1. How is Arsenic in Rice affecting our health?
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
How is Arsenic in Rice affecting our health?
Tracy Punshon Ph.D.
Dartmouth College
Dan Leffler
Celiac Center at BIDMC

2. Very poor: purely hypothetical
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Scale of Scientific Certainty
Good, lots of data
Arsenic as an environmental pollutant:
The different forms of arsenic, from safe to toxic forms
Sources of arsenic pollution
Arsenic in rice
How much arsenic is in our food?
How much arsenic should we eat?
Detailed look at arsenic in rice
Poor: not much data
Health effects from dietary arsenic exposure
Nutrients important for arsenic metabolism
What do we do now?
Study arsenic exposure in Celiac Disease patients on gluten-free diets
Partner with the community to reduce exposure and enhance nutritional intake to address arsenic exposure
Very poor: purely hypothetical

3. Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
What is arsenic?
A naturally-occurring metalloid found in rock, soil, water, plants, animals and air.

4. DIMETHYLARSINIC ACID (DMA)
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
The many forms of arsenic
The toxicity of arsenic is a function of its chemical form (‘species’) µg mg g
per serving µg mg g
per serving
ARSENITE &
DIMETHYLARSINIC ACID (DMA)
ARSENOBETAINE
Median lethal dose:
Arsenite: mg/kg
DMA: ,600 mg/kg
NONE FOUND

5. The many forms of arsenic
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
The many forms of arsenic
Acute
toxicity
The toxicity of arsenic is a function of its chemical form (‘species’)
HIGH
Inorganic Arsenic
No carbon
Organic Arsenic
Carbon
Arsenic
LOW
Dimethylarsinic acid: DMA
Monomethylarsonic acid: MMA
3 chemical bonds
Arsenite
Arsenate
5 chemical bonds
Arsenobetaine; AsB
Arsenosugars
Arsenolipids
16 chemical forms relevant to biological systems
100 found in nature

6. Where does arsenic come from?
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Where does arsenic come from?
NATURE
HUMAN ACTIVITIES
Burning coal for energy
Mining metals
Metal smelting operations
Pesticide application
Glass manufacture
Disposal of wastewater sludges
Pharmaceutical waste
Livestock dips
Phosphate fertilizer application
Wood preservatives
Chemotherapeutic drugs
Bedrock
568 known arsenic containing minerals
Groundwater
Drilling of groundwater tube wells in SE Asia “largest mass poisoning in history”

7. 99% 1% How are we exposed to arsenic?
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
How are we exposed to arsenic?
99% 1%

8. “USA long grain rice had the highest mean arsenic level…”
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Rice is an arsenic-accumulating plant
Environmental Science & Technology 39: 2005
“USA long grain rice had the highest mean arsenic level…”
“arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets”

9. A detailed look at arsenic in rice
Processed ingredient
Common name
Anatomy
husk
rice bran oil
brown rice syrup
brown rice flour
brown rice
bran
pericarp
tegumen
aleurone
rice flour
rice starch
rice syrup
puffed rice
rice protein concentrate
white rice
grain
endosperm
Organic
arsenic
germ
embryo
Inorganic
arsenic
‘embryo rice’
rice germ
rice germ oil
ovular
vascular
trace
A detailed look at arsenic in rice

10. Parboiling bran grain Nutrients germ Common name Anatomy
Parboiled rice
(also called ‘converted rice’) is rice that has been partially boiled in the husk.
The three basic steps of parboiling are soaking, steaming and drying.
These steps make rice easier to process by hand, boost its nutritional profile and change its texture.
Common name
Anatomy
husk
bran
pericarp
tegumen
aleurone
Nutrients
grain
endosperm
germ
embryo
ovular
vascular
trace

11. Arsenic regulation in drinking water and food
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Arsenic regulation in drinking water and food
Drinking water: EPA limit 10 µg/L (ppb)
REGULATION
mg/kg = parts per million ‘ppm’ or
1¼ soda bottles/Olympic sized swimming pool
µg/kg = parts per billion ‘ppb’
½ teaspoon/Olympic sized swimming pool
European Union
INORGANIC ARSENIC
White rice 0.2 ppm
Infant rice 0.1 ppm
EPA Integrated Risk Information System Currently under revision
Oral reference dose (daily exposure range for no appreciable risk over a lifetime exposure)
0.3 μg inorganic arsenic/kg body weight/day
Range = μg Asi/kg bw/day
California Proposition 65
Daily intake level for 1:100,000 cancer risk
No significant risk level for daily intake of inorganic arsenic is 10 μg
FDA
Proposed action limit
Infant rice cereal should not contain more than 0.1 ppm (100 ppb) inorganic arsenic
REGULATION

12. The amount of arsenic in serving from eating whole grain rice
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
The amount of arsenic in serving from eating whole grain rice

13. Inorganic arsenic per serving in common rice-containing products
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Inorganic arsenic per serving in common rice-containing products
10 µg

14. Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon

15. Bladder cancer in New England related to drinking water arsenic
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Bladder cancer in New England related to drinking water arsenic

16. Low level exposure and decreased IQ
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
Low level exposure and decreased IQ
Exposure to drinking water As > 5 µg/L was associated with decrease in IQ of 5 -6 points
Wassermann et al. Environ Health Apr 1;13(1):23. doi: / X

17. MONOMETHYLARSONIC ACID
Annual Meeting of the New England Celiac Organization, October 16, 2016
Tracy Punshon
‘One Carbon’ arsenic metabolism: Nutrients and genes
arsenic-3 methyl transferase (AS3MT)
INORGANIC
ARSENIC
FOLATE
METHIONINE
BETAINE
CHOLINE
CH3
AS3MT
B12
MONOMETHYLARSONIC ACID
(MMA)
CH3
Iron
Zinc
Selenium
DIMETHYLARSINIC ACID
(DMA)

18. C-FARR Charge
Develop a set of policy-relevant questions or uncertainties for scientists to consider