The poorer bioavailability of iron and zinc from plant foods and the lower content of the latter in vegetarian diets have raised questions about the impact of substituting soyfoods for animal products on iron and zinc status.1,2 Because relatively little red meat is needed to satisfy iron and zinc biological requirements, this issue is germane primarily only to non-meat eaters.3 To examine the impact of soy on mineral status, a 10-week randomized clinical trial was conducted by researchers from Iowa State University. The design of the study called for young, premenopausal, women to consume daily either two to three servings of soyfoods (n=31) or non-soyfoods (n=32) matched for the type of food consumed; e.g., soy burgers and soymilk replaced hamburgers and dairy milk. Subjects ate their meals 3 days/week at the research unit and carried out frozen meals (soy or control) to consume at home the other days. Results showed there were no statistically significant effects of soy on urinary zinc and serum zinc, hemoglobin and iron, and transferrin saturation.

REFERENCES
1) Sandberg AS. Bioavailability of minerals in legumes. Br J Nutr 2002;88 Suppl 3:S281–5.
2) Hunt JR. Moving toward a plant-based diet: are iron and zinc at risk? Nutr Rev 2002;60:127–34.
3) Johnson JM, Walker PM. Zinc and iron utilization in young women consuming a beef-based diet. J Am Diet Assoc 1992;92:1474–8.

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