Commoditization of food systems, defined as the use of agricultural goods for sale rather than for home consumption, affects nutrition of rural families via economic, social and ecological mechanisms in addition to direct dietary effects. Broad-scale mechanisms include alterations in land tenure, increased stratification of wealth, widespread labor migration, urban bias, food price changes, disruption of traditional reciprocal social relations, and ecological changes accompanying commercial agriculture that may limit long-term food production. At the family level, the replacement of food with cash is often problematic as regards nutrition, due to low prices to producers, increased cash needs, the 'lumpiness' of earnings during the year, reduced decision-making power of women, and often decreased dietary diversity. Three case studies in Latin America and the Caribbean, from Peru, Jamaica, and Mexico, illustrate that commoditization tends to have a negative impact on nutrition in poor rural households. Although commoditization is theoretically advantageous on a national level by allowing the use of 'comparative advantage', in actuality its potential benefits are eroded by inequitable uses of foreign exchange. Commoditization is in essence a more efficient means by which to extract surplus value from small agricultural producers. While commoditization is a necessary component of economic growth, policies to safeguard health and nutrition and improve the status of women in development programs must be implemented within an overall strategy to meet basic needs of the population.