Dietary intake of phytate, zinc and calcium of self-selected diets of Ubon Ratchathani and Bangkok subjects, Thailand

Abstract

The dietaty intakes of phytate, zinc and calcium of volunteers in Ubon Ratchathani (northeast Thailand) and Bangkok metropolitan were studied. The selected subjects were 10 men and 10 women from each area. The daily diets were collected for 5 consecutive days using duplicate portion technique. The diets were blended, aliquoted, mixed, freeze-dried and homogenized. Phytate was analysed by using ion exchange coupled with colorimetric method. Zinc and calcium were analysed by atomic absorption spectrophotometer. The total intakes of phytate were 1104.8 ± 965.2 and 1139.3 ± 481.1 mg/day for males and females in Ubon Ratchathani, 1304.7 ± 956.2 and 997.1 ± 435.1 mg/day for males and females in Bangkok. The zinc intakes were 20.0 ± 8.8, 12.7 ± 4.6, 7.7 ± 1.8 and 6.1 ± 1.2 mg/day for males and females in Ubon Ratchathani and for males and females in Bongkok, respectively. The calcium intakes were 524.6 ± 259.9, 379.9 ± 111.4 for males and females in Ubon Ratchathani and 366.5 ± 150.5, 286.7 ± 68.7 mg/day for males and females in Bangkok. The calculated phytate/zinc molar ratios were 7.5, 3.9 for males and females in Ubon Ratchathani and 16.2 and 17.5 for males and females in Bangkok This study indicated that subjects from Bangkok have a phytate/zinc ratio higher than those in Ubon Ratchathani and higher than 12. This may effect the availability of some micronutrients such as zinc, calcium and iron. The daily intakes of zinc and calcuim in these two groups were low compared to Thai RDA.