Brown rice decreases iron availability of rice-based meals

Abstract

Brown rice is high in phytate and dietary fiber which are known as inhibitor of iron absorption. The objective of this study was to investigate the influence of brown rice on the iron availability of rice-base meals. Three different meals were designed for the study. Meal 1 was a rice-vegetable meal with a high tannic acid content. Meal 2 was a rice-vegetable meal with a high ascorbic acid content. Meal 3 was a rice-vegetable-pork meal; the ingredients were the same as for Meal 2 with 60g of pork added. Each meal contained about 5 mg total iron and was composed of 60g of rice. Of the different rice types, white, brown or white-brown mixed (1:1), the same quantities were replaced in each meal to study the influence on iron availability. The iron availability was measured by in vitro method and presented as dialyzable iron. The result showed that the percentage of dialyzable iron of total iron in the brown rice and mixed rice-based meals were lower than the white rice meal. The percents decrease in the brown rice were of 28-38% from the white rice meal while that in the white-brown mixed rice meal were 6-26% from the white rice meal. Variations in the decrease depended on inhibitors and enhancers in the study meal sets. The brown rice meals with higher iron absorption enhancers (Meal 2 and 3) were less influenced than the meal with a high inhibitor content (Meal 1)