To analyze intra-household nutrient allocation, we examine the differences in expenditure elasticities across demographic groups within rural households, employing an asymmetric model along with data from the China Health and Nutrition Survey (CHNS) from 2004 to 2011. Our analysis reveals significant heterogeneity in household nutrient allocation: during periods of expenditure expansion, households prioritize the nutritional intake of vulnerable members, specifically children and the elderly, often at the expense of prime-age adults, particularly women. Conversely, during expenditure contraction, households shift strategies to protect the nutritional intake of prime-age adults. This asymmetry underscores the complexity of intra-household distribution and provides critical insights for designing nutrition security policies that account for economic volatility.