[Study on the contribution rate of follow-up formula to the nutrient intake of infants and young children aged 7-24 months in China].
Objective: To determine the contribution of follow-up formula (FUF) to the nutrient intake of 7-24-month-old infants and young children. Methods: The cluster random sampling method and the convenience sampling method were used in combination, and geographic and economic factors were taken into consideration. Four areas of China (Beijing, Hebei, Guangxi, Guangdong) were selected, with 120 infants chosen from each of these areas (half of which were 7-12 months old, and half were 13-24 months old). A dietary survey was completed by a continuous 24-hour weighing method over two days. Questionnaires were completed by their caregivers which included weighing the FUF and supplementary food given to the infant, and recording the frequency of breast feeding and any supplementary nutrients. A total of 518 questionnaires were distributed, and 472 questionnaires qualified for inclusion. Nutrient intake was calculated using the China food composition, infant formula food nutrient content and infant nutrition supplement brand-label information databases, and then the nutrient intake proportion (the percentage of estimated energy requirement (EER%), recommended nutrient intake (RNI%) or adequate intake (AI%)), and the contribution rate of FUF were analyzed. Results: A total of 472 infants were investigated (227 infants aged 7-12 months old, 245 infants aged 13-24 months old). The findings revealed that the median energy intake of 7- 12-month-old and 13- 24-month-old infants were 2 530.08 kJ and 3 445.48 kJ, respectively, which accounted for 85.18% and 94.14% of EER, respectively; and the median intake of protein reached 91.50% and 105.88% of their RNI/AI, respectively. For micronutrients, the median intake of vitamin B1, vitamin B2, niacin, vitamin E, potassium, zinc and manganese in 7- 12-month-old infants and vitamin B2, vitamin E, potassium, magnesium, iron and manganese in 13-24-month-old children accounted for 82.00% and 114.29% of RNI/AI (RNI%/AI%), respectively. The intake of vitamin B6, iron and selenium in 7-12-month-old infants and vitamin B1, vitamin B6, vitamin C, calcium and selenium in 13-24-month-old children was less than 80% RNI/AI. Furthermore, some nutrients showed higher intake levels, such as vitamin A, calcium, phosphorus and magnesium in 7-12-month-old infants and vitamin A and phosphorus in 13-24-month-old children, which were higher than 130% RNI/AI. In total, 40.53% (92) of infants aged 7-12 months and 52.65% (129) of children aged 13- 24 months were fed FUF as part of their diet, and its contribution rate to macronutrients was 29.69% for carbohydrates and 51.77% for fats, and to micronutrients was 2.04% for manganese and 74.24% for vitamin C. Conclusion: FUF contributes to the nutrient intake of infants and young children aged from 7-24 months old at different rates depending on the macronutrient or micronutrient analyzed.