Basic human nutrition requirements and dietary diversity in rice-based aquatic ecosystems

Abstract

The human organism requires a diverse diet in order to meet its nutrient requirements. In the agriculture sector, dietary energy supply had long been a proxy for adequate nutrition. Thus, one guiding principle of the green revolution was to supply dietary energy with the expectation that the nutrients would naturally follow. This has proved false. FAO calculates that there are 840 million undernourished people (FAO, 2000–2005c), yet there are billions with micronutrient deficiencies, more than half of whom have at least adequate energy intakes (FAO, 2004). Rice, and any starchy staple, is capable of providing all the energy required—but dietary diversity is necessary to provide the full range of nutrients. A rice-based aquatic ecosystem is a particularly rich source of biodiversity and—by extension—of dietary diversity. Easily measured and documented nutrient deficiencies include vitamin A, several B vitamins, calcium, iron, zinc, iodine, sulphur-containing amino acids and lysine, and fatty acids of the n-3 series. Recent studies have suggested that the rich utilized aquatic biodiversity in the rice-based ecosystems of Laos, Cambodia, China and Viet Nam could supply most of these nutrients (Halwart, 2003; Halwart and Bartley, 2005). Yet these populations suffer a high rate of micronutrient deficiencies and problems related to nutritional status such as low birth weights, high maternal and infant mortality, and stunting, wasting and underweight in children (FAO, 2005b; Meusch et al., 2003). The contributions to nutrition from these ecosystems are often unrecognized and unacknowledged by researchers, and are often under-appreciated by the local people. Foods outside the formal economy are not included in FAO statistical databases (e.g. Food Balance Sheets, FAO, 2005a), nor have most nutrition surveys attempted to document the differentiation in foods consumed in fine-enough detail to assess the importance of these ecosystems for the nutrition of rural populations. Many food composition tables and databases fail to capture individual foods by variety/strain/breed, preferring instead to group foods generically. Nevertheless, there is an ever-increasing body of data showing that individual cultivars, strains, breeds of the same species can have markedly different nutrient contents (Kennedy and Burlingame, 2003; Huang et al., 1999), and recent studies show that rural people are capable of identifying foods from a genetic resource perspective (Kennedy et al., 2005). With increased attention to local aquatic ecosystems, both for food composition and consumption activities, the contribution of these aquatic species can be properly assessed and their importance to the nutrition of rural people can be established, and ultimately preserved. References