Median cost, in pence sterling per 100 g*, of gluten-free foods and percentage difference in cost between gluten-free (GF) and gluten-containing (GC) foods in regular and premium supermarkets
| Food categories | Premium Supermarkets | Regular Supermarkets | Budget | Health food stores | Online stores | Median (IQR) % difference Premium | between GF and GC* Regular | P values |
| White bread loaf | 65 (61–68)†
‡
§ n=10 | 57 (52–60)†
¶
** n=10 | 105 n=1 | 151 (150–156)‡
¶
†† n=6 | 74 (65–144)§
**
†† n=10 | 273 (79–467) | 495 (457–565) | 0.077 |
| Brown bread loaf | 69 (66–72)†
‡ n=10 | 55 (46–67)†
¶
** n=7 | 56 n=1 | 107 (106–112)‡
¶
†† n=6 | 76 (65–86)**
†† n=10 | 255 (187–324) | 400 (400–800) | 0.014 |
| White Bread rolls | 92 (90–93)†
‡ n=10 | 67 (66–76)†
¶
** n=10 | - | 150 (150–152)‡
¶
†† n=6 | 94 (81–127)**
†† n=10 | 300 (210–389) | 393 (363–578) | 0.134 |
| Brown bread rolls | 103 (96–103)†
‡ n=7 | 86 (70–97)†
¶
** n=10 | 70 n=1 | 150 (153–152)‡
¶
†† n=6 | 102 (91–147)**
†† n=10 | 281 231–281) | 536 (450–650) | 0.001 |
| Flaked breakfast cereal | 92 (92–92) n=5 | 81 (66–85) n=10 | 65 n=1 | 69 (69–78) n=10 | 100 (66–119) n=10 | 109 (109–117) | 54 (51–181) | 0.812 |
| Cereal bars | 176 (172–257) n=10 | 164 (62–182)¶
** n=10 | 206 n=1 | 231 (231–236)¶ n=7 | 232 (184–294)** n=9 | 34 (30–78) | 26 (−49–40) | 0.289 |
| Pasta | 50 (40–59)‡
§ n=10 | 34 (26–65)¶
** n=10 | 32 n=1 | 126 (117–130)‡
¶ n=10 | 93 (72–111)§
†† n=10 | −12 (−21–15) | 58 (38–227) | 0.004 |
| Plain flour | 29 (18–40)† n=10 | 17(17-17)†
¶ n=10 | - | 43 (25–51)¶ n=5 | 19 (17–44) n=10 | 38 (−32–100) | 198 (55–398) | 0.160 |
| Crackers/crispbreads | 211 (160–259)†
‡ n=10 | 118 (101–191)†
** n=10 | 179 n=1 | 58 (58–170)‡
†† n=9 | 239 (146–294)**
†† n=10 | 110 (84–123) | 108 (50–313) | 0.002 |
| Sweet biscuits | 139 (139–141)†
‡ n=5 | 110 (75–130)†
¶
** n=10 | 93 n=1 | 172 (158–172)‡
¶ n=7 | 189 (126–234)** n=10 | 124 (124–128) | 84 (19–277) | 0.108 |
| Whole sponge cake | 110 (80-82)§ n=5 | 84 (66–91)** n=10 | - | 106 n=1 | 177 (100–220)§
** n=7 | 27 (25–33) | 38 (11–61) | 0.176 |
*Cost for each food was calculated as the mean cost cheapest and most expensive for each store. The Median values (inter-quartile range) are presented for each store type. Data is non-parametric, Kruskal-Wallis analysis undertaken to determine difference between store types; a significant difference between groups was observed for all food categories (P<0.05), except flaked breakfast cereals and oats. Mann Whitney tests to compared between store categories, Significant difference (P<0.05) between
↵†premium and regular supermarkets,
↵‡premium and health food stores,
↵§premium and online stores,
↵¶regular supermarkets and health food stores,
↵**regular supermarkets and online stores,
↵††health food stores and online stores. Convenience stores did not stock any of the GF foods surveyed. Sandwiches and wraps only one option available from two regular supermarkets.