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Cassava Flour, Chips, Bread, and More Contain High Levels of Lead

May 8, 2025 from Consumer Reports:

"Cassava has become a popular gluten-free alternative, but CR’s tests of 27 products found that more than two-thirds of them contain more lead in a single serving than our experts say you should have in a day

"Consumer Reports’ latest tests of 27 products found that for over two-thirds of them, a single serving exceeded the level of lead Consumer Reports’ food safety experts use as a threshold for an acceptable daily intake—some by more than 2,000 percent. CR has tested several categories of foods and spices for heavy metals. With the exception of some spices (for example, certain brands of basil, cinnamon, ginger, thyme, and turmeric), 'we’ve never seen lead levels as high as those we found in some of these cassava foods,' says James E. Rogers, PhD, director of product and food safety research and testing at Consumer Reports.

"Root vegetables—including cassava, carrots, beets, and sweet potatoes—grow in the ground and are known to take up some lead along with other heavy metals and contaminants. There’s nothing about the cassava plant that should make it more likely than other root vegetables to absorb lead, according to Ganga Hettiarachchi, PhD, a professor of soil and environmental chemistry who studies trace metal and nutrient chemistry at Kansas State University in Manhattan. But it is possible that some cassava could be grown in highly polluted areas, or handled or processed in ways that introduce lead, she says.

"Several studies have found that cassava can be a significant dietary source of lead exposure in people who eat it frequently. For example, in a 2015 study in the International Journal of Environmental Research and Public Health, researchers found that cassava grown in one region of Ghana was high enough in lead to raise the risk of health problems among people who ate it regularly.

"had between 200 and just over 600 percent of that level per serving. These should be limited, but they’re okay to eat occasionally. The flour with the lowest lead levels in our tests is Tonomi Cassava Flour; one serving supplies 215 percent of CR’s level of concern. Our experts say it’s okay to have up to three servings of it per week.

"Of course, no one eats flour (cassava or otherwise) straight. Still, when we reviewed several recipes for baked goods made with cassava flour, we saw that consuming that ¼ cup in one sitting isn’t difficult. For example, recipes that yield 12 muffins call for 1½ to 1⅔ cups of cassava flour. That means that 2 muffins would supply about ¼ cup.

"Cassava chips also had high lead levels in our tests. Of the eight products we looked at, two are on our avoid list, and one had lead levels high enough that our experts advise eating no more than one serving per week. The lead levels in an ounce of these three products ranged from about 600 to 1,700 percent of CR’s level of concern. The chips with the lowest lead levels were Goya Yuca Cassava Chips. An ounce supplied 10 percent of CR’s level of concern for lead (see chart here.

"Consumer Reports assumes one serving a day of the product in its risk assessment calculations."