High-selenium Lentils Versus Arsenic Toxicity

Arsenic Poisoning Clinical Trial

Official title:

Mitigating Arsenic Toxicity in Bangladeshi People by Supplementing Their Diets With High Selenium Lentils

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02429921
• Other study ID #: REB13-1211_MOD1
• Status: Completed
• Phase: N/A
• First received: April 21, 2015
• Last updated: March 29, 2017
• Start date: October 2015
• Est. completion date: September 2016

Study information

• Verified date: March 2017
• Source: University of Calgary
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

About 45 million people in Bangladesh are chronically exposed to unacceptable levels of arsenic in their drinking water. Chronic arsenic poisoning leads to cancers, and vascular diseases.

This dietary trial intends to test the potential of high-selenium lentils, consumed as lentil soup, in reducing the arsenic body burden in an exposed Bangladeshi population, and in improving the overall health status.

Arsenic-exposed families will be assigned to one of two groups. One group will eat lentils (50g/person/day) that are naturally high in selenium, the other group will receive lentils with low selenium content. This 6 months trial is randomized and double-blinded.

Description:

Chronic arsenic (As) poisoning is a worldwide public health problem. Up to 100 million people worldwide, are chronically exposed to dangerously high concentrations of As in their drinking water and food supply. Bangladesh is facing a major public health challenge - contamination of groundwater by arsenic (As). Since tube well water contamination by As was discovered in Bangladesh in the 1990s, As in drinking water has been reduced by 40%, yet approximately 45 million Bangladeshis remain at risk from high As concentrations greater than the WHO guideline value of 10 µg/L in the well water. The annual cost to treat As related health problems in Bangladesh is currently estimated up to $77.5 million. Micronutrient-deficient (e.g. Selenium) soils lead to less nutritious local foods, which becomes a partner in crime exacerbating the toxic burden incurred by As exposure.

Selenium (Se) is a trace element that is an essential component of several metabolic pathways controlling immune function. Se and As work antagonistically in the body by competing in many biological functions. Arsenic added to animal diets has been known to counteract Se toxicity/activity in animals since the 1930s. Se interacts with As to form a complex; excessive Se excretion can occur as result of Se/As complex formation under condition of chronic As ingestion and low dietary Se ingestion. This scenario may further accelerate Se depletion. Again, since Se can form a complex with As, Se supplementation, in principle, can reduce As toxicity and also decrease effects of As exposure on many other parameters, such as oxidative stress, immunotoxicity etc.

Supplementation of Se as pills is currently used to treat arsenicosis. But pills are not often well received by people and are expensive for low-income families. Lentils are a common food in Bangladesh and the country already imports lentils from Canada. Saskatchewan (SK) grown lentils are rich in Se, mostly in form of L-selenomethionine, which is highly bioavailable. The Saskatchewan lentils have mean selenium levels between 425-672 µg/kg, with some regions where lentil selenium levels go up to 1884 µg/kg. These high Se lentils, incorporated into the daily meals of As-exposed Bangladeshi families, may help mitigate the symptoms of long-term As poisoning in a cost-effective, uncomplicated, and nutritionally beneficial way.

Red lentils for this trial were grown in Saskatchewan, Canada (Se = 854 µg/kg) and Idaho, USA (Se = 0.043 µg/kg). Other nutrients will be measured in both crops of lentils at the UofS before dispatching to families in Bangladesh. High-Se and low-Se lentils will be packed in two different coloured packets and will be given to the designated families. The investigators as well as the field staff will be blinded to the types of lentils/dahl being given to each family. 65g lentils per person/day will be measured with a cup by the female family head, who typically cooks the moshur dahl (lentil soup) daily for the whole family. 65g high-Se lentils provide 55 µg Se, which is the recommended daily allowance of 55 µg/person/day.

Sampling procedure and Data collection: At the start, at mid-term and the end of the trial (Table 1), household water samples, plus hair, blood, faeces and on-spot urine samples will be collected from each individual.

Water (20 ml): Currently used drinking water for measurement of arsenic, and other toxic and essential elements. Water will be acidified before storage at pH <2.0 in trace element free tubes at room temperature.

Urine (15-20 ml): Urine will be collected in trace element free tubes, aliquoted and stored in -80°C.

Stool (5-10 g): Stool will be collected in trace element free tubes and stored in -20°C.

Blood (5 ml/visit): Blood will be collected using a sterile needle and syringe in trace element free vacutainer tubes. Blood samples will be sent to Dhaka Lab on the same day in cool boxes and separated into plasma and cells, aliquot of plasma will be stored at -80°C. Buffycoat cells will be stored in RNALater in -80°C freezer. Whole blood (100 ul) will be stored in -80°C.

Hair: Hair from the back of the head will be collected (about 0.2 g) for analysis of As, as hair As is a suitable marker for long term exposure.

