Biomedical subjects
Publications and source records attributed to R H Glew.
Phase angle, an impedance parameter used for nutritional assessment, is reflective of the capacitance properties of cell membranes. We have shown a significant correlation between the proportions of specific n-3 polyunsaturated fatty acids in the serum phospholipids of Nigerian children with sickle cell disease and their phase angles determined by bioelectrical impedance analysis.
Explore the source record for details and available documents.
Ultrasound analysis of the calcaneus and serum markers of bone turnover were used to examine the bone status of healthy Nigerian women who reside in an area of the world where dietary calcium intake is generally low and estrogen replacement therapy is not widely available. A total of 218 women (108 premenopausal and 110 postmenopausal) between the ages of 16 and 95 years were enrolled in the study. Broadband ultrasound attenuation (BUA) and speed of sound velocity (SOS) were measured and used to calculate the stiffness index (SI) of the calcaneus. In this cross-sectional study, the Nigerian women exhibited a marked age-dependent decline in SI that was defined by the regression equation SI = 105.9 - 6.62E-3 x Age2. SI was significantly correlated with age (r = -0.41, P < 0.001) and with serum NTx concentrations (r = -0.26, P < 0.001), but not with serum levels of bone-specific alkaline phosphatase (BSAP). Years since menopause was also significantly correlated with SI (r = 0.40, P < 0.001). A significant increase in serum NTx concentration occurred at least a decade before a significant decline in SI was evident. In the total study group, 24% of the women had T-scores indicative of osteopenia and 9% had T-scores indicative of osteoporosis, based on US reference data. Although the reported current incidence of fracture is low in women in sub-Saharan West Africa, these data show that after menopause Nigerian women have a decline in bone quality and increase in bone turnover similar to North American Caucasian women.
Milk was collected from 36 Nepalese women, 15 to 32 years of age, in order to investigate relationships between the proportions of intermediate chain-length (C10-C14) fatty acids and critical n-3 and n-6 polyunsaturated fatty acids in the milk lipids they were producing. Serum was also obtained from these lactating women and the fatty acid composition of their serum phospholipid fraction was determined and compared with that of the corresponding milk lipid fraction. Compared to women in technologically advanced parts of the world, the serum phospholipids of the Nepalese women contained nutritionally adequate proportions of linoleic acid (LA) (16.8%), alpha-linolenic acid (ALA) (0.53%), arachidonic acid (AA) (5.69%), and docosahexaenoic acid (DHA) (1.42%). However, although the milk lipids contained adequate proportions of ALA (1.81%), AA (0.43%), and DHA (0.23%), the lipids contained low to moderate percentages of LA (mean, 9.05%). Positive correlations were observed between the proportions of AA (P=0.001, r=0.50) and ALA (P=0.03, r=0.36) in the serum phospholipids and milk lipids of the women. As the proportion of C10-Cl4 fatty acids in the milk lipids increased from 10% to 40%, there was preferential retention of three critical n-3 and n-6 fatty acids (ALA, AA, and DHA) at the expense of two relatively abundant nonessential fatty acids, namely stearic acid and oleic acid. In addition, using fatty acid melting point data and the mol fraction of the 9 most abundant fatty acids in the milk, we estimated the mean melting point (MMP) of the milk lipids of the Nepalese women. The MMPs ranged from 29.3 to 40.5 degrees C (median, 35.5 degrees C). These results indicate that: 1) the levels of AA and ALA in the blood of lactating mothers influence the levels of these fatty acids in the milk they produce; 2) when the mammary gland produces a milk that is rich in C10-Cl4 fatty acids, it somehow regulates triglyceride synthesis in such a way as to ensure that the milk will provide the exclusively breast-fed infant with the amounts of the critical n-3 and n-6 fatty acids it requires for normal growth and development; and 3) the melting point of the milk lipid fraction is determined mainly by the mol % of the intermediate chain-length (C10-C14) fatty acids, oleic acid, linoleic acid, and alpha-linolenic acid.
