Absorption of iron from foods has been reported to be inhibited by
various factors including some diet components. Fiber from different
sources has been observed to bind ferrous iron. This may be the reason
for iron deficiencies observed in populations that consume diets high in
non-digestible materials.
The effect of different levels of fiber from corn tortillas and cooked
beans on iron availability in the rat was studied. Iron-depleted rats
were fed test diets containing different levels of iron and fiber and the
diets were tested for their hemoglobin repletion ability. Estimation of
the neutral detergent fiber (NDF) in corn tortillas and cooked beans and
the soluble and ionizable iron in the test foods and diets were also
determined.
Corn tortillas contained 6.53% NDF. Raw beans contained 5.80% NDF
and increase to 15.75% upon cooking. In cooked beans, 60.16% of the
total iron is in the insoluble form while only 20.3% of the total iron in
corn tortillas is insoluble.
The mean relative biological value (RBV) for the test diets was
55.0 ± 19.0% with values ranging,from 40.41 ± 12.50% to 64.34 ± 11.10%
compared to that of ferrous sulfate (100% available). Fiber or iron
level had no significant effect on iron availability, however, a ratio
of 1.78 of corn tortilla to cooked beans showed the highest degree of
iron availability.
Percent efficiency of the test diets to incorporate iron into
hemoglobin ranged from 11.70 ± 1.4% for a diet containing 25 ppm iron and
15% NDF to 25.61 ± 6.10% for 35 ppm iron, 10% NDF diet. The control
diet containing 30 ppm ferrous sulfate had a 43.0 ± 8.7% efficiency.
Percent efficiency seems to show less variability in the determination
of iron availability from foods than RBV.
A significant correlation (p < 0.01) between soluble iron at pH 1.35
in vitro and percent efficiency was observed. This method could be used
to predict iron availability for different foods. / Graduation date: 1982
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26000 |
| Date | 23 June 1981 |
| Creators | Garcia-Lopez, Jesus Salvador |
| Contributors | Wyatt, C. Jane |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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