New way of cooking rice removes arsenic and retains mineral nutrients, study shows
Cooking rice in a certain way removes over 50 per cent of the naturally occurring arsenic in brown rice, and 74 per cent in white rice, according to new research.
Arsenic, which is
classified as a Group 1 carcinogen by the International Agency for
Research on Cancer, is water-soluble - so it accumulates in rice, which
is grown in flooded fields more than other cereals. Arsenic exposure
affects almost every organ in the body and can cause skin lesions,
cancer, diabetes and lung diseases.
Rice is known to accumulate
around ten times as much arsenic as other cereals. In rice grains
arsenic is concentrated in the outer bran layer surrounding the
endosperm. This means that brown rice, (unmilled or unpolished rice that
retains its bran) contains more arsenic than white rice. This milling
process removes arsenic from white rice but also removes 75-90% of its
Previous research from the University of Sheffield found half
of the rice consumed in the UK exceeded European Commission regulations
for levels of arsenic in rice meant for the consumption for infants or young children (see the News below).
The new study: This new study tested different ways to cook rice to try and reduce the arsenic content and the team from the Institute for Sustainable Food
found that by using a home-friendly way of cooking rice, the
‘parboiling with absorption method’ (PBA), most of the arsenic was
removed, while keeping most nutrients in the cooked rice.
PBA method involves parboiling the rice in pre-boiled water for five
minutes before draining and refreshing the water, then cooking it on a
lower heat to absorb all the water.
"For rice consumers, this is excellent news. There are genuine
concerns amongst the population about eating rice due to arsenic.
Previous studies have shown that cooking rice in excess water could
remove arsenic but the problem is it also removes nutrients.
aim was to optimise the method to remove arsenic while keeping maximum
nutrients in the cooked rice. Our newly developed method, PBA, is easy
and home-friendly so that everyone can use it. We don't know the amount
of arsenic in each packet rice we buy; even though brown rice is
nutritionally superior to white rice as our data shows, it contains more
arsenic than white rice. With our new method we are able to
significantly reduce the arsenic exposure while reducing the loss of key
We highly recommend this method while preparing
rice for infants and children as they are highly vulnerable to arsenic
exposure risks," commented Dr Manoj Menon, Environmental Soil Scientist
in the Department of Geography at the University of Sheffield and lead
author of the study.
Source: This article has been republished from material presented by The University of Sheffield. Note: material may have been edited for length and content.
The original study:
M. Menon, W. Dong, X. Chen, J. Hufton, E.J. Rhodes. Improved rice cooking
approach to maximise arsenic removal while preserving nutrient elements.
Science of The Total Environment. Published online October 29, 2020:143341. DOI: 10.1016/j.scitotenv.2020.143341
O. Atiaga, L.M. Nunes, X.L. Otero, Effect of cooking on arsenic concentration in rice,Environ. Sci. Pollut. Res., 27 (2020) 10757-10765. DOI: 10.1007/s11356-019-07552-2
N.R. Chowdhury, A. Das, M. Joardar, A. De, D. Mridha, R. Das, M.M. Rahman, T. Roychowdhury, Flow
of arsenic between rice grain and water: its interaction, accumulation
and distribution in different fractions of cooked rice,Sci. Total Environ., 731 (2020) 138937. DOI: 10.1016/j.scitotenv.2020.138937
F. Zhang, F. Gu, H. Yan, Z. He, B. Wang, H. Liu, T. Yang, F. Wang, Effects of soaking process on arsenic and other mineral elements in brown rice,Food Sci. Hum. Wellness. (2020), DOI: 10.1016/j.fshw.2020.01.005
W. Liao, G. Wang, K. Li, W. Zhao, Y. Wu, Effect of cooking on speciation and in vitro bioaccessibility of Hg and As from rice, using ordinary and pressure cookers,Biol. Trace Elem. Res. (2019) . DOI: 10.1007/s12011-018-1345-7
U. Mandal, P. Singh, A.K. Kundu, D. Chatterjee, J. Nriagu, S. Bhowmick, Arsenic retention in cooked rice: effects of rice type, cooking water, and indigenous cooking methods in West Bengal, India,Sci. Total Environ., 648 (2019) 720-727. DOI: 10.1016/j.scitotenv.2018.08.172