BACKGROUND: The Fulani of northern Nigeria are seminomadic pastoralists who consume a diet rich in saturated fats, do not use tobacco, are lean, and have an active lifestyle. Little is known about their serum lipid profiles and corresponding risk of cardiovascular disease. OBJECTIVE: We measured serum lipid, homocysteine, folate, and vitamin B-12 concentrations in Fulani men and women and assessed the nutrient content of their diet. DESIGN: Blood samples from 42 men (18-64 y old) and 79 women (15-77 y old) living in the Jos Plateau of Nigeria were analyzed for cholesterol (total, HDL, and LDL), triacylglycerol, homocysteine, folate, and vitamin B-12 serum concentrations. Body composition was determined by bioelectrical impedance analysis. Dietary information was obtained with use of a 7-d dietary recall and a food-frequency questionnaire. Results were compared with US referent ranges. RESULTS: The mean energy content of the Fulani diet was relatively low (men, 6980 kJ; women, 6213 kJ) and the mean protein content was high (men, 20% of energy; women, 16% of energy). Nearly one-half of energy was provided by fat, and one-half of that was derived from saturated fatty acids. The diet provided marginal to adequate amounts of vitamins B-12, B-6, and C but only one-third of the US recommended dietary allowance for folate. The mean total cholesterol, HDL-cholesterol, and triacylglycerol concentrations of Fulani adults were within the referent ranges; the mean LDL-cholesterol concentration of Fulani adults below the range; and the mean serum homocysteine concentration of Fulani men above the range. Homocysteine and folate concentrations were inversely correlated for both men and women. CONCLUSIONS: Despite a diet high in saturated fat, Fulani adults have a lipid profile indicative of a low risk of cardiovascular disease. This finding is likely due to their high activity level and their low total energy intake.
Children with calcium-deficiency rickets experience increased urinary excretion of both essential and non-essential amino acids compared to non-rachitic children of the same age. Chronic wastage of amino acids into the urine could lead to a deficit in fat-free mass (FFM) in rachitic children. We therefore determined the FFM of children with calcium-deficiency rickets in northern Nigeria using bioelectrical impedance analysis. Because of the leg deformities present in the rachitic subjects, we calculated a 'corrected' height for each rachitic subject using the relationship between arm length and height in non-rachitic subjects over the same age range (r = 0.94). A total of 28 children (4 male and 24 female), 2-9 years of age with calcium-deficiency rickets and an equal number of age- and gender-matched controls were recruited into the study. Resistance and reactance measurements were obtained for all subjects and the total body water was calculated using age-specific equations. FFM was then calculated using age- and gender-specific hydration constants. No significant differences were found in the weights or FFM between the rachitic subjects and the controls (8.41 kg +/- 2.19 vs. 8.85 kg +/- 1.90, respectively). We conclude that chronic urinary wastage of amino acids by rachitic children does not result in a deficit in FFM.
Human milk provides newborns with several physiologically important proteins not found in cow's milk, including bile salt-stimulated lipase (BSSL) that compensates for the reduced lipolytic capability of the newborn intestine. We analyzed the milk of two ethnically distinct groups of women in northern Nigeria and Nepal. The milk of the Nepalese women (n = 36) contained slightly more BSSL activity (mean, 38.8 units/mL) than that of Fulani (n = 48; mean, 30.3 units/mL) and Kanuri (n = 90; mean 27.6 units/mL) women in Nigeria. There was also a weak positive correlation between the BSSL content of the milk and the body mass index (BMI) of the lactating women. The BSSL activity declined with the length of lactation for both well-nourished and undernourished women. The presence of a heat-stable inhibitor of BSSL in cow's milk was also demonstrated. This finding, along with the decrease in BSSL activity postgestation, could be of significance to populations such as the Fulani of the western Sahel who supplement the diets of their infants with unpasteurized cow's milk.
Explore the source record for details and available documents.
Levels of lead were determined in the milk of 34 Fulani women in Plateau State in northern Nigeria. The Fulani are nomadic, semi-pastoralists who inhabit the western Sahel, including the countries of Mali, Burkino Faso, the Republic of Niger, Nigeria and Chad. The mean age of the women in this study was 26.0 +/- 7.5 years and their mean body mass index (BMI, kg/m2) was 19.4 (range, 14.5-24.0). Their average parity was 4 (range, 1-10). Milk was collected 2-24 weeks postgestation (mean, 11 weeks). Fifteen of the 34 milk specimens contained measurable lead (limit of detection, 4.6 microg/dL); the milk of the other 19 women (56%) did not contain a detectable level of lead. The data were not normally distributed. The median lead concentration of all 34 milk specimens, determined by end on plasma-axial view spectrometry, was 6.7 microg/dL (range, < 4.6-130 microg/dL). Given the mean weight of the 34 infants in the study (4.6 kg) and assuming that each infant consumed 0.7 L/day of milk, the average lead intake of these exclusively breastfed infants was 9.9 microg/kg/day, a value which is twice the daily permissible intake (DPI) of 5.0 microg/g/day set by the World Health Organization in 1972. These data indicate that some exclusively breastfed Fulani infants in the Jos Plateau are at risk of injury from lead derived from their mothers' milk, and raise questions about the actual blood levels in these nursing infants and the source(s) of the maternal lead.
