 22-year-old female however, reductions in total carbohydrate intake (283g/d vs 258g/d) and calcium intake (1350mg/d vs 1000mg/d) were seen in comparison to the typical Scottish diet. Conclusion: The study demonstrated that there is less availability of low FODMAP foods across both areas of deprivation and they are generally more expensive than foods on a typical Scottish diet. This may impact on dietary adherence, particularly for those experiencing significant economic constraint or those living in areas with poor access to regular supermarkets. Furthermore, the current study showed that the low FODMAP diet is nutritionally adequate for a 22-year-old female but had reduced intakes of carbohydrate and calcium.