Which Foods are Contaminated with Heavy Metals?

Which fish or meat products? Do you not recommend foods for children or adults because of their heavy metal content (lead, cadmium, mercury)? I am thinking specifically of canned tuna and saltwater fish and aquaculture.

About 55% of the total mercury  comes from animal foods and 45% from plant foods. The particularly problematic methylmercury (organic mercury) is mainly ingested from fish and seafood.

In all other foods, mercury is mostly in inorganic form, which is less dangerous to human health.

Fish with potentially higher levels of pollution include shark, butter mackerel, eel, loach, swordfish, halibut, pike, monkfish, tuna and also redfish. The level of mercury accumulation in fish depends on their position in the food chain, to a lesser extent on the area where they were caught, but especially on their age. Large, old predatory fish in particular, which are at the end of the food chain, can have increased levels of mercury due to years of accumulation. These include large specimens of swordfish, shark, marlin, marlin and large tuna.

On the other hand, rather fast-growing fish species that are further down the food chain, such as plaice, cod, herring and pollock or hake, are usually only slightly contaminated. However, due to their comparatively frequent consumption, these fish can still make a major contribution to mercury intake, even if they are only slightly contaminated.

Canned tuna sold in Germany is primarily made from younger fish. However, test results show that individual samples still contain mercury levels that come close to the permissible maximum levels.

Fish from aquaculture are generally harmless.

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

To reduce mercury intake it is recommended:

• Wash and/or peel fruit and vegetables thoroughly, as dust containing heavy metals can accumulate on the surface of fruit and vegetables.
• Consume no more than 250 g of wild mushrooms (based on the fresh weight) per week (unlike green plants, mushrooms have the ability to accumulate heavy metals).
• Rarely eat offal, especially from wild animals.
• Women who want to have children, pregnant women, breastfeeding women and small children should rarely consume the fish species at the end of the food chain and prefer less contaminated fish species. These are usually e.g. Alaskan wild salmon, mackerel, herring or pollock and fish from farmed ponds, e.g. trout and carp.

Cadmium  is present in both plant and animal foods due to its wide occurrence in soil. Therefore, the intake of the heavy metal cannot be completely avoided. A varied selection of foods is recommended. Then, more heavily contaminated foods are automatically alternated with less contaminated foods. In addition, a good supply of nutrients is more likely to be guaranteed.

Very high levels of cadmium are often found in offal, seafood, algae (be careful with dietary supplements ), oilseeds (such as poppies, sunflower seeds, flaxseed, sesame), certain types of mushrooms and dark chocolate.

The main contributors to the overall exposure, however, are the products consumed in large quantities with only a low or average cadmium content. 90 percent of the cadmium that every adult absorbs on average comes from plant food. Despite lower cadmium levels, grain and grain products (26 percent), vegetables and vegetable products (16 percent) and starchy roots and tubers (16 percent) provide the majority.

The health benefits of a plant-based diet outweigh the potential disadvantages. So if you eat a lot of vegetables and grains, you should not change your eating habits.

Tips for a low-cadmium diet:

• Eat a varied diet.
• No more than 200 to 250g of wild mushrooms per week.
• Eat offal (especially from wild animals) only occasionally.
• Oil seeds (linseed, sunflower seeds) maximum 20 grams per day.
• Enjoy chocolate with a high cocoa content in moderation.

Lead

Gasoline has long been the primary source of lead pollution. With the introduction of unleaded petrol, it has decreased significantly. The heavy metal is released into the air through industrial exhaust fumes and can be deposited on plant foods as lead-containing dust.

Shellfish and shellfish products in particular are more heavily contaminated with lead. Even here, however, the limit values ​​are rarely reached or exceeded.