Effects of Selenium Fertilization on the Selenium Content of Selected Finnish Fruits and Vegetables

Abstract

In order to raise the selenium (Se) content of Finnish foods all agricultural and horticultural multinutrient fertilizers have been supplemented with sodium selenate since autumn 1984. This intervention has affected practically all agricultural products in Finland. The Se content of 16 fruits and vegetables was determined by electrothermal atomic absorption spectrophotometry. The selenate supplemented fertilization has clearly increased the Se content of most vegetables, with onion and the cruceiferous vegetables (cabbages, broccoli and swede) showing the highest increments; fruits are still low in Se. The mean Se values (mg/kg dry matter) were potato 0.07, carrot 0.07, swede 0.18, white cabbage 0.23, chinese cabbage 0.35, broccoli 0.75, lettuce 0.03, spinach 0.11, rhubarb 0.05, onion 0.25, pea 0.23, tomato 0.03, cucumber 0.13, apple 0.01, strawberry 0.02, and black currant 0.04. The Se levels for a single food type varied considerably, perhaps reflecting differences in fertilization practices. The present per person intake of Se in Finland is about 4 .mu.g/d from vegetables and 0.1 .mu.g/d from fruit. Together fruits and vegetables are responsible for 3% of the estimated total Se intake.