The Green Revolution, while successful in increasing staple crop yields and farm incomes, did not eradicate malnutrition. This has led to a focus on nutrition-sensitive agriculture (NSA), aiming to increase consumption of micronutrient-rich foods. This study examines integrated aquaculture-agriculture (IAA) systems, where aquatic and terrestrial foods are grown together, as a potential NSA strategy. The research questions whether IAA can enhance both economic and nutrient productivity, contributing to improved nutrition outcomes, particularly for smallholder farmers in resource-constrained environments. The importance of this study lies in its potential to provide empirical evidence for designing effective NSA programs that improve both the economic livelihoods of farmers and the nutritional status of their families and communities. By investigating the interplay between economic and nutritional outcomes in diverse IAA systems, the study offers valuable insights for policymakers and development practitioners seeking to improve food security and nutrition. The study's focus on smallholder farmers in southern Bangladesh is crucial because this population is particularly vulnerable to malnutrition and economic instability. Understanding their farming practices and their impact on nutrition is critical for developing targeted interventions to improve their well-being.

Existing research highlights the disconnect between increased staple crop production and persistent malnutrition, prompting calls for NSA approaches. NSA programs aim to address malnutrition determinants by promoting diverse, nutrient-rich diets. Studies suggest that increased farm production diversity can improve household nutrition, although income generation is also a significant factor. While some studies evaluate the impact of NSA interventions on dietary diversity, this study takes a supply-side approach, focusing on the nutrient productivity of farming systems. Previous work in Bangladesh has indicated positive associations between vegetable production in integrated aquaculture and dietary quality, although average per capita intake of key nutrients remained similar across households.

Data were collected from a representative survey of 721 farms in southern Bangladesh in December 2020 and January 2021, building upon a 2013 survey. The study examined 12 distinct IAA combinations, encompassing a wide range of aquatic and terrestrial food production practices. Data on production of 35 aquatic and 31 terrestrial foods were collected, along with food composition data to estimate productivity per hectare of energy, protein, and five key micronutrients (calcium, iron, zinc, vitamin A, and vitamin B12). Economic productivity was calculated as the annual value of food production (minus variable costs), while nutrient productivity was expressed in annual adult equivalents per hectare (AEs ha⁻¹). Ordinary least squares regressions were used to analyze correlations between food production and economic and nutrient productivity, controlling for factors like farm size, household demographics, and access to resources. The nutritional value of foods was calculated using the Food Composition Table for Bangladesh and data from Bogard et al. (2017) for aquatic foods. Adult equivalents (AEs) were calculated using recommended dietary allowances (RDAs) to express nutrient productivity relative to human nutritional requirements. Ethical considerations were addressed by obtaining necessary approvals from the Michigan State University Institutional Review Board. Data collection was facilitated by KoboToolbox. The sample represents the entire population of aquaculture farms in selected districts.

The study found that IAA systems combining fish and prawns with vegetables and fruits and rice were among the most economically productive and also had the highest productivity of energy, protein, iron, zinc, and vitamin A. Systems that included shrimp but lacked terrestrial food integration showed lower nutrient productivity despite relatively average economic productivity, highlighting the importance of integrating terrestrial crops. Rice provided a significant portion of energy and protein across systems, while aquatic foods were the primary calcium source. Vegetables and fruits were the main contributors of vitamin A. Regression analysis revealed that crustacean yields were most positively correlated with economic productivity, followed by carp yields. Okra, ground beans, and eggplant were positively correlated with protein, iron, and zinc productivity, while pumpkins, leafy vegetables, mangoes, and betel nuts were important vitamin sources. Coconuts showed a positive correlation with the productivity of most nutrients. While some economically valuable aquatic foods like crustaceans might lead households to purchase nutritious foods rather than produce them, integrating terrestrial foods enhanced the overall nutritional value and economic viability of diverse farming systems.

The findings demonstrate that integrated aquatic and terrestrial food production can significantly enhance both economic and nutrient productivity, supporting the development of nutrition-sensitive agricultural practices. The study highlights the importance of selecting appropriate combinations of aquatic and terrestrial food crops to optimize both economic returns and nutritional outcomes. The significant positive correlation between certain crops and various nutrients suggests strategies for promoting specific crop combinations for improved dietary quality. While the focus on supply-side factors is crucial for understanding the potential of IAA systems, future research could explore demand-side factors and household-level dietary changes further. The study underscores the need for integrated approaches considering both economic and nutritional aspects for developing sustainable and nutrition-sensitive food systems.

This study provides strong empirical evidence supporting the integration of aquatic and terrestrial food production as a key strategy for nutrition-sensitive agriculture. The results highlight the importance of species selection and combination for optimizing economic and nutrient productivity. This approach allows for the identification and promotion of culturally and agroecologically suitable food combinations that maximize nutritional outcomes. Future research could focus on optimizing yields of specific high-value, nutritious crops, investigating the impact on dietary diversity, and examining the effects of salinity on production in different farming systems.

The study is limited to a specific region in southern Bangladesh. The generalizability of findings to other contexts might be limited due to variations in climate, soil conditions, and consumer preferences. While the study considers several control variables, other unmeasured factors might influence the relationships observed. Future research could expand the geographic scope and investigate the long-term impacts of IAA systems on household nutrition and livelihoods.