Discussion
chapattis
The zinc-biofortified potato contained ∼50% more zinc than the traditional variety; and, despite lower FZA from the biofortified potato, TAZ was 22.5% greater. A saturable dose–response relationship has been described for zinc, with a predicted maximum zinc absorption of 13 mg [Given the low levels of PA in potatoes, zinc in potatoes could have a higher bioavailability than that in cereals and legumes. PA chelates zinc in the gut and is the chief zinc bioavailability antagonist [The presence of PA in plant foods will inhibit the absorption of zinc, depending on the level of PA and the PA:zinc molar ratio. According to the Miller equation [The FZA from the meal prepared with zinc-biofortified potatoes (20.8%) was lower than the meal prepared with regular potatoes (25.5%). These values are very much higher than FZA from a 300 g meal of porridge prepared with 50-g biofortified wholewheat flour (total zinc content 3.6 mg, FZA 6.3%) and of a hydroponically biofortified wheat porridge served as chapattis with a cauliflower–potato sauce (total zinc content 4.0 mg, FZA 5.7%) [Taking into consideration the mean intake of potatoes in women of childbearing age from the same urban highland area of study (181 g/d) (unpublished data from 86 women of childbearing age, Liria-Domínguez MR), the biofortified potato meal would contribute 13% of the estimated average requirement (EAR) for zinc for women of childbearing age [The concentration of PA in the biofortified potatoes used in this study was about half that found in regular potatoes; a 500 g meal contained 113-mg PA compared with 210 mg in a 500 g meal of regular potatoes. These levels are low compared with daily intakes of 300–800 mg reported for mixed diets [Previous studies on biofortified food crops have evaluated the bioavailability of zinc in cereals and beans [Our study shows that biofortified potatoes supply a higher quantity of absorbable zinc than regular potatoes. The advantage of potatoes is that they have a relatively low-phytate content, their consumption is widespread, the quantity of potatoes eaten daily is high, and they have a relatively low cost and high acceptability. Physiologic requirements for zinc can be difficult to meet, especially in low-income populations with a limited variety of foods in their diet [