WEDNESDAY, Nov. 30 (HealthDay News) -- The debate over the safety of fruit juice consumed by Americans escalated Wednesday with the release of a Consumer Reports study that found many apple and grape juice samples tainted with arsenic.

The researchers detected the chemical element at levels exceeding federal drinking-water standards in 10 percent of 88 juice samples tested. The samples involved five brands of juice sold in bottles, boxes or cans of concentrate.

"This is very disconcerting on several levels. Parents should be worried," said Dr. Peter Richel, chief of pediatrics at Northern Westchester Hospital in Mount Kisco, N.Y. "Hearing this should make parents say no to juice."

Most of the arsenic detected was inorganic, meaning it's known to cause bladder, lung and skin cancer. It can also up the risk of heart disease and type 2 diabetes, and some reports have stated that arsenic exposure can affect brain development in children.

Concerns about apple juice safety arose in September when Dr. Mehmet Oz, host of "The Dr. Oz Show," said that about one-third of apple-juice samples he'd tested had arsenic levels exceeding 10 parts per billion (ppb), which is the limit for drinking water. There are no federal limits for arsenic in juice or foods.

The U.S. Food and Drug Administration (FDA) responded with a statement that it "has every confidence in the safety of apple juice."

But rather than quell the debate, the FDA's response may have spurred Consumer Reports to do its own fruit-juice testing. The results are published in its January issue.

Arsenic levels in the grape juice samples were even higher than in the apple juice -- with the highest nearly 25 ppb, more than twice the limit for drinking-water safety, the researchers found.

Arsenic is a natural element that can contaminate groundwater used for drinking and irrigation. But it's also used for industrial and agricultural purposes, which increases individual exposure. Chicken, rice and even baby foods have been found to contain inorganic arsenic, the researchers said.

The Consumer Reports research also discovered that 25 percent of apple juice samples had lead levels higher than that recommended by the FDA for bottled water. No federal limits exist for lead in juice.

Responding to Wednesday's report, the Juice Products Association issued a statement saying that juice is safe for all consumers, adding the industry "adheres to FDA guidelines and juice products sold in the U.S. meet and will continue to proactively meet or exceed the federal standards," the Los Angeles Times reported.

In a related analysis using government data, Consumer Reports researchers found that people who reported recently drinking apple juice or grape juice had about 20 percent more arsenic in their urine than non-drinkers.

Consumers Union, the advocacy arm of Consumer Reports, is urging the FDA to set arsenic and lead standards for both apple and grape juice, especially given that inorganic arsenic has been detected in other foods.

Lead in juice should be limited to 5 ppb as it is for bottled water, while arsenic in juice should not exceed 3 ppb, Consumers Union stated.

The group also encouraged parents to limit their children's consumption of juice per guidelines from the American Academy of Pediatrics: no juice for children under 6 months of age, no more than 4 to 6 ounces daily for children under the age of 6 years, and no more than 8 to 12 ounces for older children. They also recommend diluting juice with water.

But the presence of a potentially fatal element is only one reason children should be drinking little or no juice, said Richel.

"Juices are empty calories," he said. "They're laden with sugar and [carbohydrates] that lead to childhood obesity, and if children are allowed to consume juice after juice after juice, that can replace the balanced consumption of dairy and solids."

A poll conducted by Consumer Reports found that 35 percent of children age 5 years and younger drink more juice than recommended.

More information

The U.S. Environmental Protection Agency has more on arsenic in drinking water.