Higher iron pearl millet (Pennisetum glaucum L.) provides more absorbable iron that is limited by increased polyphenolic content
Research
Nutrition Journal 2015, 14:11Â
doi:10.1186/1475-2891-14-11
Published: 23 January 2015
Abstract (provisional)
Background
Our objective was to compare the capacity of iron (Fe) biofortified and standard pearl
millet (Pennisetum glaucum L.) to deliver Fe for hemoglobin (Hb)-synthesis. Pearl
millet (PM) is common in West-Africa and India, and is well adapted to growing areas
characterized by drought, low-soil fertility, and high-temperature. Because of its
tolerance to difficult growing conditions, it can be grown in areas where other cereal
crops, such as maize, would not survive. It accounts for approximately 50% of the
total world-production of millet. Given the widespread use of PM in areas of the world
affected by Fe-deficiency, it is important to establish whether biofortified-PM can
improve Fe-nutriture.
Methods
Two isolines of PM, a low-Fe-control (“DG-9444?, Low-Fe) and biofortified (“ICTP-8203
Feâ€,High-Fe) in Fe (26mug and 85mug-Fe/g, respectively) were used. PM-based diets
were formulated to meet the nutrient requirements for the broiler (Gallus-gallus)
except for Fe (Fe concentrations were 22.1+/-0.52 and 78.6+/-0.51mug-Fe/g for the
Low-Fe and High-Fe diets, respectively). For 6-weeks, Hb, feed-consumption and body-weight
were measured (n=12).
Results
Improved Fe-status was observed in the High-Fe group, as suggested by total-Hb-Fe
values (15.5+/-0.8 and 26.7+/-1.4mg, Low-Fe and High-Fe respectively, P0.05). DMT-1,
DcytB, and ferroportin mRNA-expression was higher (P0.05) and liver-ferritin was
lower (P0.05) in the Low-Fe group versus High-Fe group. In-vitro comparisons indicated
that the High-Fe PM should provide more absorbable-Fe; however, the cell-ferritin
values of the in-vitro bioassay were very low. Such low in-vitro values, and as previously
demonstrated, indicate the presence of high-levels of polyphenolic-compounds or/and
phytic-acid that inhibit Fe-absorption. LC/MS-analysis yielded 15 unique parent aglycone
polyphenolic-compounds elevated in the High-Fe line, corresponding to m/z =431.09.
Conclusions
The High-Fe diet appeared to deliver more absorbable-Fe as evidenced by the increased
Hb and Hb-Fe status. Results suggest that some PM varieties with higher Fe contents
also contain elevated polyphenolic concentrations, which inhibit Fe-bioavailability.
Our observations are important as these polyphenols-compounds represent potential
targets which can perhaps be manipulated during the breeding process to yield improved
dietary Fe-bioavailability. Therefore, the polyphenolic and phytate profiles of PM
must be carefully evaluated in order to further improve the nutritional benefit of
this crop.