This study measured manganese in betel quids, their components and some Bangladeshi foods sold in the United Kingdom, and in urine from UK-resident Bangladeshi adults who did or did not chew betel quid. Chewers had about three times the urinary manganese of non-chewers. Combining measured and literature values, the authors modelled a total daily manganese intake for people in Bangladesh that is far above intakes reported for other countries.
Key numbers
- Urinary manganese, specific-gravity adjusted: chewers mean 1.93 µg/L (SD 1.8, n = 15) versus non-chewers 0.62 µg/L (SD 0.4, n = 22), p = 0.009; all 37 samples mean 1.04 µg/L, median 0.45 µg/L, range 0.08 to 5.2 µg/L (Results, p. 4).
- Manganese in quid components (dry material, duplicate measurements; Table 1, p. 5): ordinary betel quid mean 41 mg/kg (SD 27, n = 26); sweetened quid 19 mg/kg (SD 10, n = 12); Piper betel leaves 136 mg/kg (SD 106, n = 30; maximum 518 mg/kg); areca nut 12 mg/kg (n = 7); lime 40 mg/kg (n = 6); tobacco leaves 367 mg/kg (n = 2); flavored tobacco (zarda) 102 mg/kg (n = 13).
- Provisional maximum tolerable daily intake used by the authors: 140 µg/kg body weight/day, or 9520 µg/day for a 68 kg adult; six ordinary quids give 18% of that value (Table 3, p. 5).
- Modelled intake for people in Bangladesh: 18.7 mg/day without quids (foods 16.564 mg plus water 2.160 mg) and 20.3 mg/day with six quids; modelled intake for UK Bangladeshis 8.64 mg/day for non-chewers and 9.88 mg/day for chewers (Tables 2 and 4, pp. 5 and 7).
- Largest modelled food contributions in Bangladesh: steamed rice 5465 µg/day, tea infusions 4168 µg/day, green vegetables 2751 µg/day, lentils and beans 1285 µg/day (Table 2, p. 5).
- Target hazard quotients reported: 0.18 for six quids, 0.21 for water, 1.55 for all foods, 1.94 for the full diet with water and quids (Results, p. 6).
- The paper cites a World Health Organization value of 0.400 mg/L for manganese in groundwater as background (Background, p. 1).
Methods (brief)
Urine from 37 volunteers was digested with nitric acid and hydrogen peroxide. Betel leaves (washed), areca nut, lime, tobacco, zarda, quids and rice were dried, ground, microwave digested and analyzed by ICP-MS. Recoveries were 92% and 94% for rice flour and tomato leaf reference materials and 105% for a urine reference material. Intake modelling used literature food consumption, water intake of 2.7 L/day, three cups of tea per day and a 68 kg body weight.
Evidence fitness
The concentrations in quid components and the urine contrast are measured data. The total daily intakes and hazard quotients are modelled from mixed measured and literature inputs and should be treated as estimates. Urine values come from a small UK convenience sample and do not represent residents of Bangladesh.
Limitations
Only 37 urine samples were available, and chewer and non-chewer groups differ in sex ratio. Products were bought in UK shops, mostly of Bangladeshi origin. Drinking water values for Bangladesh are taken from earlier literature, and the authors note that bioavailability of manganese from quids, food and water may differ.
Related evidence
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