Although micronutrient deficiency is a global problem, the burden is not evenly shared within affected households. This review suggests that there are important non-linearities in relationships among food intake, sharing, and caring behavior within the household. Since micronutrient status relates to interactions among biological, social, behavioral, economic, and environmental processes, outcomes are not always predictable by age, gender, or location. Understanding such variability is crucial to identifying appropriate solutions. This review represents an exploratory first step toward unmasking population-specific variations that are important for better understanding the nature of micronutrient deficiencies and for improving the focus of public health action.