The effect of short-term deprivatioa (10 days) on plasma cholesterol, triglyceride, phospholipids, free fatty acids, high density lipoprotein cholesterol (HDLC) and low density lipoprotein cholesterol (LDLC) were investigated in seven medical students (Urban adults) aged between 21 and 24 years and eight Village Adults aged between 30 and 40 years. There were significant falls in all the plasma lipids except free fatty acids and the plasma triglycerides of the village adults. Plasma proteins in all subjects were reduced while the fall in albumin was significant only for the urban adults. Positive correlation of Mbody fat with plasma lipids was only significant for HDLC in the urban adults and triglycerides for the village adults. There was no correlation between plasma proteins and lipids except with HDLC for village adults. Tbe village adults however, were observed to show a less stressful effect on plasma lipids than the Urban adults though they reacted to the short-term deprivation more or less in the same manner.
The fall in plasma lipids have been attributed to a fall in the lipo-protein fractions which arc the chief carriers of cholesterol, triglycerides and phospholipids while freefatty acids were- not affected within the short period of the experiment;
1. The present study was carried out to estimate precisely, via the nitrogen balance technique,
requirement or Nigerians (earlier estimated via the obligatory N method) using graded levels
2. Fifteen medical students of the University of Ibadan who volunteered to participate in the study
Graded levels of protein (0-3, 0-45, 0-6 and 0-75 g/kg body-weight per d) derived from foods similar to be consumed by the subjects.
3. Each subject was given each of the dietary protein levels for a period of 10 d. Subjects were divided
groups and the feeding pattern followed a criss-cross design with one group starting with the highest level of
intake (0-75 g) and the second group starting with the lowest level of protein intake (0 3 g). N
intake during each of the eleven experimental periods was maintained at 0-2 MJ/kg per d. After
adaptation period in each experimental period, 24 h urine and faecal samples were collected in marked
for five consecutive days for N determination.
4. Mean N balance during consumption of the four protein levels (0-30, 0-43, 0-6 and 0-75 g/kg) t
(SD 8.07), — 9.90 (SD 6.64), +9.70 (SD 4.15) and +5.13 (SD 4.62) respectively. Using regression analyses
daily N requirement was estimated at 110.25 mg N/kg body-weight (0.69 g protein/kg body-weight).
allowances for individual variations to cover 97.5 % or the population adjusted this value to 0-75g
body-weight. Net protein utilization for the diet at maintenance level was estimated at 57.5.
1. A continuous 40 d metabolic nitrogen balance study was conducted on twelve young men age years to evaluate the adequacy of a previously determined safe level of protein intake.
2. Subjects were fed on diets which they were habitually accustomed to and which provided a pro 0.75 g protein (N x 6.25)/kg body-weight per d as the safe level and an energy intake level of 0.2 f weight per d. N balances, including an estimate for integumental losses as well as certain biochemical were determined for the last 5 d of two consecutive 20 d diet periods.
3. Only two of the twelve subjects were observed to be in negative N balance during the final 5 < period. N balance was generally positive at 8-24 (SD 8.61) mg N/kg body-weight, thus confirming of 0.75 g protein/kg body-weight per d as a safe level of protein intake in the majority of the subject
Twelve healthy female subjects aged < between 21 and 32 years were fed graded levels of protein inform of the habitual diet to which they were accustomed, in order to differentiate effects of this dietary component on urinary and plasma uric acid excretion. Urinary uric acid increased significantly with increase in the level of protein intake. The average daily uric-acid excretion at the four levels of protein tested were 297.7 ± 44.5, 282.9 ± 45.0. 304.6 ± 31.8 and 331.4 ±26.5 mg/day for 15.7. 21.4, 27.4 and 32.7g protein/day respectively. Thus urinary uric acid increased linearly by 2.14 mg/g protein. There is, therefore, a positive correlation between the amount of protein Vitamin and urinary uric acid excretion (r - '0.34) However, plasma uric acid did not change with Increase In dietary protein. This was attributed to a possible increase in renal clearance.
The effect of varying energy intakes on nitrogen balance was investigated in thirteen young women aged between 21 and 32 years. The subjects were fed a previously determined minimum requirement of protein (0.47 g/kg) at two levels of dietary energy, high energy intake at 48.4±3.70 kcal/kg bodyweight and low energy intake of 33.8±2.86 kcal/kg bodyweight (about 20% above and below the estimated energy requirement based on their energy expenditure); Nitrogen balance was determined from the nitrogen in food, urine, feces and sweat. Nitrogen balance was -8.6±5.44 mgN/kg with the low energy intake and increased to +10.82±6.35 mgN/kg with the high energy intake. Regression analysis, showed that all subjects maintained zero nitrogen balance with an average energy intake of 40±0.94 kcal/kg/day. Variation in energy intake also altered the net protein utilization of the habitual diet in till subjects by 1.0 to 3.5 units/kcal per kg body weight. Energy requirement was estimated on lite basis of constant body weight and the nitrogen balance. Body weight was maintained constant at an energy intake of 40.8±4.21 kcal/kg body weight
Thirteen normal healthy female adults aged 21 to 32 years participated in an energy balance study while they consumed their habitual diet at two energy levels (33.8±2.96 and 48.4±3.7 kcal/kg/day) and a protein level of 0.47g protein/kg/day. The physical activity of the subjects was closely monitored and kept fairly constant. Energy balance calculated from the gross energy intake, energy excreted (urine, feces and sweat) and expenditure on activity was affected considerably by the level of the gross energy intake. Energy balances were -6.3512.57 and +7.31±2.24 kcal/kg/day for the low and high energy intakes respectively. Energy balance improved by a factor of 0.9410.1 for every kcal/kg rise in gross energy intake. Mean energy requirement to achieve energy balance in all the subjects was estimated at 40.311.4 kcal/kg body weight.
