Marijuana users have statistically higher levels of lead and cadmium in their blood and urine than people who do not use weed, a new study found.
The study which was published Wednesday in the journal Environmental Health Perspectives, used data between 2005 and 2018 collected by the annual National Health and Nutrition Examination Survey.
According to lead author Tiffany Sanchez, an assistant professor of environmental health sciences at Columbia University Mailman School of Public Health in New York City, what makes the new study “unique” is that the blood and urine tests of 7,254 people who used marijuana in the last 30 days were examined for levels of heavy metals — most studies simply measured metal levels in the cannabis plants, and not the people using marijuana.
“Compared to non-users, marijuana users had 27% higher levels of iron in their blood, and 21% higher levels in their urine… Marijuana users also had 22% higher cadmium levels in their blood than non-users, and 18% higher levels in their urine… Both cadmium and lead stay in your body for quite a long time. Cadmium is absorbed in the renal system and is filtered out through the kidney. So, when you’re looking at urinary cadmium, that’s a reflection of total body burden, how much you have taken in over a long period of chronic exposure,” she noted.
There is no safe level of lead in the body, according to the US Environmental Protection Agency. Cadmium has been linked to kidney disease and lung cancer in people and fetal abnormalities in animals. According to the Cleveland Clinic, heavy metals bind to cells in the body, limiting their function. They have been linked to cancer, chronic disease, and neurotoxic effects.
“Immunocompromised people, such as those going through chemotherapy, may be at greater risk from metal exposure or from other common cannabis contaminants like molds. However, this is very much an understudied area,” Sanchez pointed.
Heavy metals are not just in marijuana — tobacco smokers are exposed to even more types of toxins. E-cigarettes, for example, contain high aerosol levels of nickel, chromium, lead, and zinc, while researchers have found e-liquids and the tanks of e-cigarettes contain arsenic, lead, nickel, tin, manganese, copper, and chromium.
