Bakary Dibba

The calcium and phosphorus intakes of rural Gambian women during pregnancy and lactation

The Ca and P intakes of 148 pregnant and lactating women in a rural village in The Gambia, West Africa, have been estimated by direct weighing of food on a total of 4188 d. The Ca and P contents of local foods were determined by analysis of raw ingredients, snack foods and prepared dishes. Information about the contribution of mineral-rich seasonings was obtained. Efforts were made to discover unusual sources of Ca that might not be perceived as food by subject or observer. The main contributors to daily Ca intake were shown to be leaves, fish, cereals, groundnuts and local salt. Cows milk accounted for only 5% of Ca intake. Unusual sources of Ca were discovered, namely baobab (Adansonia digitata) fruit and selected earths, but these were consumed infrequently and their contributions to Ca intakes were small. Cereals and groundnuts were the main sources of P. Ca and P intakes (mg/d) were shown to average 404 (SD 110) and 887 (SD 219) respectively. Seasonal changes in the availability of leaves, cereals and groundnuts resulted in variations in Ca and P intakes. The rainy season was associated with increased Ca intakes (by 16%) but decreased P consumption (by 15%). No difference was observed in Ca intake between pregnant and lactating women but P intake in lactation was 11% higher than that in pregnancy during the post-harvest season. The implications of these low Ca intakes require investigation.

Vitamin D Status Does Not Influence the Breast-Milk Calcium Concentration of Lactating Mothers Accustomed to a Low Calcium Intake

Plasma 25‐hydroxy‐vitamin D and breast‐milk calcium concentration were measured at 3 months of lactation in 60 Gambian mothers accustomed to a low calcium diet, of whom 30 were consuming a calcium supplement and 30 were receiving a placebo, and in 48 British mothers. The plasma 25‐hydroxy‐vitamin D concentration of the Gambian women was not affected by either calcium supplementation (supplemented, 64. 4 ± 2. 5 nmol 1‐1; placebo, 64. 9 ± 3. 5 nmol l‐1; mean ± SE) or season. The British average was lower (53. 9 ± 3. 0 nmol 1‐1, p= 0. 004), owing to marked seasonal effects. The breast‐milk calcium concentration was lower in The Gambia (supplemented, 5. 38 ± 0. 13 mmol 1‐1; placebo, 5. 10 ± 0. 13mmol 1‐1; British, 6. 93 ± 0. 15 mmol 1‐1, p < 0. 0001). There was no relationship between plasma 25‐hydroxy‐vitamin D and breast‐milk calcium concentration in any group. There was no trend towards lower breast‐milk calcium concentration in women with vitamin D status towards the bottom of the normal range or in British women during the winter. This study provides no support for the hypothesis that breast‐milk calcium concentration is influenced by vitamin D status or that lactating women with a low calcium intake are at particular risk of vitamin D deficiency.

An investigation of ethnic differences in bone mineral, hip axis length, calcium metabolism and bone turnover between West African and Caucasian adults living in the United Kingdom.

The aim of the study was to investigate factors relating to calcium and bone metabolism which might explain the low incidence of osteoporotic fracture among Africans. Adult bone mineral status, hip axis length and biochemical indices were investigated in 20 Caucasians (10 male, 10 female) and 19 Gambians (12 male, 7 female) living in the UK. Bone mineral content (BMC), bone mineral density (BMD) and BMC adjusted for bone area, body weight and height (size-adjusted BMC) were measured for the whole-body, lumbar spine, femoral neck, trochanter, radius shaft and radius wrist using dual-energy X-ray absorptiometry. There were no significant differences in whole body or regional BMC; values tended to be lower in the Gambians. Gambian men had higher size-adjusted BMC at the femoral neck (Gambian-British = 21%, 95% CI = 6 to 36%, p < 0.01), associated with a smaller bone area (Gambian-British = -11%, 95% CI = -20 to -2%, p = 0.02). BMD was affected similarly. No other significant differences in BMD or size-adjusted BMC were observed. Gambians had shorter hip axis length (Gambian British, after accounting for sex, = -5%, 95% CI = -9 to -1%, p = 0.02). There were no significant differences in bone turnover (osteocalcin, bone isoenzyme of alkaline phosphatase, urinary deoxypyridinoline) or calciotropic hormone levels (parathyroid hormone, 1,25-dihydroxyvitamin D, calcitonin). Gambian men had lower 25-hydroxyvitamin D concentrations (Gambian = 26.3 SD 12.0 nmol/L, British = 55.5 SD 13.9 nmol/L, p < 0.0001), a difference not seen among the women. Gambian men and women excreted significantly less phosphate and potassium than British subjects by 30-60%; urinary calcium and sodium excretion were similar in the two groups. This study revealed few ethnic differences that could account for the disparity in osteoporotic fracture rates between Africans and Caucasians, with the possible exception of anatomical differences in the hip.

