A Dietary Solution to Arsenic Poisoning in Bangladesh
2016 International Conference on Pulses
For Health, Nutrition and Sustainable Agriculture for Drylands Marrakesh, Morocco
April 2016
Judit E.G. Smits, DVM, PhDProfessor, Ecosystem & Public Health
Faculty of Veterinary Medicine
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As
As
As
As
Coal with high As content mountainous regions of China
Emerging in more water sources globally . . . .
In drinking wateremerging in areas
throughout Europe, North & South America
Mine tailings & dust
Known areas with natural arsenic contamination Ravenscroft et al. 2008
Health problems associated with arsenicosis
Hyperkeratosis & hyperpigmentation(thickening & blackening of skin)
Peripheral vascular disease- arterial blockage leading to gangrene of extremities
Cardiovascular disease - arsenic blocks major blood vessels
Hepatic disease – similar in humans & experimental animals
- hepatomegaly, fatty change
- liver fibrosis - decreased GSH
- increased oxidative damage
(MDA in liver, 8-OHdG in plasma)
Pulmonary & bladder cancer
70
100
130
160
190
220
250
280
MDA (nmol/mg of
protein)
PCC (ng/mg of
protein)
8-OHdG (ng/mg of
protein)
Rela
tive D
iffe
rence (
%)
CTR 0.4ppm 4ppm 40ppmControl vs arsenic 0.4, 4, 40ppm
MDA 8-OHdG
Liver damage from arsenic
Se builds the major anti-oxidant of the body (as glutathione – GSH)
controls free radical damage produced by normal metabolism
free radicals are much higher in malnourished people (+ - As toxicity)
Se enhances immune surveillance vs neoplastic (cancer) cells
Much of the earth’s soils
are deficient in Se lentil production
area in North America
IV injection of As & Se separately, produces the conjugate seleno-bis-arsinium ion (GS)2AsSe] excreted in bile, then feces
Zeng H, Uthus EO, & Combs GF,Jr. (2005) Mechanistic aspects of the interaction between selenium and arsenic. J of Inorganic Biochemistry, 99: 1269-1274.
Gailer J, et al. (2002) Biliary excretion of [(GS)(2)AsSe](-) after intravenous injection of rabbits with arsenite and selenate. Chem Research in Toxicology, 15: 1466-1471.
The story of selenium (Se)
Normal Se Severely deficient Se
Globally - soil is deficient in Se- some ‘hot spots’ have high Se - toxicity problems
- a few regions are just right
Good Se levels in Saskatchewan soils
- old sea bed – high selenium - crops take up selenium in seeds
0
100
200
300
400
500
600
Canada
Bangladesh
India
Australia
USA
Nepal
Syria
Tot
al Se c
once
ntra
tion
( µg.
kg-
1)
Se
medicinal uses to treat diseases such as syphilis
used as a growth promotant in poultry & swine feed
popular means of murder during Victorian times in the 19th century
In 1970’s in BD arsenic started appearing in ‘clean’ tube-well water
As 3+ is the most common form in drinking water in south Asia
in vivo As 5+ is normally reduced to the more toxic form, As 3+ during
metabolism
largest mass poisoning in history: WHO estimates that 140
million people are exposed to As levels > 50 ug/L (US EPA &
WHO limits of <10 ug/L)
History of arsenic
Shahrasti, Chandpur
1) Identify households with As ≥ 100 ppb in tube well water
- 102 wells tested- tube wells 60 – 120 ft deep- 92 As higher than 100 ppb
- 88% with As > 250 ppb
- no influence of well depthon As content
>250 ppb As
drinkingwater
standardAs < 50ppb
Arsenicosis in Bangladesh
Seeking the solution through Saskatchewan lentil
filter to remove arsenic
- defunct 10 yrs ago As
Conjugate
urinary & fecal Asexcretion
Se
WHO efforts for clean water:
Large vessels to collect rain water from roof
icddr.,b colleagues –Shahrasti field station
Lentils in storage inSharasti –
weekly distributionto families
6 Month Dietary Trial in Shahrasti, Bangladesh
Screening
well water
Arsenic ≥
100ppb
Day 1:
Physical exam
sample collection
3 months:
Physical exam
sample collection
6 months:
Physical exam
Sample collection
Physical examinations:
BMI, BP, NIOX MINO® lung inflammation exam
• Bi-weekly morbidity questionnaire
• Weekly lentil consumption log
• Weekly lentil consumption questionnaire
Block randomization
Recruitment:
Socio-demogr. questionnaire
Adult & child consent
Samples:
Macronutrients Sask. Lentils Idaho Lentils
Protein % by weight 26.22 27.73
Starch % by weight 38.00 37.00
TDF % by weight 8.48 6.66
Phytochemicals
Phytic acid g/kg 0.61 0.72
Minerals
Calcium mg/kg 328 378
Potassium g/kg 10.45 10.94
Sodium mg/kg 72 75
Magnesium mg/kg 786 943
Copper mg/kg 9.3 11.4
Iron mg/kg 75.75 65.3
Zinc mg/kg 42.15 51.9
Manganese mg/kg 16.9 14.6
Selenium mg/kg 0.854 0.029
Arsenic mg/kg <0.001 <0.001
Coauthors & Acknowledgements
Regina Krohn, PhD University of Calgary, Calgary, AB, Canada
Rubhana Raqib, PhD icddr,b, Dhaka, Bangladesh
Albert Vandenberg, PhD University of Saskatchewan, Saskatoon, SK, Canada
Funders
Global Institute for Food Security – (Government of Saskatchewan,
University of Saskatchewan, Potash Corp)
Saskatchewan Pulse Crop Development Board
Grand Challenges Canada- Stars in Global Health
