Cadmium in Our Food Can Cause Kidney Damage

Cadmium is a heavy metal that occurs naturally in the Earth’s crust, and is released into the environment as a result of weathering of rocks and volcanic emissions. Human activities such as the smelting of metals, the burning of fossil fuels and use of fertilisers have increased the levels of cadmium in water, soil and living organisms.

Cadmium enters the food chain because it is taken up from the soil by plants, which are then eaten by animals. Fish and shellfish can take up cadmium from their diet and from seawater. While there is no immediate harm to health caused by cadmium in food, it can cause problems if consumed at high levels over a prolonged period of time. It accumulates in the kidney and can eventually cause kidney damage and bone demineralisation later in life.

We get most of our cadmium from eating cereals and cereal products, vegetables and potatoes – these foods are low in cadmium, but contribute the most because consumption of them is high. Cadmium can be much higher in some foods such as offal and some seafood but as most people eat these much less than other foods they are not significant overall contributors. Smoking is a major contributor, and people who smoke 20 to 40 cigarettes a day can increase their overall cadmium exposure by 15 to 30%.

Levels of cadmium in the muscle meat of crab legs and claws – commonly called white crabmeat – are low. However, levels of cadmium in the brown meat from crabs can often be higher because crabs can accumulate cadmium from their diet in their digestive organ (the hepatopancreas) which is a component of the brown meat.

Examples of foodstuffs containing the highest cadmium (mg/kg)

Brown meat from crabs 3.90

Algal formulations 1.52

Seaweeds 1.12

Oilseeds 0.37

Horsemeat 0.36

Wild fungi 0.34

Edible offal 0.32

Water molluscs 0.32

Frogs’ legs 0.21

Cocoa powder 0.18

Bitter and bittersweet chocolate 0.14

Cultivated fungi 0.14

Crustaceans 0.13