The effect of long-term calcium supplementation on indices of iron, zinc and magnesium status in lactating Gambian women

The effect of long-term supplementation with CaCO3 on indices of Fe, Zn and Mg status was investigated in a randomized, double-blind intervention study of sixty lactating Gambian women. The supplement contained 1000 mg Ca and was consumed between meals 5 d/week, for 1 year starting 1.5 weeks postpartum. Compliance was 100%. Plasma ferritin concentration, plasma Zn concentration and urinary Mg output were measured before, during and after supplementation at 1.5, 13, 52 and 78 weeks postpartum. No significant differences in mineral status were observed at any time between women in the supplement and placebo groups. Analysis of the longitudinal data series showed that plasma ferritin and Mg excretion were characteristic of the individual (P < 0.001). Within individuals, ferritin concentration was higher at 1.5 weeks postpartum than later in lactation (P = 0.002). Plasma Zn concentration was lower at 1.5 weeks postpartum than at other times (P < 0.001), an effect which disappeared after albumin correction. Low plasma concentrations of ferritin and Zn indicated that the Gambian women were at high risk of Fe and Zn deficiency. Measurements of alpha 1-antichymotrypsin suggested that the results were not confounded by acute-phase responses. The results of the present study indicate that 1000 mg Ca as CaCO3 given between meals does not deleteriously affect plasma ferritin and Zn concentrations or urinary Mg excretion in women who are at risk of Fe and Zn deficiency.

The effect of prepubertal calcium carbonate supplementation on the age of peak height velocity in Gambian adolescents

Background: Limited evidence suggests that calcium intake before puberty influences adolescent height growth and the timing of puberty. Such an effect might be particularly marked in populations in whom low calcium intake, stunting, and delayed puberty are common. Objective: The objective was to test whether 12 mo of calcium supplementation at age 8–12 y to increase intakes toward international recommendations had long-term effects on adolescent growth and pubertal development in rural Gambian children. Design: This was a longitudinal study of 160 Gambian boys (n = 80) and girls (n = 80) who had participated in a 12-mo, randomized, double-blind, placebo-controlled, calcium carbonate supplementation trial (1000 mg Ca/d, 5 d/wk) at age 8–12 y. Anthropometric measures were made every 1–2 y until age 21–25 y; pubertal status and menarche data were collected. Repeated-measures ANCOVA and Superimposition by Translation and Rotation Method (SITAR) growth models were used to assess the effects of treatment. Results: In boys, midadolescent height growth was advanced in the calcium group, which resulted in greater stature at a mean age of 15.5 y (mean ± SEM: 2.0 ± 0.8 cm; P = 0.01) and an earlier age of peak height velocity by 7.4 ± 2.9 mo. Subsequently, the calcium group stopped growing earlier (P = 0.02) and was 3.5 ± 1.1 cm shorter (P = 0.002) at a mean age of 23.5 y. Weight and midupper arm circumference paralleled height. No significant effects were observed in girls, but a sex-by-supplement interaction on height growth could not be confirmed. Conclusion: Calcium supplementation of boys in late childhood advanced the age of peak height velocity and resulted in shorter adult stature in a population in whom low calcium intakes and delayed puberty are common. This trial was registered at isrctn.org as ISRCTN28836000.

Breast-milk amylase activity in English and Gambian mothers: effects of prolonged lactation, maternal parity, and individual variations.

ABSTRACT: Breast milk contains an amylase that may contribute to carbohydrate digestion in infants. The aim of our study was to determine whether mothers differ in their breast-milk amylase activity and whether the activity is maintained during prolonged lactation. This was investigated by measuring breast-milk amylase activity by hydrolysis of maltotetraose in 63 English mothers of parity 1-5 and 107 Gambian mothers of parity 1-12 who were at various stages of lactation (0.5-27 mo). Amylase was present in all samples and showed a great range of activity from 0.08 to 3.53 IU/mL. Amylase activities did not vary during a feed nor over 24 h, and each mother had a characteristic level of activity in her milk. Amylase activity was higher in the 1st trimester of lactation, and decreased by 35% (p < 0.001) to a plateau at 6-27 mo. Gambian mothers of very high parity (parity 11-12) had 54% of the activity of primiparous mothers (p < 0.001), after adjustment for stage of lactation. Using community data on milk volume, the estimated breast-milk amylase intake by breast-fed children was on the order of 800-1000 IU/24 h in the 1st trimester and 400 IU/24 h in the 2nd year of lactation. Individual measurements emphasized the great differences in this intake among children of the same age. Our study showed that breast milk is an important source of amylase both in developed and developing countries, but there are large variations in intake among children.