http://www.fao.org/nutrition/food-composition/
Food composition data are the basis for almost everything in nutrition, and should receive more attention in agriculture to render our food supply more nutritious.
FAO coordinates the International Network of Food Data Systems (INFOODS), a worldwide network of food composition experts aiming to improve the quality, availability, reliability and use of food composition data.
Nutrient contents in foods can vary significantly because:
- of environmental, genetic and processing influences such as feed, soil, climate, genetic resources (varieties/cultivars, breeds), storage conditions, processing, fortification and market share;
- each country has its own consumption pattern resulting in country-specific foods, recipes and brand-name foods (commercial foods with the same brand-name can have varying composition due to taste or fortification regulations across borders)
- food biodiversity highly influences the composition of foods: nutrient values may vary up to 1000 times among different varieties of the same foods. This means that the nutrient content of foods can vary as much among foods as among varieties of the same food.
Therefore, each country has specific data needs as they have different compositions of their foods, even if some people think that foods have similar composition among countries due to globalization.