BACKGROUND: Little is known about the changes that occur in antioxidant levels in response to surgical trauma. The antioxidant system may influence recovery and healing after operation. Miller et al described a reliable assay for total antioxidant capacity of serum. We studied changes in antioxidant levels secondary to operation using this assay. METHODS: Twenty-seven patients were studied: 14 abdominal and 13 breast cancer operations. Initial blood samples were obtained when starting the preoperative intravenous line, the second in the recovery room, and every 6 hours thereafter. RESULTS: Levels did not correlate with diagnosis, extent of operation, age, body mass index, or complications. Differences between preoperative and postoperative values in the down and up groups were significant at P = 0.002 and P = 0.023, respectively. Differences in initial levels between the down and up groups were significant at P = 0.005. Levels 12 hours after operation were stable. CONCLUSIONS: Rapid return to a baseline of approximately 1 micromole/L, regardless of the direction of initial response, supports the concept of a set point for regulation of serum's antioxidant capacity.
We previously reported that, relative to milk of women elsewhere in the world, the lipid fraction of milk of Fulani women in northern Nigeria contained relatively low proportions of alpha-linolenic acid and docosahexaenoic acid (DHA). This led us to question the essential fatty acid status of Fulani infants and the relation between the proportion of critical n-3 and n-6 fatty acids in the serum phospholipids of the mothers, their milk, and the serum phospholipids of their exclusively breast-fed infants. We were also interested in the effect de novo intermediate chain length-fatty acids (C10-C14) had on the proportions of critical and non-essential fatty acids in milk. Capillary gas-liquid chromatography was used to analyze the fatty acid content of the total milk lipids of 34 Fulani women, as well as the fatty acid content of serum phospholipids of the women and their breast-fed infants during the first 6 months of life. The proportions of critical n-3 and n-6 fatty acids in the milk of the Fulani women were adequate, but the proportions of these same fatty acids were low in their exclusively breast-fed infants. The serum phospholipids of the infants contained 18.8% linoleic acid, 0.13% alpha-linolenic acid, 12.8% arachidonic acid, and 3.40% DHA, whereas, the mean percentages of linoleic, alpha-linolenic, arachidonic and DHA in the serum phospholipids of the Fulani mothers' were 21.4, 0.20, 9.79, and 1.97, respectively. There was a strong positive correlation between fatty acid content of serum phospholipids of Fulani women and the fatty acid content of their milk lipids. As the proportion of C10-C14 fatty acids in the milk lipids increased, the proportions of critical n-3 and n-6 fatty acids in milk remained relatively constant; however, proportions of three non-essential fatty acids decreased dramatically. C10-C14 fatty acids do not appear to displace critical n-3 and n-6 fatty acids in milk.
Serum levels of aminoterminal extension propeptides (PINP), the carboxyterminal telopeptide (ICTP), and the cross-linked N-telopeptides (NTx) of type I collagen were determined in 78 healthy, elderly men aged 76 +/- 5 years in 1993 and 1996 and compared with bone mineral density (BMD) measurements of their lumbar spine, femoral neck, and total body regions made using dual X-ray absorptiometry. Compared with 11 men who had normal lumbar spine (SBMD) and femoral neck BMD (NBMD), 13 of the subjects with SBMD and NBMD classified as osteopenic by t-score criterion had higher mean serum levels of PINP and alkaline phosphatase activity, but these increases were not statistically significant at the 95% confidence interval. In osteopenic men, a correlation between SBMD and NTx was detected (r = -0.66, p = 0.01). Within the entire population, the serum NTx level correlated with NBMD (r = -0.26, p < 0.05) and PINP (r = +0.63, p < 0.0001), and the change in the circulating concentration of PINP over the 3 year interval correlated with the magnitude of change in total body BMD (r = -0.28, p = 0.02), NBMD (r = -0.24, p = 0.05), and SBMD (r = -0.36, p = 0. 03) as well as with the change in serum NTx levels (r = 0.43, p < 0. 001). The change in the circulating ICTP level was also related to the change in NBMD (r = -0.24, p = 0.01). Together, weight and the serum PINP level accounted for 25% of total body BMD variance in elderly men. These results indicate that larger populations of men and women should be screened over longer time intervals to explore the value of serial measurement of serum collagen metabolites in predicting bone loss in the spine and hip.
