Total mercury is absorbed about 55% from animal and 45% from plant foods. The particularly problematic methylmercury (organic mercury) is mainly absorbed from fish and seafood.

In all other foods, mercury is predominantly present in inorganic form, which is less dangerous for human health.

Potentially more contaminated fish include shark, butterfish, eel, wolffish, swordfish, halibut, pike, monkfish, and tuna. In contrast, plaice, herring, and pollack are generally low in contamination. Especially these fish, which are consumed in large quantities, can contribute significantly to mercury intake even if they are low in contamination.

According to the Max Rubner Institute (MRI), the mercury content of most fish marketed in Germany is below the maximum levels, especially from fish from the North Atlantic. Exceptions are large and old specimens of tuna, white halibut, or swordfish. Such fish are rare and are examined before they may be traded.

Tuna offered in cans in Germany is primarily made from younger fish. However, test results show that some samples still have mercury levels approaching the permissible maximum levels.

In general, old fish are significantly more contaminated with methylmercury than young ones. Predatory fish (e.g., tuna) are also more contaminated than non-predatory fish (e.g., sardines, breams).

Fish from aquaculture is generally safe.

To reduce mercury intake, it is recommended:

• Wash and/or peel fruits and vegetables thoroughly because heavy metal-containing dust can settle on the surface of fruits and vegetables.
• Consume no more than 250g of wild mushrooms (based on fresh weight) per week (unlike green plants, mushrooms can accumulate heavy metals).
• Eat offal, especially from wild animals, rarely.
• Women planning to become pregnant, pregnant women, breastfeeding mothers, and young children should rarely consume fish species at the end of the food chain and prefer less contaminated fish species. These usually include, for example, Alaska wild salmon, mackerel, herring, or pollack, as well as fish from fish farms, such as trout and carp.

Cadmium is present in both plant and animal foods due to its wide occurrence in soils. Therefore, it is impossible to completely avoid the intake of this heavy metal. A varied selection of foods is recommended. This automatically alternates between more and less contaminated foods, and a good supply of nutrients is more likely to be ensured.

Very high cadmium levels are often measured in offal, seafood, seaweed (caution with dietary supplements), oilseeds (such as poppy seeds, sunflower seeds, flaxseeds, sesame), certain types of mushrooms, and dark chocolate.

The total exposure is mainly contributed by products consumed in larger quantities with only low or average cadmium content, such as vegetables and grain products.

The health benefits of a plant-based diet outweigh the potential disadvantages. Therefore, those who consume a lot of vegetables and grains should not change their eating habits.

For a long time, gasoline was the main cause of environmental lead pollution. The introduction of lead-free gasoline has significantly reduced it. Industrial emissions release heavy metals into the air, which can settle as lead-containing dust on plant foods.

More heavily contaminated with lead are mainly shellfish and shellfish products. However, the limits are rarely reached or exceeded here as well.