Bimodal distribution of fasting gastric acidity in a rural African population.

SETTING: The people of Transkei eat a diet high in linoleic acid, the principal fatty acid in maize. The theory has been put forward that a diet high in linoleic acid and low in fat and riboflavin, such as the traditional diet in Transkei, results in overproduction of prostaglandin E2 in the gastric mucosa, and that this overproduction in turn causes a suppression of gastric acid production. OBJECTIVE: To investigate the effect of diet on fasting gastric pH in a rural black African population. DESIGN: Fasting gastric acid samples were obtained by fine nasogastric tube aspiration from 150 volunteers at a rural health clinic. The pH of these samples was measured and a full dietary questionnaire was used. Helicobacter pylori serology was done on a subgroup of 30 volunteers. RESULTS AND CONCLUSIONS: A bimodal pH distribution was found. Approximately half the population had a gastric pH within the range 1-4. Half had a pH of over 4. A high pH was significantly associated with consumption of maize (p = 0.006), and with consumption of both pumpkin and beans (p = 0.006). A high proportion of this rural African population has a diet-associated abnormally high gastric pH. The pattern of upper gastrointestinal disease may be significantly affected by diet in this community and in others with a similar diet.

Serum leptin concentration in a rural African population.

OBJECTIVE: To determine the serum leptin concentration in a cohort of healthy rural Africans, it's relation to the commonly used anthropometric measures of obesity and its relation to the patterns of distribution of fat in the body. DESIGN: A cross-sectional population survey. SETTING: Baziya area, Transkei region, South Africa. SUBJECTS: One hundred and thirty five (79 females and 56 males) healthy adults from the Baziya location, Transkei aged 17-70 years were selected by stratified random sampling. MEASUREMENTS: Anthropometric measurements of height, weight, and skinfold thickness at the biceps, triceps, subscapular and suprailiac sites and derived total body fat and ratios of fat distribution. Fasting serum leptin using the sandwich ELISA method. RESULTS: Skinfold measurement was significantly higher in the females than the males throughout the age range. Centralization of body fat to the trunk was significantly greater in the males than in the females. Serum leptin concentration was higher in the females (mean = 13.5 ng/ml; 95% confidence interval = 10.0-16.8) than in the males (mean = 5.2 ng/ml; 95% confidence interval = 2.8-7.6) (p < 0.001). The gender difference in leptin concentration persists when expressed as serum leptin per kilogram of fat mass (serum leptin (ng/ml)/FM). The mean value for the males was 5.1 ng/ml/kg (95% confidence interval = 2.9-7.3) compared to the mean value for females of 6.9 ng/ml/kg (95% confidence interval = 5.4-8.3) (p < 0.05). In the females BMI and body fat were significant contributors to the variance in serum leptin. In the males the upper-to-lower trunk skinfold thickness ratio and BMI were the significant contributors to the variance in serum leptin concentration. Deposition of fat in the abdomen did not have a significant contribution to the variance in circulating leptin in both sexes. CONCLUSION: Serum leptin concentration in rural Africans is similar to that observed in other communities with the exception that regional fat distribution has a significant influence on the leptin levels in the males.