Fortification risks error and toxicity

Both infant formula and cow's milks are routinely fortified with vitamin D. Product standards and food regulations are in place to protect the public from error, but an outbreak of vitamin D intoxication1 in a Boston community demonstrates that close monitoring is needed. The source of the outbreak was determined to be excessive fortification of milk and led to an investigation into the actual levels of vitamin D found in fortified milk and infant formula compared to those reported on the labels.

Using high-performance liquid chromatography (the same technique as used by the infant formula industry) researchers Holick et al. found major discrepancies between amounts reported on the labels and amounts actually found in the products.

Infant formula:

  • Seven (70 per cent) of the 10 samples tested contained more than 200 per cent of the quantity stated on the label.
  • The sample with the highest level contained 419 per cent of the amount indicated on the label.
  • None of the infant formula samples tested contained less than the amounts indicated.

The authors concluded, "Milk and infant formula preparations rarely contain the amount of vitamin D stated on the label and may be either underfortified or overfortified. Since both underfortification and overfortification are hazardous, better monitoring of the fortification process is needed."

1. Jacobus, C.H. et al. Hypervitaminosis D associated with drinking milk. N. Engl. J Med 326:1173-1177,1992 BACK

2. Holick, M. F. et al. The vitamin D content of fortified milk and infant formula. N Engl J Med 326: 1178-1181, 1992

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