Experts say consuming balsamic and red wine vinegars may pose a health risk, especially to children, because vinegars have been found to contain small amounts of lead, according to a recent story in Environmental Health News.

The news organization reported that eating one tablespoon a day of some balsamic or red wine vinegars may increase a young child’s lead level by more than 30 percent.

Small amounts of lead make their way into balsamic and red wine vinegars either during production or through heavy metals in the soil. In California, vinegars that exceed lead levels of 34 parts per billion must contain a warning sign as a result of the state law known as Proposition 65, which requires that consumers be notified when products contain chemicals that could cause cancer, birth defects or reproductive toxicity.

Last week, Environmental Health News bought two balsamic vinegars in San Francisco and submitted them to an independent lab for lead testing.

Even though both bottles had warning labels on them, both were found to be below the amount allowed by the state of California, possibly because lead in food products can vary widely.

However, raising blood levels of lead in U.S. children by even just one microgram per deciliter “would result in a large increase in the number of children with learning problems or behavioral problems,” said Bruce Lanphear, a professor of children’s environmental health at Simon Fraser University in British Columbia. 

One microgram is a millionth of a gram, but even the smallest amounts of lead aren’t known to be safe for a child’s developing brain, said Lanphear.

Though children are exposed to lead mostly through old lead-based paint and tap water, lead in food continues to be a major route of exposure.

In addition, since vinegars are acidic, the lead inside is more easily absorbed into the bloodstream. And, the aged varieties produced by the traditional method, which also tend to be more expensive, have the highest levels of lead.

Representatives of the vinegar industry, however, feel that they’re unfairly targeted in the new California legislation since lead is a naturally occurring substance that can also be found in other foods.

Michele Corash, a San Francisco attorney who represents the vinegar industry, said the producers don’t do anything to add lead to their products.

“Grape juice, wine, they all have trace amounts of minerals that are naturally occurring, including lead,” and shouldn’t fall under the purview of Prop. 65, Corash said. “Virtually all foods have trace levels of one or many chemicals.”

In the meantime, some advocacy groups are fighting to lower both federal and state guidelines for lead, arguing that the old standard is based on 30-year-old science. In 1991, the CDC set 10 micrograms per deciliter as a guideline for the amount of lead that is toxic and could trigger neurological problems in children, according to Environmental Health News. 

“If we looked at the data now, it [the allowable level] would drop substantially,” said Jim Donald, chief of reproductive and ecological toxicology at the Office of Environmental Health Hazard Assessment. “Now we know that 2 to 3 micrograms per deciliter or even lower are having a discernible effect in children."