Rosalind S. Gibson

Zinc Nutrition in Developing Countries

Recently the United Nations has urged that priority should be given to developing programmless industrialized countries to prevent deficiencies of iodine, vitamin A, and Fe (United Nations, 1991). Nutritional Fe deficiency is associated with plant based diets which contain high levels of dietary fibre and phytate, components known to inhibit nonhaem Fe absorption, and low levels of flesh foods, rich sources of readily available haem iron (Monsen, 1988). Such plant based diets will also induce Zn deficiency. The consequences of Zn deficiency on human health in developing countries, however, have not yet been recognized. This is unfortunate because even mild Zn deficiency may contribute to pregnancy complications, low birth weight, impaired immune competence, maternal and infant mortality and morbidity, and growth failure in infancy and childhood (Swanson & King, 1987; Hambidge, 1989; National Academy of Sciences, 1991 ; United Nations, 1991). Hence Zn deficiency may have far reaching consequences on maternal, infant, and child health in many developing countries.

[Phytate][calcium]/[zinc] ratios in Asian immigrant lacto-ovo vegetarian diets and their relationship to zinc nutriture

Abstract Lacto-ovo vegetarians often have low zinc intakes coupled with concomitant high intakes of dietary fiber, phytate and calcium. The latter two dietary components appear to exert a synergistic inhibitory effect on zinc absorption. In this study 30 1-day diet composites were prepared for analysis from 3-day weighed diet records completed by 112 Asian immigrants consuming predominantly lacto-ovo vegetarian diets and compared with 30 omniverous diet composites. Analysed mean (±S.D.) daily intakes were: energy (kcal) 1892±445, calcium (mg) 1093±467, zinc (mg) 8.5±4.5, phytate (mg) 1487±791, neutral detergent fiber (g) 26.8±13.2. Median phytate: Zn molar ratio for Punjabi diets was 17.7 (range=5-50) and median [phytate][Ca]/[Zn] molar ratio was 475.4 (range=48-1150) compared with median values of 8.3 and 130.9 respectively for omniverous diets. Thirty-seven percent of the Punjabi diets had phytate:Zn ratios>20 and 80% had [phytate][Ca]/[Zn] ratios>200, levels shown to jeopardize zinc status in man. Thirty-two percent of the Punjabi subjects had low serum zinc levels (ie

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.,

Erythrocytes, erythrocyte membranes, neutrophils and platelets as biopsy materials for the assessment of zinc status in humans.

During a controlled zinc depletion-repletion study, fifteen men aged 25.3 (SD 3.3) years were fed on a low-Zn diet with high phytate:Zn and phytate x calcium:Zn molar ratios for 7 weeks, followed by a 2 week repletion period when 30 mg supplemental Zn/d was given. Changes in plasma, urine, and hair Zn concentrations, taste acuity, and cellular immune response confirmed the development of mild Zn deficiency. Zn concentrations in neutrophils, platelets, erythrocytes and erythrocyte membranes, mean platelet volume, and activities of alkaline phosphatase (EC 3.1.3.1) and alpha-D-mannosidase (EC 3.2.1.24) in neutrophils did not respond to changes in Zn status. In contrast, alkaline phosphatase activity in erythrocyte membranes showed a significant decline which was consistent in all subjects (nmol product formed/min per mg protein; baseline v. 7-week Zn depletion, 0.656 (SD 0.279) v. 0.506 (SD 0.230), at 7 weeks; P < 0.05); neutral phosphatase activity remained unchanged. Alkaline phosphatase activity in erythrocyte membranes may be a potential index of Zn status in humans.

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...

Dietary intakes of adolescent females consuming vegetarian, semi-vegetarian, and omnivorous diets

PURPOSE To determine the energy and nutrient intakes of some omnivorous and vegetarian female adolescents to compare their risk for nutrient inadequacies. METHODS A convenience sample of 78 lacto-ovo-vegetarians (LOV), 15 semi-vegetarians (SV), and 29 omnivorous (OM) females aged 14-19 years completed three-day weighed records from which mean intakes and major food sources of energy, nutrients, and dietary fiber (as nonstarch polysaccharides (NSP)) were calculated. RESULTS Mean daily intakes for energy and most nutrients were comparable for the three groups although LOV had higher intakes (p < 0.01) of NSP, copper, and manganese. Lacto-ovo-vegetarians consumed (g/d) less dairy products, flesh foods, and sweets but more legumes, nuts, and vegetables. Major food sources were cereal products for energy, most nutrients, NSP, dairy products for calcium, and fruits and vegetables for vitamin C. More LOV and SV had energy intakes less than two-thirds of Canadian recommendations, and higher probability estimates of inadequacy for protein, calcium, iron, zinc, and riboflavin than OM. Fewer LOV (35%) than SV (53%) and OM (41%) had diets with less than 30% energy from fat. CONCLUSIONS LOV and SV were more at risk for nutrient inadequacies than OM, although about 33% of OM were also at risk for inadequate intakes of iron and zinc.

