Is nutritional functional diversity in the rural food and nutrition system associated with food security and nutrient adequacy? A case study of rural areas of Zahedan district, Iran

Background An overlooked problem in food and nutrition system analysis is assuring adequate diversity for a healthy diet. Little is known about nutrient diversity in food and nutrition systems and how it transmits to dietary diversity. Nutritional functional diversity (NFD) is a metric that describes diversity in providing nutrients from farm to market and the consumption level. The objective of this study is to determine the NFD score at different stages of the rural food and nutrition system, including household's agricultural and home production, domestic food processing, purchased food, and diet. It also aims to explore the association between NFD and nutrient adequacy, food security, and anthropometric indicators. Methods A cross-sectional study was conducted on 321 households in 6 villages of Zahedan district. The NFD score was measured at three subsystems (production, processing, and consumption) of the food and nutrition system. Household food security, mean adequacy ratio (MAR), and anthropometrics of the household's head were measured to assess the association between NFD and food and nutrition indicators. Linear and bivariate statistical techniques were applied to study the associations between variables. Results In the rural food and nutrition system, the food purchased from the city plays the main role in the households NFD score. Their contribution to total NFD was twice that of the food items purchased from the village. The NFD score of homestead production and households food processing was found to be five times less than those of food purchased from cities. The food insecure households had significantly lower NFD scores for food purchased from the city and higher NFD scores for purchased food items from the rural market and native wild vegetable consumption. A strong and positive relationship was observed between NFD of food items purchased from the city and households'MAR. No significant association was found between the NFD score of homestead production, processing, and dependent variables, i.e. food insecurity, MAR, and household head anthropometrics. Conclusion NFD score, as a relatively new metric, could help in determining diversity from farm to diet and identifying the gaps to plan appropriate interventions for improving diversity in the local food system.