Pregnancy Warning: Arsenic Exposure from Rice Detected in Pregnant Women in US
A recent study warns that arsenic exposure from rice was detected in a significant number of pregnant women in the U.S. This study highlights the concern of researchers at Dartmouth College who believe that arsenic exposure from eating rice before and during pregnancy is a public health concern due to potential health risks to a developing fetus. They address the issue that there is a need for regulatory standards controlling the allowable levels of arsenic in our food to keep arsenic exposure within safe levels—especially for pregnant women in the U.S.
In a recent article published in the scientific journal Proceedings of the National Academy of Sciences (PNAS), researchers at Dartmouth College reveal their discovery that pregnant women who eat rice may be exposing their fetuses to levels of arsenic that are dangerously high.
Rice plants are well-known in the scientific community as a plant that has the ability to extract and accumulate naturally occurring arsenic from the soil. Previous studies have demonstrated that this is an endemic public health problem in countries like Bangladesh and India where arsenic contaminates the water that feeds rice plants in paddies. However, this is not just a foreign country problem due to lack of regulation and safeguards—but a homegrown one as well. Previous studies have shown that rice grown in the U.S. contains varying levels of arsenic depending on its geographic location where it is farmed.
Exposure to arsenic is linked to numerous adverse health effects such as cancer, skin lesions and cardiovascular disease. The long term effect of chronic low dose exposure is still an understudied problem, but is believed by epidemiologists to be responsible for hampered immune function and increased lung cancer mortality resulting from arsenic exposure while a fetus is developing in the uterus.
Rice consumption in the U.S. averages to about ½ cup of rice per day, with Asian Americans consuming on average more than 2 cups of rice per day. Health-conscious pregnant women tend to consume more rice than the daily U.S. average.
In the study, the arsenic exposure levels of pregnant women from eating rice were determined by measuring the level of arsenic detected in their urine. A sample of 229 pregnant women from New Hampshire was divided into two groups of test subjects. The test subjects were grouped according to whether they had or had not eaten rice within the past two days prior to collecting their urine samples. Samples of their home tap water used for drinking and cooking the rice were also collected.
According to a news release from Dartmouth College, “This enabled our team to separate the potential for exposure to arsenic from drinking water from that of rice,” says Gilbert-Diamond, one of the co-authors of the paper. The news release states that urinary arsenic analyses was performed at the University of Arizona by co-author Professor A. Jay Gandolfi and colleagues and water testing was performed at Dartmouth’s Trace Element Analysis Facility by collaborator Brian Jackson Ph.D.
What the researchers found were statistically significant differences in arsenic levels between those who ate rice and those who did not. Seventy-three of the rice-eating subjects had a median of 5.27 micrograms per liter of arsenic in their urine in comparison to 156 non-rice eating test subjects who measured at 3.38 micrograms per liter of arsenic in their urine.
The conclusion of the study was that their results demonstrate a need to set regulatory limits on the amount of arsenic allowable in food, noting that China has already placed allowable level limits at 0.15 micrograms of inorganic arsenic per kilogram of food. The researchers of the study state that additional data is needed to determine the health impact of eating rice contaminated with arsenic. They note that several ethnic cultures within the U.S. eat significantly more rice than the average, and that pregnant women may be especially vulnerable due to the potential harmful effects of arsenic on their developing fetuses.
Reference: PNAS December 5, 2011