Cadmium in food: true, false, uncertain

It’s every­where: in pasta, veget­ables, chocol­ate, cer­eals… Cad­mi­um, a poten­tially tox­ic heavy met­al, is believed to be present in nearly the entire pop­u­la­tion. Although it has always been present in the envir­on­ment, the levels meas­ured in our bod­ies have reportedly skyrock­eted in recent dec­ades, a trend that wor­ries sci­ent­ists. Indeed, above a cer­tain con­cen­tra­tion, its effects on the body are believed to be harm­ful, and it has already been linked to sev­er­al con­di­tions of vary­ing severity.

TRUE

Sébas­tien Denys. Cad­mi­um occurs nat­ur­ally in the ground, par­tic­u­larly of agri­cul­tur­al land, since it is an ele­ment found in the Earth’s crust that forms soil as it breaks down. In addi­tion to this nat­ur­al source, there is also an anthro­po­gen­ic con­tri­bu­tion. Cad­mi­um is present in many indus­tri­al emis­sions as well as in widely used phos­phate fer­til­isers. Crops that come into con­tact with the soil then absorb cad­mi­um through their roots and trans­fer it to the edible parts of the plant.

Géraldine Carne. In its third Total Diet Study (étude de l’alimentation totale – EAT 3), pub­lished in Janu­ary 2026, ANSES shows that cad­mi­um was detec­ted in 89% of food samples. It is found in grain products, bread, cook­ies, pastries, and pasta. It is also present in pota­toes, veget­ables, chocol­ate, sea­food, and organ meats.

FALSE

GC. When we cor­rel­ate cad­mi­um con­tam­in­a­tion levels with the fre­quency of con­sump­tion of each food, we identi­fy cer­tain foods as major con­trib­ut­ors to the population’s over­all expos­ure. The foods with the highest con­cen­tra­tions of cad­mi­um are not neces­sar­ily the ones that cause the most tox­icity. This is the case, for example, with chocol­ate, sea­food, and organ meats, which, on a pop­u­la­tion-wide basis in France, account for only a small por­tion of the diet. On the oth­er hand, staple foods such as grains, bread, pasta, cook­ies, pastries, pota­toes, and cer­tain veget­ables (such as tubers) are not the most con­tam­in­ated, but they con­trib­ute the most to cad­mi­um expos­ure because they are con­sumed daily.

UNCERTAIN

GC. It is import­ant to note that cad­mi­um has a very long bio­lo­gic­al half-life, ran­ging from 10 to 30 years. This means it takes dec­ades for it to dis­ap­pear from the envir­on­ment or the human body. The first step in lim­it­ing expos­ure is there­fore to address the source by avoid­ing any expos­ure, how­ever min­im­al, par­tic­u­larly in the soils where the food­stuffs that con­trib­ute most to pop­u­la­tion con­tam­in­a­tion are grown. Even a very small amount added to the soil con­trib­utes to its bioac­cu­mu­la­tion and per­petu­ates the cycle of envir­on­ment­al contamination.

Yann Le Bodo. ANSES recom­mends using phos­phate sources with low cad­mi­um con­tent. Cad­mi­um is nat­ur­ally present in the rocks from which fer­til­isers are pro­duced, and since it is not removed dur­ing the man­u­fac­tur­ing pro­cess, it ends up in the fin­ished product that is applied to the soil. Its pres­ence is obvi­ously undesir­able, as it provides no bene­fit to plants. Cur­rently, France sources its phos­phate rock primar­ily from North Africa, where phos­phate rock depos­its may have high cad­mi­um levels.

When it is not pos­sible to source rock with lower cad­mi­um con­tent, a second option is to use cad­mi­um-remov­al pro­cesses that allow some of this met­al to be removed dur­ing fer­til­iser pro­duc­tion at a reas­on­able cost. Finally, whenev­er pos­sible, ANSES recom­mends remo­bil­ising the phos­phor­us already present in the soil by, for example, return­ing crop residues to the field.

Thibault Ster­ck­e­man. To pre­vent cad­mi­um from being absorbed by plants, one can adjust the soil’s acid­ity. The pH can be reg­u­lated by apply­ing lime or by adjust­ing the amount of humus used to cov­er the fields. How­ever, crop man­age­ment is already well optim­ised in this regard, so it will be dif­fi­cult to fur­ther reduce the trans­fer of cad­mi­um from the soil to cul­tiv­ated plants. It is also pos­sible to select and grow cer­tain veget­ables that accu­mu­late less cad­mi­um, but this requires a long and costly pro­cess of plant breed­ing. It takes about ten years to devel­op a new variety.

