Fibre rich diet results in zinc, copper and magnesium deficiencies

This study was published in the Journal of the Trace Elements in Medicine and Biology 1996 Jun;10(2):68-76

Study title and authors:
Zinc, copper and magnesium absorption from a fibre-rich diet.

Knudsen E, Sandström B, Solgaard P.
Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/8829129?dopt=Abstract

This study investigated the effect of a high-fibre and high-phytate diet on levels of zinc, copper and magnesium. The study lasted for 21 days and included eight healthy subjects who were given a diet of conventional foods that included 1 mmol phytic acid, 29 g dietary fiber, 140 mumol zinc, 13 mumol copper, and 9 mmol magnesium per 2,415 calories.

The study found:
(a) The subjects levels of zinc decreased by 7 mumol.
(b) The subjects levels of copper decreased by 5 mumol.
(c) The subjects levels of magnesium decreased by 3 mmol.

The study reveals that a fibre-rich diet is associated with a net loss of the nutrients zinc, copper and magnesium.