K. Sharafi, M. Yunesian, A.H. Mahvi, M. Pirsaheb, S. Nazmara, R. Nabizadeh Nodehi, Advantages
and disadvantages of different pre-cooking and cooking methods in
removal of essential and toxic metals from various rice types-human
health risk assessment in Tehran households, Iran,Ecotoxicol. Environ. Saf., 175 (2019) 128-137. DOI: 10.1016/j.ecoenv.2019.03.056
T. Mwale, M.M. Rahman, D. Mondal, Risk and benefit of different cooking methods on essential elements and arsenic in rice,Int. J. Environ. Res. Public Health, 15 (2018) 1-11. DOI: 10.3390/ijerph15061056
Kunlun Liu, Jiabao Zheng, Fusheng Chen, Effects of washing, soaking and domestic cooking on cadmium, arsenic and lead bioaccessibilities in rice, J. Sci. Food Agric., 98 (2018) 3829–3835. DOI: 10.1002/jsfa.8897
Karlien Cheyns, Nadia Waegeneers, Tom Van de Wiele, Ann Ruttens, Arsenic Release from Foodstuffs upon Food Preparation, J. Agric. Food Chem. 2017, 65, 2443−2453. DOI: 10.1021/acs.jafc.6b05721
Petru Jitaru, Sandrine Millour, Marco Roman, Kaoutar El Koulali, Laurent Noël, Thierry Guérin, Exposure assessment of arsenic speciation in different rice types depending on the cooking mode, J. Food Compos. Anal., 54 (2016) 37–47. DOI: 10.1016/j.jfca.2016.09.007
Ping Zhuang, Chaosheng Zhang, Yingwen Li, Bi Zou, Hui Mo, Kejun Wu, Jingtao Wu, Zhian Li, Assessment of influences of cooking on cadmium and arsenic bioaccessibility in rice, using an in vitro physiologically-based extraction test, Food Chemistry 213 (2016) 206–214. DOI: 10.1016/j.foodchem.2016.06.066
M. Carey, X. Jiujin, J.G. Farias, A.A. Meharg, Rethinking rice preparation for highly efficient removal of inorganic arsenic using percolating cooking water,PLoS One, 10 (2015) e0131608. DOI: 10.1371/journal.pone.0131608
P.J. Gray, S.D. Conklin, T.I. Todorov, S.M. Kasko, Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain,Food Addit. Contam. - Part A, 33 (2015) 78-85. DOI: 10.1080/19440049.2015.1103906
S. Naito, E. Matsumoto, K. Shindoh, T. Nishimura, Effects of polishing, cooking, and storing on total arsenic and arsenic species concentrations in rice cultivated in Japan,Food Chem., 168 (2015) 294-301. DOI: 10.1016/J.FOODCHEM.2014.07.060
A.J. Signes-Pastor, S.W. Al-Rmalli, R.O. Jenkins, Á.A. Carbonell-Barrachina, P.I. Haris, Arsenic bioaccessibility in cooked rice as affected by arsenic in cooking water,J. Food Sci., 77 (2012) T201-T206. DOI: 10.1111/j.1750-3841.2012.02948.x
Victor G. Mihucz, Geert Silversmit, Imre Szalóki, Björn de Samber, Tom Schoonjans, Enikö Tatár, László Vincze, István Virág, Jun Yao, Gyula Záray, Removal of some elements from washed and cooked rice studied by inductively coupled plasma mass spectrometry and synchrotron based confocal micro-X-ray fluorescence, Food Chemistry 121 (2010) 290–297. DOI: 10.1016/j.foodchem.2009.11.090
A. Raab, C. Baskaran, J. Feldmann, A.A. Meharg, Cooking rice in a high water to rice ratio reduces inorganic arsenic content,J. Environ. Monit., 11 (2009) 41-44. DOI: 10.1039/b816906c
Silvia Torres-Escribano, Mariana Leal, Dinoraz Vélez, Rosa Montoro, Total and Inorganic Arsenic Concentrations in Rice Sold in Spain, Effect of Cooking, and Risk Assessment, Environ. Sci. Technol., 42/10 (2008) 3867-3872. DOI: 10.1021/es071516m
A. Signes, K. Mitra, F. Burlo, A.A. Carbonell-Barrachina, Effect of cooking method and rice type on arsenic concentration in cooked rice and the estimation of arsenic dietary intake in a rural village in West Bengal, India, Food Addit. Contam., 25/11 (2008) 1345–1352. DOI: 10.1080/02652030802189732
Victor G. Mihucz, Enikö Tatár, István Virág, Chen Zang, Yun Jao, Gyula Záray, Arsenic removal from rice by washing and cooking with water, Food Chemistry 105 (2007) 1718–1725. DOI: 10.1016/j.foodchem.2007.04.057
M.K. Sengupta, M.A. Hossain, A. Mukherjee, S. Ahamed, B. Das, B. Nayak, A. Pal, D. Chakraborti, Arsenic burden of cooked rice: traditional and modern methods, Food Chem. Toxicol., 44 (2006) 1823-1829. DOI: 10.1016/j.fct.2006.06.003
M. Azizur Rahman, H. Hasegawa, M. Arifur Rahman, M. Mahfuzur Rahman, M.A. Majid Miah, Influence of cooking method on arsenic retention in cooked rice related to dietary exposure, Sci. Total Environ., 370 (2006) 51–60.DOI: 10.1016/j.scitotenv.2006.05.018.