There are two main types of arsenic: organic and inorganic. These terms refer to the chemistry of the arsenic compound; they have nothing to do with pesticide use, as when the term "organic" is applied to foods.

The majority of arsenic the researchers found was inorganic, which is generally thought to be more harmful than organic arsenic. Chronic exposure to low levels of inorganic arsenic has been linked to increased risks of bladder, lung and skin cancer, as well as type 2 diabetes and cardiovascular disease, according to the EPA.

Recent studies have shown that rice can be a major source of arsenic in the diet. The new study highlights the fact that products not normally regarded as containing rice may still harbor significant levels of arsenic, the researchers said.

It is not yet clear whether the arsenic in rice, rice-based products or other foods is harmful to people. However, the levels found in infant formulas are concerning, because of infants' small body size, said study researcher Brian Jackson, of the department of Earth sciences at Dartmouth College in Hanover, NH.

Jackson and colleagues measured the amount of arsenic in 17 infant formulas, 29 cereal bars and three energy shots purchased from stores in New Hampshire.

Two of the infant formulas contained organic brown rice syrup as their primary ingredient. These products had arsenic levels 20 to 30 times that of the other infant formulas.

Some 22 of the cereal bars contained at least one rice product (organic brown rice syrup, rice flour, rice grain or rice flakes) listed as one of the first five ingredients. These bars had levels of arsenic that ranged from 23-128ppb. Cereal bars that did not contain rice had much lower arsenic levels, ranging from 8-27ppb.

The energy "shots", or gel-like blocks, contained between 84 and 171ppb arsenic. All the products had organic brown rice syrup as one of the ingredients. An individual who consumed four of these energy shots would consume more than 10 micrograms of arsenic -- an amount equal to drinking 1 liter of water with arsenic concentration at the current EPA limit.

Of all the study findings, "the data on the infant formulas is most concerning," said Christopher States, a toxicologist at the University of Louisville in Kentucky. The amount of arsenic consumed by an infant could be significant depending on which formula they drank, States said. In addition, the arsenic concentrations in the study were calculated assuming the infant formula powders were prepared for babies to drink with arsenic-free water. Infants who consumed formulas with high arsenic levels that were mixed with arsenic-containing water would be at the greatest risk for potential health effects, States said.

Recent research suggests arsenic exposure early in life may increase the risk for health problems later on. Formula may be a baby's sole food over a critical period of development, and their small size means they may consume more arsenic per kilogram of body weight than an adult eating foods with similar arsenic levels, the researchers said.

It is hard to say what effect arsenic in foods may have on adults, Jackson said. If guidelines are set for acceptable levels of arsenic in food, they may be higher than most of the levels found in this study, around 200ppb, Jackson said.

"I don't think eating the occasional cereal bar has any real risk to it," Jackson said. For those concerned about arsenic exposure, Jackson recommends making sure meals are not rice-based. For parents, Jackson said to avoid infant formulas that contain rice syrup.

 From the February 17, 2012, Prepared Foods' Daily News.