Fruit juice has been falling out of favor for its high sugar content and low nutritional value. Now parents have another reason to pull the plug: heavy metals.

According to a study released on Wednesday by Consumer Reports, measurable levels of cadmium, inorganic arsenic, mercury or lead were found in every single one of the 45 juice products it tested from major brands sold across the U.S. Almost half of the juices had metal levels so high they were deemed โ€œconcerning,โ€ with seven of the products posting heavy metal concentrations high enough to harm children who drink as little as 4 ounces โ€” about half a cup โ€” a day.

โ€œThe risks we assessed were all due to chronic exposure โ€” persistent, daily intake over an extended period of time,โ€ James Dickerson, Consumer Reportsโ€™ chief scientific officer, said in an interview. Whether youโ€™re an adult or a child, โ€œitโ€™s a good idea to try to reduce the amount of non-refrigerated, ready to drink juice.โ€

To be fair, it would be impossible to remove all heavy metals from food and drinks, since some can occur naturally, Dickerson said.

Toxins can find their way into foods through water, air and soil, or they can be added unintentionally at manufacturing plants or in product packaging.

In some of the juices tested, the level of a single metal wasnโ€™t concerning, but combined, they could have an adverse effect on childrenโ€™s developing brain and nervous systems, the report said.

Organic juice, or juice marketed for children, isnโ€™t necessarily safer: Neither group performed any better than other juices, Consumer Reports found. In general, grape juice and juice blends had the highest average heavy metal levels, the report said.

Certain juices from Minute Maid, R.W. Knudsen, Gerber, Welchโ€™s, Mottโ€™s and Juicy Juice were listed as potentially risky at either a cup or half cup a day.

Some in-house juice brands from Trader Joeโ€™s, Walmart, CVS Health Corp. and Whole Foods were also found to be potentially harmful, although some of these same companies โ€” including Whole Foods, Juicy Juice, Gerber, Minute Maid and Mottโ€™s โ€” also had juices listed on the โ€œbetter alternativesโ€ list.

โ€œAll Welchโ€™s juice is safe and strictly complies with all food safety regulations for juice โ€” in the United States and in other countries around the world,โ€ Jackie Lee, senior manager of brand engagement for Welchโ€™s, said in an email. โ€œNaturally occurring elements such as lead and arsenic are present in the soil, air and water. Therefore, they are also found in very low, harmless levels in many fruits and vegetables. Ongoing third-party testing shows that heavy metals in our products are far below federal limits.โ€

Gerber, owned by Nestle, said it uses โ€œsome of the most precise analytical equipment and test methods availableโ€ to carry out regular tests.

The company works with farmers to reduce and limit contaminants, and its juices โ€œmeet our rigorous safety and quality standards, which are based on the latest food safety guidance from sources like the Food and Drug Administration and international health authorities,โ€ the company said in an emailed statement. Gerber said it doesnโ€™t sell products that donโ€™t comply with its safety standards.

The other companies did not respond to requests for comment. The Juice Products Association, a trade group representing the industry, said it hasnโ€™t received a copy of the study from Consumer Reports, making it impossible to respond to specific findings.

โ€œJuice producers make safety a priority 365-days-a-year, and believe the concerns cited by Consumer Reportsโ€™ intermittent testing of selected products are unfounded. Consumers can be assured that juice is safe,โ€ the association said in an emailed statement. โ€œRegardless of where the ingredients are sourced or where the juice is processed, all juice producers are required to manufacture products that comply with FDA regulations.โ€

Thatโ€™s part of the problem, according to Consumer Reports: the U.S. Food and Drug Administration doesnโ€™t have a proposed limit for cadmium in juice and hasnโ€™t finalized the one itโ€™s proposed for inorganic arsenic in apple juice.

Consumer Reports also says the FDAโ€™s guideline for lead is too high. The FDA didnโ€™t immediately reply to a request for comment.

In general, juice consumption has gone down in the U.S., but companies have had a hard time developing substitutes to juice that kids want to drink. Juice has a lot of sugar, and almost none of the beneficial fiber that whole or frozen fruit contain.

โ€œItโ€™s important for families to remember that the beverage kids need the most is water,โ€ said Dr. Steven Abrams, the chair of the American Academy of Pediatrics Committee on Nutrition.