Blazing could increase the levels of heavy metals in blood

Researchers discovered greater amounts of lead and cadmium in marijuana smokers, both of which have been related to long-term health problems. 
Mrigakshi Dixit
Cannabis buds on scale for weight measuring using tweezers
Cannabis buds on scale for weight measuring using tweezers


Marijuana is the third most often used narcotic on a global scale. A recent study revealed that marijuana users have much higher levels of heavy metals in their blood and urine than non-users.

Researchers discovered greater amounts of lead and Cadmium related to long-term health problems. 

The cannabis plant is considered a metal hyperaccumulator, which means it can absorb and accumulate particular metals present in soil, fertilizers, water, and pesticides. These metals can also end up in human bodies when they are consumed in the form of drugs. 

High amount of metals

This result was reached after studying approximately 7,200 persons. 

A team of researchers, including those from Columbia University, meticulously evaluated blood and urine samples gathered between 2005 and 2018. The samples were taken as part of the National Health and Nutrition Examination Survey, an initiative of the National Center for Health Statistics. 

Reportedly, around 358 people who reported using marijuana in the previous 30 days had blood lead levels that were 27 percent higher than those who claimed not to use either marijuana or tobacco. 

On the other hand, marijuana users' blood was discovered to be tainted with 22 percent greater amounts of Cadmium. 

Higher quantities of metals were also detected in their urine samples. 

Long-term health risks from these two metals 

Long-term lead exposure in humans can lead to various adverse health effects, including neurological problems (cognitive and behavioral issues), high blood pressure, joint discomfort, and kidney damage. 

The World Health Organization (WHO) has classified Cadmium as a human carcinogen. Even minor exposure to this metal — through tobacco smoke — can cause renal problems and weaker bones.

These metal traces linger in the body for prolonged periods, even after a person has ceased using marijuana. 

However, the survey did not specify whether marijuana was consumed as edibles or joints. However, the authors warn that due to the substantially increased absorption rate associated with inhalation, breathing lead is more dangerous than consuming it through food.

Despite numerous states legalizing recreational and medical marijuana use, this substance remains prohibited at the federal level in the United States.

The findings have been reported in the journal Environmental Health Perspectives

Study abstract:

Background: Marijuana is the third most used drug in the world.

Objectives: Because the cannabis plant is a known scavenger of metals, we hypothesized that individuals who use marijuana will have higher metal biomarker levels compared with those who do not use.

Methods: We combined data from the National Health and Nutrition Examination Survey (2005–2018) for lowercase italic n equals 7,254n=7,254n=7,254 participants, classified by use: non-marijuana/non-tobacco, exclusive marijuana, exclusive tobacco, and dual marijuana and tobacco use. Five metals were measured in blood and 16 in urine using inductively coupled plasma mass spectrometry; urinary metals were adjusted for urinary creatinine.

Results: Participants reporting exclusive marijuana use compared with non-marijuana/non-tobacco use had statistically significantly higher mean cadmium levels in blood [1.22 micrograms per liter1.22μg/L1.22μg/L (95% CI: 1.11, 1.34); lowercase italic p less than 0.001p<0.001p<0.001] and urine [1.18 micrograms per gram1.18μg/g1.18μg/g (95% CI: 1.0, 1.31); lowercase italic p equals 0.004p=0.004p=0.004] and statistically significantly higher mean lead levels in blood [1/27 micrograms per deciliter1.27μg/dL1.27μg/dL (95% CI: 1.07, 1.50); lowercase italic p equals 0.006p=0.006p=0.006] and urine [1.21 micrograms per gram1.21μg/g1.21μg/g (95% CI: negative 0.006−0.006−0.006, 1.50); lowercase italic p equals 0.058p=0.058p=0.058].

Discussion: Our results suggest marijuana is a source of Cadmium and lead exposure. Research regarding cannabis use and cannabis contaminants, particularly metals, should be conducted to address public health concerns related to the growing number of cannabis users.

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