TRUE

SD. Santé pub­lique France has shown that between 2006 and 2016, cad­mi­um expos­ure in the pop­u­la­tion nearly doubled. We will con­tin­ue to mon­it­or this trend in our next study (called Albane), the res­ults of which will be avail­able next year. While we meas­ure cad­mi­um levels in the urine of test sub­jects, ANSES assesses the con­cen­tra­tion of this heavy met­al dir­ectly in food through its EAT reports. Des­pite using a com­pletely dif­fer­ent meth­od, ANSES sci­ent­ists have also observed an upward trend. These res­ults show that we must act quickly to under­stand the cause of this increase.

FALSE

TS. Des­pite excess­ive expos­ure among the French pop­u­la­tion, cad­mi­um levels in soil gen­er­ally remain below reg­u­lat­ory thresholds. The nat­ur­al con­cen­tra­tion of cad­mi­um in the upper con­tin­ent­al crust is 0.1 mg/kg. This is very low, fall­ing with­in the ultra-trace range. In the sed­i­ment­ary rocks from which soils are formed, it is approx­im­ately 0.2 mg/kg. Finally, in the French soil that we till and in which we plant crops, it aver­ages 0.3 mg/kg. This increase stems from atmo­spher­ic con­tam­in­a­tion, agri­cul­tur­al inputs, and nat­ur­al enrich­ment. Indeed, it can­not be ruled out that the forest that covered our soils for mil­len­nia acted as a pump, draw­ing cad­mi­um from the depths to the sur­face. All this to say that cur­rent levels in our fields are not out of the ordinary.

UNCERTAIN

TS. We can­not explain why cad­mi­um expos­ure in the pop­u­la­tion has skyrock­eted over the past dec­ade, between 2006 and 2016, while cad­mi­um con­cen­tra­tions in the soil have remained rel­at­ively stable. Even if there has been recent con­tam­in­a­tion due to fer­til­isers, humans have always been exposed to levels that are in the same order of mag­nitude as those we see today. Hence, it is sur­pris­ing that this ele­ment has sud­denly proven to be so tox­ic. These res­ults war­rant fur­ther con­firm­a­tion and explan­a­tions regard­ing the under­ly­ing mechanisms.

SD. We know that phos­phate fer­til­isers con­tain cad­mi­um. How­ever, we have not yet demon­strated that the increase in cad­mi­um expos­ure among the pop­u­la­tion is due to increased use of these fer­til­isers. Between the two stud­ies con­duc­ted by Santé pub­lique France between 2006 and 2016, it is also pos­sible that there were ana­lyt­ic­al biases, since meth­ods have evolved over the past 10 years.

TRUE

SD. Cad­mi­um is clas­si­fied as a def­in­ite car­ci­no­gen by the Inter­na­tion­al Agency for Research on Can­cer (IARC), par­tic­u­larly for the lungs. It also has harm­ful effects on the res­pir­at­ory sys­tem, kid­neys, and bones. Because it accu­mu­lates in the body, cad­mi­um can cause effects long after ini­tial expos­ure, even at low doses.

FALSE

SD. Cad­mi­um is nat­ur­ally present in the envir­on­ment. We are there­fore inev­it­ably exposed to it and have been for as long as any­one can remem­ber. The same is true for all trace metals, such as arsen­ic, for example. Tox­icity simply depends on the con­cen­tra­tion of the met­al in ques­tion in the envir­on­ment. Some areas have high­er levels of cad­mi­um than oth­ers. This is par­tic­u­larly true of former min­ing or indus­tri­al areas. But no mat­ter where you live, you will be exposed to it.

UNCERTAIN

SD. Some stud­ies estab­lish a link between cad­mi­um expos­ure and pan­cre­at­ic can­cer, but to date, its effect has not been proven. Numer­ous research pro­grams are test­ing this hypo­thes­is, but since this dis­ease can be caused by sev­er­al eti­olo­gic­al factors, it is dif­fi­cult to isol­ate the impact of cad­mi­um expos­ure and to assert that it is the cause. It is a ser­i­ous line of inquiry, but it requires fur­ther confirmation.

Interview by Jimmy Leyes