This three-year Polish field trial fertilized carrots with iodine and selenium in different chemical forms. Selenate raised carrot selenium far more than selenite, to the point that a 100 g portion would supply five to six and a half times the adult recommended allowance. Selenite combined with iodine gave intakes near 100% of the allowance and a better iodine to selenium ratio. Selenium in carrot was present mainly in organic form, with selenomethionine the dominant measured compound.
Key numbers
- Fertilizer dose: 1 kg selenium per hectare, applied before sowing and as top-dressing (Abstract).
- A 100 g fresh portion from selenate plots: 500 to 650% of the adult selenium allowance; selenite plots: around or above 100% (Results, p. 9).
- Unfertilized control carrots: 8.4% (2012) to 41.2% (2014) of the selenium allowance per 100 g (Discussion, p. 14).
- Allowance used: 55 µg/day for adults; 60 to 70 µg/day in pregnancy and lactation (Discussion, p. 14).
- Share of leaf selenium present as selenomethionine: 18.4% to 96.3% across treatments and years (Results, p. 9).
Methods (brief)
Field plots received potassium iodide or iodate and sodium selenate or selenite alone or combined. Total selenium was measured by ICP-OES and selenomethionine by capillary electrophoresis. Absolute concentrations are reported in figures only.
Evidence fitness
Supports the point that the chemical form of selenium fertilizer strongly changes crop selenium, and that selenate can overshoot dietary targets. It is a controlled trial, not a survey of carrots on sale.
Limitations
One cultivar and site; detection limits for selenium are not stated; concentration values are available only graphically.
Related evidence
Update history
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