the obsession to increase farm productivity is taking a toll on the quality of fruits and vegetables. A us study shows nutrient value of 43 common crops has declined significantly over the past 50 years. The crops included 39 vegetables, three types of melons and strawberries.

Between 1950 and 1999 "there have been intensive efforts to breed new varieties that have greater yield... Emerging evidence suggests that when you select for yield, crops grow bigger and faster, but they don't necessarily have the ability to make or uptake nutrients at the same, faster rate,' says biochemist Donald Davis and others at the University of Texas at Austin in a paper included in the forthcoming issue of Journal of the American College of Nutrition (Vol 23, No 6).

They found the decline in nutrient value ranged from 6 per cent for protein to 38 per cent for riboflavin. Other nutrients studied included calcium, phosphorus, iron and ascorbic acid.

According to Davis, establishing meaningful changes in nutrient content over a 50-year period was challenging