Effect Of Inclusion Of Cabbage And Potatoes In The Maize And Beans Composite Meal On The Bioavailability Of Iron And Zinc By In-Vitro Method.
Abstract
The extent of bioavailability of iron and zinc from meals is of great health
concern since these. micronutrients play key role in mental performance and
immune response in' human beings. In this study the bioavailability of iron and
zinc from maize and bean composite was investigated and found to at 13% for
iron and 27. 7%for zinc. The inclusion of cabbage enhanced the bioavailability of
both to 98.8% and 83.9% respectively to the extent that the differences in the
concentrations of iron and zinc in the non-digested and digested samples were not
significant(iron, p=0.12 : Zinc, p=0.263). There was a significant difference
between concentration of iron and Zincin the basic mixture when non -digested
and digested were compared with p= 0.004 for iron and 0.012 for zinc
respectively. In the samples where cabbage was included, there were no
significant differences in the concentrations of iron and zinc between the nondigested
and digested (iron, p=0.12, zinc, p=0.263) an indication of high
bioavailability. The inclusion of potatoes reduced the bioavailability of iron and
zinc to 76.86 % and 38.9% respectively. This is due to matrix effect where the
potato introduces stronger-physico -chemical interactions. The composite with
maize, beans, cabbage and potaioes have a bioavailability of 76.2%, p= 0.249 for
iron and 71.76%, P = 0.405 [or zinc). This is an indication that cabbage has a
'higher enhancing effect than thepotatoes. The generally high bioavailability of
iron and zinc from a composite oj beans and maize can be due to the interaction
between the metal ions and tridentate amino acids in the beans where the chelate
formed enhances their bioavailability. This interaction increases mucosal
membrane permeability and lipo-solubility of the metal ions. The recommendation
is that dietitians should educate people on best combination of foods that will
enhance the bioavailability of not only iron and zinc but all micronutrients since
they are of health importance to pregnant and lactating mothers, young children,
adolescents and the elderly. Other alternatives include double fortification of salt
with iron and zinc and bio-fortification.