Determination of boron content in foods and assessment of dietary boron intake of habitants in Guangzhou city

Objective To detect boron concentrations in foods and to estimate dietary boron intake in residents of Guangzhou city.Methods Totally 687 samples of 113 kinds of food available from markets in Guangzhou city were collected from 2010 to 2012 and the concentration of boron in the samples was detected with curcumin spectrophotometric method.The dietary boron intakes in habitants of Guangzhou city were also estimated combined with the data from the survey on status of nutrition in the residents.Results The concentration of boron varies in different foodstuffs,and bean(18.6±10.27 mg/kg),nut(10.95±7.49 mg/kg),fruits(1.34±7.26 mg/kg),vegetables(1.24±0.91 mg/kg) are more rich in boron than cereal and animal foods.The boron content of most products was similar to their raw materials,but two meat ball samples was up to 58.12 and 66.92 mg/kg and one rice dumpling was only 2.65 mg/kg.The average daily dietary boron intake for Chinese and Guangzhou habitants was 1.32 mg and 1.71 mg.The main sources of boron are vegetables and its products(25.76% and 21.64%),meat and its products(22.73% and 33.33%),rice and its products(12.12% and 13.45%),and bean and its products(8.33% and 12.92%).Conclusion The rank of boron concentration in foods from high to low is bean,nuts,fruits,vegetables,animal foods,and cereal.Some of the foods may be added with borax or boric acid unlawfully.The average daily intake of boron from dietary consumption for habitants is within the safe range recommed by World Health Organization,but it will increase hazard to health if people eat too much food with illegal boron additive.