Laboratory Methods:

Metals: Se will be measured in blood by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Arsenic in hair, stool and urine samples will be measured by Hydride Generation Atomic Absorption Spectrometry (HGAAS) after acid digestion of samples.

Oxidative stress and antioxidant status : the investigators will measure 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG), a major product of ROS-induced oxidative stress, in urine/plasma of children using commercial ELISA kits. Reduced glutathione (GSH) is considered as an important scavenger of reactive oxygen species (ROS), and its ratio with oxidized glutathione (GSSG) is used as a marker of oxidative stress. The antioxidant status (GSH/GSSG) in whole blood will be assessed by measuring GSH and GSSG using commercial kits.

Lung inflammation: The investigators will measure fractional exhaled nitric oxide (FENO) in participants (≥9 yrs) as a marker of allergic lung inflammation. Monitoring FENO is simple and non-invasive with the use of a hand held small equipment. FENO will be measured online by the single breath technique according to published guidelines (ref) and manufacturer's instructions, with a NIOX MINO®. FENO will be recorded as mean value from two successive reproducible readouts. FENO data will be given as p.p.b. NIOX MINO uses IR communication for transfer of participant data to a PC using the software NIOX MINO Data Manager. FENO is usually high in individuals with current allergic asthma or rhinitis.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 400
• Est. completion date: September 2016
• Est. primary completion date: September 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 14 Years and older

Eligibility

Inclusion Criteria:

• low, moderate and high arsenic levels in tube well water, that the household uses. If tube well water exceeds the national standard of 50 ppb, families will be advised to switch to another well in their proximity with lower Arsenic levels, if available.

Exclusion Criteria:

• Families that have very low arsenic levels (below US standard of 10 ppb) in their well water will not be enrolled.

Related Conditions & MeSH terms

• Arsenic Poisoning
• Poisoning

Intervention

Dietary Supplement:
• high-selenium lentils
lentils grown on naturally selenium-rich soils in the Canadian Prairies
• Low-Se lentils
lentils grown on selenium-deficient soils in Idaho, USA.

Locations

Country	Name	City	State
Bangladesh	Field Office, International Centre for Diarrhoeal Disease Research, Bangladesh	Dhaka

Sponsors (2)

Lead Sponsor	Collaborator
University of Calgary	International Centre for Diarrhoeal Disease Research, Bangladesh

Country where clinical trial is conducted

Bangladesh, 

References & Publications (5)

Gailer J, George GN, Pickering IJ, Prince RC, Younis HS, Winzerling JJ. Biliary excretion of [(GS)(2)AsSe](-) after intravenous injection of rabbits with arsenite and selenate. Chem Res Toxicol. 2002 Nov;15(11):1466-71. — View Citation

Thavarajah D, Ruszkowski J, Vandenberg A. High potential for selenium biofortification of lentils ( Lens culinaris L.). J Agric Food Chem. 2008 Nov 26;56(22):10747-53. doi: 10.1021/jf802307h. — View Citation

Thavarajah D, Vandenberg A, George GN, Pickering IJ. Chemical form of selenium in naturally selenium-rich lentils (Lens culinaris L.) from Saskatchewan. J Agric Food Chem. 2007 Sep 5;55(18):7337-41. Epub 2007 Aug 9. — View Citation

Thavarajah, D., et al. (2011), 'A global survey of effects of genotype and environment on selenium concentration in lentils (Lens culinaris L.): Implications for nutritional fortification strategies', Food Chemistry, 125 (1), 72-76.

Zeng H, Uthus EO, Combs GF Jr. Mechanistic aspects of the interaction between selenium and arsenic. J Inorg Biochem. 2005 Jun;99(6):1269-74. Review. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	arsenic body burden	Urine, feces, and hair samples of participants will be tested for arsenic content.	week 12
Secondary	Antioxidant status	Blood specimen will be tested for glutathione (ox/red) levels.	week 24
Secondary	oxidative damage	Blood specimen will be tested for 8-OHdG, a marker for oxidative DNA damage.	week 24
Secondary	serum lipid levels	Serum will be analyzed for triglyceride, total cholesterol, HDL- and LDL-cholesterol.	week 24
Secondary	Lung inflammation test	Participants will exhale into a NIOX Mino device, which measures the nitric oxide level as marker of lung inflammation	week 12
Secondary	Health and compliance questionnaires	Health questionnaire (and initial sociodemographic questionnaire) will be filled in by participant every two weeks to assess overall health, and lentil consumption will be assessed weekly.	biweekly (health) for 6 months
Secondary	Body mass index	Examination by health professionals: Body mass index	week 24
Secondary	Blood pressure	Examination by health professionals: blood pressure	week 24

External Links

•   WHO: Arsenic: Fact Sheet No. 372, December 2012. 2012.