Dietary phytate × calcium/zinc millimolar ratios and zinc nutriture in some Ontario preschool children

Millimolar ratios of phytate/Zn, Ca × phytate/Zn, and Ca × phytate/Zn per 4.2 MJ were calculated from 3-d weighed-food records collected from 62 male (M) (mean age: 58±7 mo [mean±SD]) and 44 female (F) (mean age: 58±6 mo) preschool children from Southern Ontario. Food-composition values for phytate were based on laboratory analysis and the literature. No gender differences existed for median millimolar ratios of phytate/Zn (median: M, 5.3; F, 5.3), and Ca × phytate/Zn per 4.2 MJ (M, 68.1; F, 59.5), but median intakes of phytate (M, 399; F, 333 mg/d) and median millimolar ratios of Ca × phytate/Zn (median: M, 102.1; F, 72. 3;p<0.01) were higher for boys than for girls. Of the children, only two (1M, 1F) and 22 (17 M, 5F) had millimolar ratios of phytate/Zn and Ca × phytate/Zn per 4.2 MJ, respectively, that were above critical values. Millimolar ratios of Ca × phytate/Zn (p=0.06) and Ca × phytate/Zn per 4.2 MJ (p=0.05) were higher in boys with hair zinc <1.07 μmol/g v≥1.07 μmol/g. Analysis of variance showed that height was influenced by an interaction between millimolar ratios of Ca × phytate/Zn per 4.2 MJ and sex (p=0.0007), when age and midparent height were treated as covariates. Results suggest that dietary Ca × phytate/Zn millimolar ratios, when expressed per 4.2 MJ, influenced the zinc nutriture of these Southern Ontario boys.

Chromium, selenium, and other trace element intakes of a selected sample of Canadian premenopausal women.

Daily Cr, Se, Ag, Cs, Rb, Sb, and Sc intakes of 84 Canadian women aged 30.3±6.1 yr (mean±SD) living in a University community and consuming self-selected diets were determined by analyses of 1-d food composites collected by the subjects. Aliquots of the homogenized food composites were freeze-dried and then analyzed by instrumental neutron activation procedures following irradiation for 72h. In all cases, trace element concentrations in the food composites were non-Gaussian. Median daily intakes were: Cr, 47 μg; Se, 74 μg; Ag, 7.1 μg; Cs, 4.4 μg; Rb, 1.5 mg; Sb 2.0 μg; and Sc, 0.38 μg. Sixty percent and 24% of the subjects received daily Cr and Se intakes, respectively, below the US Food and Nutrition Board safe and adequate range. High Cr density diets were associated with a significantly higher consumption of cheese and dry legumes and nuts (p<0.05). In the high Se density diets, intakes of grain products and breakfast cereals were significantly higher (p<0.05), and intakes of potatoes, table fats, total fat, saturated fat, and oleic acid were significantly lower (p<0.05) compared to the low Se density diets. The low daily Cr intakes evident in this study may be cause for concern in view of the increasing evidence that women may be at greater risk for deficiency of Cr than men because of Cr depletion during pregnancy.

Trace element intakes of women

1. Energy, protein, zinc, copper, manganese, selenium and dietary fibre intakes of 100 pre-menopausal women (mean age 30.0 +/- 6.1 years) from a university community, and consuming self-selected diets, were calculated using 3 d dietary records and food composition values. Subjects also collected a 24 h food composite during the 3 d record period for analysis of Zn, Cu and Mn by atomic absorption spectrophotometry. Daily analysed intakes were compared with those calculated from the corresponding record day. 2. Mean daily calculated intakes of energy, protein, Zn, Cu, Mn, Se and dietary fibre were 7.54 +/- 1.61 MJ, 74 +/- 18 g protein, 10.1 +/- 3.3 mg Zn, 1.9 +/- 0.6 mg Cu, 3.1 +/- 1.5 mg Mn, 131 +/- 53 micrograms Se, 19.4 +/- 6.6 g dietary fibre. 3. Major food sources for each of the trace elements were (%): Zn meat + substitutes 43, dairy products 23.7; Cu breads and cereals 22, vegetables 21; Mn breads and cereals 47, fruits 12, Se meat + substitutes 38, breads and cereals 30. 4. Highly significant correlations (P = 0.001) were noted for analysed intakes of Zn, Cu and Mn and those calculated from the corresponding record day. Mean calculated intakes were higher (%): Zn 138, Cu 142, Mn 121, than corresponding mean analysed intakes (P = 0.01). However, the mean nutrient densities (mg/MJ) were comparable: Zn analysed 1.2, calculated 1.4; Cu analysed 0.2, calculated 0.2; Mn analysed 0.4, calculated 0.4. 5. All subjects met the Canadian Dietary Standard (CDS) recommended level for Cu but 48% received less than the CDS for Zn, 6% obtaining less than two-thirds of this recommended level. Daily Mn and Se intakes were similar to recent values for North American diets.

Dietary chromium and effect of chromium supplementation on glucose tolerance of elderly Canadian women

Abstract Eighty-five free-living Canadian women 59–82 years of age participated in a double blind, 10 week study to determine the effect of supplementation with chromium (200 ug as CrC1 3 ) or placebo (distilled water) on glucose tolerance and serum immunoreactive insulin values. In addition, chromium intakes were measured by instrumental neutron activation analysis of 24 hour duplicate diet composites. Sixty-two percent of the women reported the use of medications which night affect glucose tolerance. No clear cut effects of chromium supplementation on glucose tolerance or serum insulin values were observed in these women. On the other hand, non-medicated subjects at risk of impaired glucose tolerance (i.e., having initial 2 hour glucose values>100 mg%) showed a significant (p=0.03) mean decrease in 2 hour glucose values after chromium supplementation. Such an effect was not observed in women with initial 2 hour glucose values after glucose challenge