Nitrogen balance studies were carried out in two separate experiments involving a total of fifteen acclimatized young women. The aim was to determine the effects of different levels of protein intake on sweat nitrogen iosBes. The looses were determined through the collection of 24 hour total body sweat samples under control led environmental conditions. In nine of the subjects fed on graded level of protein for a ten-day period at a time, sweat nitrogen loosen varied with nitrogen intake, being 5.45+0.79, 6.36+0.70, 6.65+0.73 and 7.1O+0.B7mg N/kg/day at protein intakes of 0.3, 0.4, 0.5 and 0.6 protein/kg/day, respectively. Obligatory nitrogen loss in sweat extrapolated from linear, regression analysis of nitrogen intake versus sweat nitrogen loss was 4.20 mg N/kg/day. When the subjects were fed a single level of protein (0.6 g/kg/day) for forty days, the mean Bweat nitrogen loss of the women was 9.45+0.44 mg/kg/day. Thus the recommended allowance for sweat nitrogen losses (3-4 mg N/kg/day) in estimating protein requirement by the 1985 FAO/WHO/UNU expert report is an underestimation under conditions prevailing in tropical countries.
Haemoglobin (Hb), haematocrit (Hcl), plasma iron (PI) and total iron binding capacity (TIBC) were measured in 100 adolescents (68 boys and 32 girls) aged 14-17 years in three secondary schools on Ojo Local Government Area of Lagos State. Of the subjects, 33, 26 and 31 per cent had Hb, Kct and PI Levels below accepted normal values respectively. 26 per cent of them had values below normal in all the three parameter .
Further analysis of Hb levels in the population studied showed that 44.74 per cent of the females and 25.8 percent of the males had Hb levels below normal (11 g/dl) indicating a higher occurence of anaemia in the females. Direct measurements of 7-day food intake revealed that intakes of iron, protein and energy were below recommended allowance for both sexes. A significant relationship was also observed between dietary iron intake and scrum iron levels.
The level of lead in the blood of occupationally exposed workers among 23 automechanics and 14 petrol attendants from five different sites in Lagos and 20 nonexposed students of the Lagos State University, Lagos, serving as control, was determined. The mean bleed lead values in the automechanics and petrol attendants, 67.6 ±13.2µg/dl and 70.6 + 19.0µg/dl respectively, were significantly higher than the value of 25.6 ± 6.7µg/dl among students (P < 0.05). Linear regression analysis showed that among the automechanics, years of experience at the job had an inverse relationship with blood lead. Blood lead decreased by a factor of 0.45 for every year on the job. The situation was different with petrol attendants. Among the latter group, there was a positive correlation between the years of experience on the job and blood lead values. An increase of 2.2 µg/dl of blood lead was observed for every year on the job. Age was poorly correlated with blood lead values among all subjects. Blood lead value was significantly higher among smokers in all the three groups studied (P < 0.05).
A short-term N balance study was conducted In twelve healthy female adults aged 21-32 years to determine their protein requirement. Four dietary protein levels (0 3, 0-4, 0-5 and 0 6 g protein/kg per d) were used. Energy intake of the subjects were kept constant at 018 MJ/kgper d. All subjects maintained their normal activity throughout the study period. N excretion was determined from the measurements of N in a total collection of urine, faeces, sweat and menstrual fluid for each dietary period. N balance during the four protein levels were — 1515 (sd 5-95), -5-53 (sd 6-71), +615 (sd 4.76) and +12 05 (sd 8.63) mg N/kg per d for 0 3, 0 4, 0-5 and 0-6 g protein/kg per d respectively. The calculated average N requirements from regression analysis was 76 0 (sd 3 37) mg N/kg per d (0 48 g protein/kg per d). The estimate of allowance for individual variation to cover the 97 5% population was 95 mg N/kg per day(0-6 g protein/kg per d). The net protein utilization (NPU) of the diet was 0-55. When compared with a similar study with men, there was a significant difference in the protein requirement between sexes. Thus, the unjustifiable sex difference in the protein allowance recommended by the Food and Agriculture Organization/World Health Organization/United Nations University (1985) Expert Consultation group must be reviewed.