Historical variation in the mineral composition of edible horticultural products

Historical variation in the mineral composition of edible horticultural products was determined from UK and USA food survey data. From these data, it was possible to measure the variation in the mineral composition of edible horticultural products in general, and in edible horticultural products grouped as vegetables, fruits or nuts, in the 1930s and in the 1980s (or later) for both countries. Thus, the hypothesis that the mineral composition of edible horticultural products had altered since the 1930s was tested. The average concentrations of Cu, Mg and Na in the dry matter of vegetables, and the average concentrations of Cu, Fe and K in fruits decreased significantly between the 1930s and the 1980s in the UK. The same hypothesis was tested with comparable data from the USA, whose historical horticultural and consumer practices have paralleled those of the UK. Data from the USA showed that the average Ca, Cu and Fe concentrations in the dry matter of vegetables, and the average concentrations of Cu, Fe and K in fruits had decreased significantly since the 1930s. There were insufficient data to determine if the mineral composition of any single edible horticultural species had altered significantly over time either in the UK or in the USA. The nutritional implications of this study are discussed. Since horticultural products in general, and fruits and nuts in particular, are relatively small contributors of minerals to the average UK diet, historical changes in mineral composition are unlikely to be significant in overall dietary terms.