Studies of the nutritional quality of commercial ‘ready to eat‘ infant foods in the United Kingdom

Infancy is a time of rapid physiological (e.g. anthropometric, immunological and neurological) development. Hence, during this period of life nutritional requirements are at their highest in relation to body mass. There is a paucity of data with respect to the nutritional quality of complementary foods manufactured in the UK for infants and young children. The primary objective of this study was to examine the nutritional value of ‘ready to feed‘ complementary infant foods on the UK market in order to ascertain their suitability, relative to dietary guidelines, for the target group. Quantitative analysis was conducted on eight different products representing four popular commercial brands (meat and vegetable based) currently on sale in the UK for infants aged between 6-12 months. The chemical analyses conducted included Kjeldhal for protein, acid hydrolysis and extraction for fat, phenol sulphuric acid for carbohydrate and AOAC 985.29 for fibre. The results of these studies were referenced to the Recommended Nutrient Intake (RNI) values for 6 to 9 months old children, and a listing of the entire daily intake of nutrients was composed taking into consideration the nutrient and energy intake from milk consumption in order to (1) accurately estimate the daily intake of these nutrients derived from commercial infant food consumption, and (2) ascertain their nutritional suitability relative to dietary guidelines for the 6-9 month age group. The only significant difference found between different product varieties (meat and vegetable-based) was with respect to the protein content (p = 0.04) per 100 g of food. The experimentally determined concentrations of macronutrients (g/100 kcal) were compared to the declared values provided by the manufacturers on the product labels and, despite some variations, the values obtained comply with regulatory requirements (Commission Directive 2006/125/EC). The total daily intake of fat (27.0 g/day), based on the menu composed from commercial complementary food, is suggested to exceed the Dietary Reference Values (DRVs) for fat (31%), if the intake of snacks and desserts are incorporated. The aforementioned results imply that the formulations of the recipes, based on a standard commercial menu, are of significant importance in relation to the nutritional quality of the diet of infants. In terms of elemental analysis, the concentrations of up to twenty (essential and non-essential) elements in a selected range of sixteen different products representing meat, poultry, fish and vegetable base varieties were established by ICP-OES and ICP-MS. Six major essential elements, namely: calcium, iron, magnesium, potassium, sodium and zinc were measured by ICP-OES. The concentrations of six essential trace elements (selenium, molybdenum, cobalt, copper, chromium, manganese) and eight non-essential, potentially toxic, elements (arsenic, barium, nickel, cadmium, antimony, lead, mercury, aluminium) in chicken and fish-based varieties were determined by ICP-MS due to the higher sensitivity required. Based on the results of elemental analysis, there was also some evidence of a lack of attention to micro-nutrient interactions in food. With reference to the guidelines, the RNI values for 6 to 9 month olds, all samples provided less than 20% of RNI values except for potassium (20%). In terms of the risk of exposure to toxicity, the concentration of non-essential elements in ready to feed products analysed were not considered to be of concern. With regard to the analyses of vitamins, a novel assay for the simultaneous quantitative determination of riboflavin (B2) and pyridoxine (B6) has been developed. The method involves a mild hydrolysis step, extraction of the supernatant by centrifugation followed by quantitative analysis using UHPLC. Separation of the two water soluble vitamins achieved is excellent and rapid - within one minute whilst the resultant sample is also LC-MS compatible. With respect to vitamin B analyses, despite wide individual differences between brands (p = 6.5e-12), no significant differences were observed in the levels of vitamin B6 between the meat and vegetable-based varieties (p = 0.7) per 100 g of commercial infant food. Vitamin B2 was not detected in any of the samples, where the detection limit was below 0.07μg/mL. In terms of the RNI of vitamin B6 for 6 - 9 month old infants, the complementary infant meal products analysed herein provided less than 15% of the RNI values with mean (SD) values of 12.87 (±4.46) % and 13.88 (±4.97) % for the meat- and vegetable-based recipes, respectively. The estimated total daily intake of vitamins B2 and B6 from the consumption of commercial complementary food was found to be satisfactory and in accordance with the DRVs. The intake of both vitamin B2 and B6 was estimated to be mainly derived from the consumption of formula milk which could be a cause of concern if the quality of an infant‘s milk diet is compromised by an inadequate or lack of supplemented milk intake. All the foregoing results suggest that commercial complementary infant foods on the UK market may not contain minimum levels of micronutrients required for labelling declaration of micronutrient content (Commission Directive 2006/125/EC). An attempt, therefore, was made to optimise the formulated version of the meat based infant food as a baseline and measure the post-process retention of its nutrient content after being subjected to different processing condition in terms of a combination of temperature and time. This was achieved by quantitative analysis of the post-process values of the nutrients in the optimised formula using the aforementioned analytical techniques. The results of this study indicates that careful formulation of the recipes, in the context of new product development, is important; the selection of high quality ingredients and the ratios in which they are used have a direct effect on the nutrient content of the final product. It also indicates that a carefully controlled temperature-time combination, pH, pressure and macroscopic conditions of processing (e.g. controlled leaching) are very important in reducing heat loss and improving the nutritional quality of the food product. This provides opportunities and scope for product optimisation, of ready to eat to eat infant foods, in order to improve their nutritional value