In the western Sahel and many other regions of sub-Saharan Africa, wild edible plants contribute significantly to human diets, not only during periods when cereal staples are scarce, but also when they are readily available. Although there have been published reports regarding the nutrient contents of these plant foods, little attention has been devoted to their content of antinutrients such as calcium chelators and inhibitors of the pancreas-derived proteases, trypsin and chymotrypsin, which are required for the efficient digestion and absorption of dietary proteins. In this study, aqueous extracts of 61 different leaves, seeds, fruits and flowers of edible plants gathered in the Republic of Niger were analyzed for their content of trypsin inhibitory substances using alpha-N-benzoyl-DL-arginine-p-nitroanilide as the substrate and bovine trypsin as the enzyme source. Twelve of these plant foods contained more antitrypsin activity than soybeans (1.34-8.18 vs. 1.32 microg trypsin inhibited/mg dry weight). Boiling for 3 min did not inactivate the antitrypsin activity in most of the plant extracts. These data confirm that more than half of the wild edible plant foods widely consumed by various populations who inhabit the western Sahel contain significant quantities of heat-stable trypsin inhibitor that could possibly compromise the bioavailability of proteins present in the diets of these populations.
The milk of 89 women in northern Nigeria was analyzed for the fatty acid composition of the total milk lipids, and assessed for the effect nutritional status has on the conservation of essential and non-essential fatty acids when the proportions of C(10)-C(14)fatty acids are increased. The women were stratified on the basis of their body mass index, and calculations were made to estimate the effects of a 3.3-fold increase in the proportion of C(10)-C(14)fatty acids on the proportion of alpha-linolenic acid, docosahexaenoic acid, linoleic acid and arachidonic in total milk lipids. In the well-nourished group (group III, body mass index >23 kg/m(2)), the critical n-3 and n-6 fatty acids were not conserved, while in poorly nourished women (group I, body mass index <19 kg/m(2)), marked conservation of alpha-linolenic acid, docosahexaenoic acid, arachidonic acid, and palmitic acid was seen. Poor nutritional status of the mother appears to promote selective retention of critical essential and non-essential fatty acids in the milk lipid fraction.
Intermediate chain-length fatty acids (C10-C14) in human milk triglycerides provide an easily absorbable fuel that provide a significant amount of the energy needed for growth during the first few months of life. The C10-C14 fatty acid and trace mineral content of human milk is variable. In this report we examined the relationship between the content of calcium, copper, magnesium, manganese, phosphorus, and zinc, and the weight percentage of C10-C14 fatty acids in milk from 33 Fulani women in northern Nigeria between 2 and 24 weeks post-gestation. The milk from these women contained proportions of C10-C14 fatty acids that were comparable to those reported for other populations around the world, as were the concentrations of Ca, Cu, Mg, Mn, Zn and P. Significant correlations were observed between the milk content of Cu and the wt% of C10 (P=0. 005, r=0.475), C12 (P=0.001, r=0.539), C14 (P=0.44, r=0.352) and the total intermediate chain-length fatty acids (P=0.008, r=0.450). No correlations were observed between these fatty acids and any of the other five minerals. We speculate that the relationship between Cu and fatty acids could be related to a requirement for Cu by an enzyme required for C10-C14 fatty acid biosynthesis (e.g. decanoyl deacylase) in mammary tissue, or to some unique Cu binding properties of the intermediate chain length fatty acids.
Explore the source record for details and available documents.
We used bioelectrical impedance (BIA) to investigate the body composition of children with sickle cell disease (SCD) in northern Nigeria. A total of 48 children with SCD and 51 controls between 3 and 20 years of age were studied. A significant difference was found in the weights of male subjects over the age of 10 years compared to controls (p = 0.01), but not in height. Significant differences were also observed for SCD males in the 10-18-year-old age range in body mass index (p = 0.001), fat free mass (p = 0.001), per cent fat free mass, (p = 0.02), body fat (p = 0.02), and per cent body fat (p = 0.02). No significant differences in any of these parameters between SCD subjects and controls were obtained for males under the age of 10 years. There were no significant differences in the height, weight, body mass index, or fat free mass for female SCD subjects compared to controls over the age range we studied. However, there were significant differences in the per cent fat free mass (p = 0.006), body fat (p = 0.025), and per cent body fat (p = 0.01) for female SCD subjects over the age of 10 years compared to controls. In addition to documenting differences in the body composition of adolescent boys with sickle cell disease in Nigeria, this study also demonstrated the feasibility of using bioelectrical impedance to analyse the body composition of individuals under the hot, arid conditions which prevail in sub-Saharan Africa.
Breastmilk from 15 healthy lactating women (21-31 years of age) from the hot, semi-arid sahel of Africa were analysed for copper, iron, zinc, magnesium, manganese, sodium, potassium, and phosphorus. Relative to published data from other populations worldwide, the milk of the Jos women appeared to contain adequate levels of magnesium, manganese, sodium, potassium, phosphorus and iron, but relatively low concentrations of zinc (1.07 micrograms/ml) and copper (170 micrograms/l). The sera of the exclusively breastfed infants nursed by these mothers contained levels of all these minerals that are within the international reference range of values. No statistically significant correlation was observed between the level of a particular mineral in the mothers' milk and the sera of their nursing infants.