The availability and cost of a milk-free diet for cow's milk protein allergy

Abstract

Background: Cow's milk protein allergy (CMPA) is the most common food allergy, and adherence to a milk-free diet is essential, particularly in immunoglobulin E-mediated CMPA sufferers (Benhamou et al., 2009). No studies have looked into the practical aspects of a milk-free diet. The aim of this project was to evaluate how the availability and cost of a milk-free diet compares with that of one containing cow's milk protein. Methods: A cross-sectional survey was conducted in the London Borough of Harrow and three major superstores in an urban setting (inclusion criteria of ≥25 000 sq ft) were randomly selected. Two shopping baskets were created; basket A with commonly consumed foods (bread, biscuits, milk, packaged fruit/vegetable salads, and ready meals which contained ≥12% protein from nondairy protein sources) based on the Eatwell plate (Food Standards Agency, 2007), and basket B with their cow's milk-free alternatives. The price and number of varieties were recorded and analysed for each food group per basket. Pearson's chi-squared and Wilcoxon-rank sum tests were conducted for availability and cost of each food type in both baskets. Results: The availability of foods suitable for a CMPA diet (basket B) was lower than basket A: 74% bread, 15% biscuits, 26% milk and 25% ready meals compared to 26%, 85%, 74% and 75%, P-values of 0.001, 0.002, 0.001 and 0.005, respectively. The availability of fruit/vegetable salads was not statistically significant between the two baskets. Regarding cost, bread in basket A was found to be significantly more expensive than in basket B, whereas milk substitutes (all superstores) and ready meals (superstore 2 only) were significantly more expensive in basket B (Table 1). The cost of biscuits and fruit/vegetable salads between the two baskets was not significantly different. Table 1. Median cost of foods in standard basket A and CMPA basket B (pence/100 g) Basket Superstore 1 Superstore 2 Superstore 3 A B P A B P A B P Bread 17.3 12.5 0.001 16.4 15.3 0.001 17.1 14.9 0.008 Biscuits 25.1 24.8 0.651 24.5 12.2 0.161 27.1 21.3 0.390 Milk or substitutes 8.5 12.5 0.002 7.8 9.4 0.001 7.9 12.4 0.003 Ready meals 63.4 70.1 0.592 54.1 66.2 0.004 61.1 66.0 0.390 Fruit/vegetable salads 50.0 65.3 0.781 33.3 49.2 0.223 65.1 62.5 0.803 Discussion: A similar previous study has investigated the practical aspects of a gluten-free diet and found that this is typically more restrictive than its alternatives (Lee et al., 2007). The findings from the present study provide further evidence that specialist diets are generally more expensive and less available than an unrestricted diet. This could present a barrier to people trying to follow a special diet and might be addressed by increasing awareness of the need for milk-free products by manufacturers and retailers. Dietitians have a role to play in this and in producing CMPA resources and providing education that takes account of barriers like cost and availability. Conclusions: It can be concluded from this study that, overall, a milk-free diet is less accessible and more expensive than an unrestricted milk-containing diet.