Consumption of fibre-rich wheat bread results in iron deficiency

This study was published in the European Journal of Nutrition 2005 Sep;44(6):334-40

 

Study title and authors:

A decrease in iron status in young healthy women after long-term daily consumption of the recommended intake of fibre-rich wheat bread.

Bach Kristensen M, Tetens I, Alstrup Jørgensen AB, Dal Thomsen A, Milman N, Hels O, Sandström B, Hansen M.

The Dept. of Human Nutrition, The Royal Veterinary & Agricultural University, Rolighedsvej 30, 1958, Frederiksberg C, Denmark. mbk@kvl.dk

 

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/15349738

The objective of the study was to measure the effects of long-term consumption of the recommended intake of fibre-rich wheat bread on the iron status of young healthy women with adequate iron stores. The study lasted for four months and included 41 healthy women, average age 24.8 years, who were provided daily with 300 grams of fibre-rich wheat bread, prepared (i) with or (ii) without phytase (an enzyme that reduces the phytic acid content in food) as a supplement to their habitual diet.

After four months, the study found:
(a) Levels of ferritin were significantly reduced in all women by an average of 27%. (Low ferritin levels lead to anaemia).
(b) Levels of haemoglobin were significantly reduced in all women by an average of 1.5%. (When a person has a low haemoglobin level, they may feel weak,tired, dizzy or cold).

The study indicates that consumption of the recommended daily intake of fibre-rich wheat bread (with high or low phytic acid concentrations) results in an impairment of iron status in women with initially sufficient iron stores.

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.

Zinc bioavailability from beef is about fourfold greater than from a high-fiber breakfast cereal.

This study was published in the American Journal of Clinical Nutrition 1993 Dec;58(6):902-7

 

Study title and authors:

Measurement of zinc bioavailability from beef and a ready-to-eat high-fiber breakfast cereal in humans: application of a whole-gut lavage technique.

Zheng JJ, Mason JB, Rosenberg IH, Wood RJ.

Mineral Bioavailability Laboratory, US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111.

 

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/8249876

This study compared the effects of beef and breakfast cereals on zinc absorption. The study included eight healthy adults who were given foods containing approximately 4 mg (61.2 mumol) zinc as either beef or a high-fiber, ready-to-eat breakfast cereal.

The study revealed that zinc absorption from the high-fiber breakfast cereal was 14.7%, whereas zinc absorption from beef was 55.1%.

The study demonstrates that zinc bioavailability from beef is about fourfold greater than from a high-fiber breakfast cereal.