A comparison between the effects of black tea and rooibos on the iron status of primary school children / Petronella Breet
Background: Clinical studies have shown that tea consumption leads to decreased iron absorption. This finding is however, not supported by epidemiological studies, where no relationship between an increased tea consumption and a lower iron status in a population at risk of iron depletion has been found. Objectives: The main aim of this study was to compare the effects of black tea and Rooibos consumption on the iron status of primary school children in a rural setting in Potchefstroom, South Africa. Methods: One hundred and seventy five children, aged six to fifteen years, participated in this single blind, randomised, parallel intervention trial. Subjects were randomly allocated to receive two 200ml servings of either black tea or Rooibos with milk and sugar. These beverages were consumed during breaks and at the same time as the food h m the school-feeding scheme. The trial proceeded for sixteen weeks. The children received antihelminthic treatment (500mg mebendazole) at baseline. Haemoglobii haematocrit, serum iron, ferritin and transferfin were measured and total iron binding capacity and transferrin saturation were calculated. Trained fieldworkers measured dietary intakes by means of 24-hour dietary recalls and anthropometrists took anthropometric measurements. All the above mentioned data were gathered at the beginning and at the end of the intervention period. Results: Measurements indicated a study population that is malnourished in terms of anthropometrical indices and nutrient intakes. Biochemical markers of iron status also indicated that the population could be at risk of iron depletion. Changes in red blood cell count, haemoglobin, haematocrit, mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV), serum iron, transferrin, transferrin saturation, ferritin and total iron binding capacity (TIBC) did not differ significantly between the two groups. Mean red blood cell count, haematocrit, MCV, transferrin and TIBC increased significantly h m baseline to end in both groups (all p<0.0001) and MCH decreased significantly (p<.0001). Mean haemoglobin increased significantly with black tea consumption (p=0.002), although not with the consumption of Rooibos (p=0.073). Conclusion: Black tea or Rooibos consumption has similar effects on the iron status of primary school children. Iron status was not compromised by black tea in comparison with Rooibos. This questions the proposed limitation of black tea consumption as a public health strategy in order to combat iron deficiency in a population with marginal iron status.
- ETD@PUK