Elaine L. Ferguson

Phytate, zinc, and calcium contents of 30 East African foods and their calculated phytate:Zn, Ca:phytate, and [Ca][phytate]/[Zn] molar ratios

Abstract Representative samples of 30 staple Malawian foods, raw and prepared “as eaten,” were analyzed for phytate using an anion-exchange method, and for calcium and zinc by flame atomic absorption spectrophotometry. Phytic acid contents expressed on a fresh weight (FW) basis ranged from 211–1089 mg/100 g for cereals and 166–1297 mg/100 g for legumes, to 4–97 mg/100 g for leaves, 10–59 mg/100 g for roots, and 11–25 mg/100 g for fruits. In general, leaves had the highest calcium content (81–514 mg/100 g FW), followed by kidney beans (90 mg/100 g FW), and dry pigeon peas (112 mg/100 g FW). The calcium content of other foods analyzed was relatively low. The zinc content of wild blight, cassava leaves, and okra leaves was comparable to that for the less refined cereals and legumes (i.e., > 1.0 mg/100 g FW), but higher than that of highly refined cereals, pumpkin leaves, chinese cabbage, and other foods analysed (i.e.,

Seasonal food consumption patterns and dietary diversity of rural preschool Ghanaian and Malawian children

Food intakes of rural Malawian (29F. 36M; 62 ± 10 mo) and Ghanaian (83F, 65M; 59 ± 10 mo) children were estimated at two seasons using 3‐day weighed records. Food patterns, dietary diversity, based on the number, and frequency of foods consumed, and major sources of energy and selected nutrients were examined. The total, and average number of food items consumed per day were lower in Malawi (62, 6.4 ± 1.4 per day) than in Ghana (70 ‐ 76. 7.5 ± 1.3 ‐ 8.0 ± 1.2 per day). More Malawian than Ghanaian children (25 and 46% versus 12 and 27%, depending on season) consumed 6 food items or less per day. Major energy sources were cereals (51–69%) in Malawi, and cereals (24–41%), and roots (24–37%) in Ghana; animal products contributed 3–7% of the energy. Dietary diversity was associated with intakes of energy (per kg BW) (r = 0.33–0.41; p < 0.02) in Malawi, the consumption of prestigious foods and snacks in both countries, and with purchased meals in Ghana. Hence, increased consumption of nutrient dense purchased m...

The validity of the 24 hour recall for estimating the energy and selected nutrient intakes of a group of rural Malawian preschool children

The validity of the 24‐hour recall (24 HR) for estimating group aggregate and individual daily energy, protein, calcium, iron, zinc and vitamin C intakes of 29 rural Malawian children (4–6 years) was assessed by comparing weighed record (WR) and 24 HR dietary data collected for the same day of food intake. There were no significant differences comparing group median energy and nutrient intakes estimated using the two techniques. The percentage differences between group mean intakes ranged from 1% (vitamin C) to 16% (Ca). In general, these differences were reduced when morning meal intakes were omitted to eliminate the systematic bias affecting estimates of porridge intake. Spearmans and intra‐class correlation coefficients ranged from 0.28 (vitamic C) to 0.55 (Zn), and from 0.14 (vitamin C) to 0.51 (Zn), respectively. Less than 35% of the nutrient intakes estimated using the 24 HR were within ± 10% of those estimated via the WR (range = 12% for vitamin C and Ca to 33% for protein), and over 50% of the sub...

The mineral content of commonly consumed Malawian and Papua New Guinean Foods

Abstract The calcium, phosphorus, zinc, copper, manganese, magnesium, sodium, and potassium contents of 44 Malawian foods and 18 Papua New Guinean foods were analyzed using flame atomic absorption spectrophotometry and X-ray fluorescence procedures. The mineral content (mg/100 g edible portion) of these foods ranged from trace amounts (maize flour) to 3292 (crabs) for Ca; 7 (sago) to 1702 (dry matemba) for P; 0.08 (sago) to 25.4 (usipa) for Zn; 0.01 (sago) to 3.0 (locust) for Cu; 0.03 (yam, pumpkin, duck egg) to 3.92 (tulip) for Mn; 6 (pancakes) to 259 (crabs) for Mg; trace amounts (cereals, sago) to 578 (crabs) for Na; 16 (sago) to 1397 (dry kidney bean) for K. Animal products had the highest content of most minerals analyzed. The mineral content of the dietary staples tended to below.

Dietary strategies for improving the zinc nutriture of rural, southern Malawian and Ghanaian children

Rural African children consuming plant‐based diets low in animal products are at risk for sub‐optimal zinc nutriture. Consequently, we investigated indigenous dietary strategies for inproving the zinc nutriture of rural southern Malawian and Ghanaian children. Seasonal dietary intakes, and the portion sizes of foods consumed by 4–6 year old Malawian and Ghanaian girls (n = 112) were determined from 3‐day weighed food records. The optimal combination of food items for enhancing zinc bioavailability was determined by comparing the zinc content, and the phytate‐to‐zinc molar ratio (PZ) of isocaloric meals and snacks consumed by these girls. The energy content and portion sizes of the recommended meals and snacks were based on actual average intakes. Results showed that in Malawi the amount of available zinc could be enhanced by using refined corn flour nsima or a non‐traditional fermented corn dough nsima with relishes prepared from small fish, and snacks with moderate to low PZ. In Ghana, fermented corn dou...

The selenium content of staple foods from Malawi and Papua New Guinea

Abstract Selected samples of raw and cooked staple foods from the Zomba district of Malawi, East Africa (n = 37), and the Wosera subdistrict of Papua New Guinea (n = 19) were analyzed for selenium by instrumental neutron activation analysis, using the short-lived 77Se ( t 1 2 = 17.4 s ) isotope. Food samples, previously dried and ground, were irradiated at a neutron flux of 5 × 1012 neutrons · CM−2 · s−1 using an irradiation/decay/count protocol of 30, 7, and 30 s, respectively. Selenium concentrations were determined by recording the net counts of the 162-keV γ rays emitted by 77Se within the samples. Selenium content was expressed per 100 g of raw or cooked edible portion, on a wet weight basis. Of the Malawian staple foods, animal products such as fish had the highest selenium concentrations (11.1 to 73.2 μg/ 100 g), followed by duck eggs (19.5 μg/ 100 g). Cereals had selenium concentrations ranging from 2.0 to 12.9 μg/100 g; legumes ranged from 0.7 to 6.4μg/100 g; fruits and vegetables were low (0.2 to 1.2 μg/100 g). The staple foods analyzed from Papua New Guinea were mostly plant-based and low in selenium ranging from 0.1 μg Se/100 g for sago to 3.3 μg/100 g for pumpkin tips. Breadfruit seeds, however, contained 10.7 μg Se/100 g. The selenium content of the Malawian foods resembled that of comparable foods grown in countries where the soil is low in selenium. The analyzed staple foods of Papua New Guinea were generally low in selenium.