1. What are metals?
Metals are elements and occur naturally in the earth’s crust. Metals are released naturally into the environment through, for example, volcanic eruptions or crustal erosion. Metal emissions are also caused by human activities, such as mining, industrial emissions, the use of fossil fuels and the incineration of waste. Today, anthropogenic emissions are very tightly regulated and controlled by environmental legislation. The main metals with regard to food safety include mercury, lead, cadmium and arsenic. At sufficiently high concentrations, metals have adverse effects on human health.
2. How is a person exposed to metals?
Because metals are naturally occurring elements, they are found in a wide variety of products and preparations. Exposure to metals can be occur, for example, through food or domestic water, but also through, for example, tobacco smoke or environmental pollution. However, the (heavy) metal content of food, domestic water, feed, fertilisers and consumer goods is strictly regulated and regularly monitored.
3. Why do foods contain metals?
Arsenic and cadmium occur naturally in the soil from which they may accumulate in plants. In addition, cadmium may be present in fertiliser products from which it may accumulate in crops. There can be big differences between plant species and even different varieties in the way they accumulate (heavy) metals occurring in the soil.
Lead occurs naturally in the air, soil and water, but also as an environmental toxin in areas of shooting ranges or metal smelters, for example. Mercury also occurs naturally in the environment, but it is also formed, for example, as a result of the use of fossil fuels. When animals eat (heavy) metal-containing food, metals also accumulate in foods of animal origin. This means that (heavy) metals are often found naturally or as a result of human activity in the raw materials from which food is made. However, legislation sets maximum levels for metal in food and feed in order to keep human exposure at a safe level.
Metals may also migrate to food from food contact materials and articles such as packaging materials, kitchen utensils and equipment, and tableware
4. What are the health effects of metals?
Metals affect many organs and body functions. Metals can inhibit or impair the action of various enzymes or impair the repair mechanisms of cell genetic material or DNA. At the tissue level, metals can adversely affect the kidneys and central nervous system in particular. The International Agency for Research on Cancer (IARC) has classified cadmium and arsenic as human carcinogens, lead as a likely human carcinogen and (methyl)mercury as a potential human carcinogen.
5. Do metals accumulate in the body?
Some of the metals are eliminated from the body, but in most cases very slowly. Cadmium and lead can linger in the body for up to decades, so metals can accumulate in the body as a result of exposure.
6. Are there especially many metals in Finnish food?
No. In general, there are low levels of metals in both domestic and foreign foods. The metal content of Finnish foods in some products may be higher than for imported foods (e.g. mercury in certain wild predatory fish), but in some foods the situation is the opposite (e.g. cadmium in cereals and cereal products). All EU member states comply with harmonised legislation, which also sets maximum levels for the content of metals in many different foods.
7. Are some foods particularly high sources of metal intake?
Even if a single food does not contain high levels of metals, it can be a significant source of metal intake due to abundant or general use. The intake of all harmful substances is affected not only by the concentration of the compound in the food, but also by the amount of that food in the diet. Different metals may occur in higher concentrations than usual in certain types of foods, such as mercury in some wild predatory fish or arsenic in rice. The internal organs of animals (liver and kidneys) usually contain more heavy metals than the meat. If foods are used in accordance with general dietary recommendations - and, where appropriate, guidelines for the safe use of foods - elevated metal levels in individual foods will not be harmful to health.
8. Are there a lot of heavy metals in industrial foods for young children?
No. Contaminant legislation sets the strictest maximum levels for metals specifically for industrial foods for young children. It should be noted that the legislation on foods for children only applies to industrial foods for young children - raw materials for home-made foods for children are generally subject to food law.
The results of the control project carried out by Evira and the municipal food control authorities in 2014, showed the levels of metals and other contaminants in industrial baby foods on the market in Finland to be very low.
9. Can an adult get too many heavy metals from their diet?
The exceptionally abundant, prolonged and one-sided use of some metal-rich foods may also lead to safe reference intakes being exceeded in adults as well. This means attention should also be paid to a balanced, varied and moderate diet for adults. Because of mercury in fish, Finnish Food Authority has issued instructions for the safe use of fish as an exception to the general recommendations for eating fish. In addition, the Finnish Food Authority has issued instructions for the safe use of oilseeds.
10. Can the intake of metals be completely avoided?
Because metals are naturally occurring compounds, their intake from food cannot be completely avoided. However, legislation sets maximum levels for metal in foods and feeds in order to keep human exposure at a safe level. In addition, the intake of metals and other contaminants can be reduced by eating an appropriate sufficiently balanced, varied and moderate diet.
11. What does it mean if the toxicological reference value for metal intake is exceeded?
Various toxicological reference values for metals have been established on the basis of observations from laboratory animal studies or population studies to describe the toxicity of the substance. A maximum tolerable weekly intake (TWI) has been set for cadmium and mercury. This is the dose that a consumer can consume every week throughout their life without harming their health. The latest studies show that there is certainly no safe dose for lead and arsenic. Lead and cadmium have been assigned what is known as a benchmark dose level (BMDL). This corresponds to the dose that causes an increased risk of an adverse reaction from the baseline of the population in a pre-agreed amount and reported as a subscript. This means that BMDL01 is a dose that, at the population level, increases the risk of myocardial infarction, for example, by a percentage higher than in the part of the population at which this exposure is lower.
Occasionally exceeding a toxicological reference value (e.g. TWI or BMDL) does not in itself constitute a health risk, as the values have been determined based prolonged exposure and take into account different safety factors to cover differences in sensitivity between animal species and individuals. Adverse effects usually occur in cases where the exposure is prolonged and continuous - for example, over several decades. However, a balanced, varied and moderate diet prevents repeatedly exceeding the toxicological reference value and further reduces the potential for adverse health effects.
12. Do organic products contain fewer metals than products made by traditional production methods?
Since metal levels are affected by a number of factors other than the method of cultivation, the metal content of organic products is not necessarily lower than that of similar products made by traditional production methods. Organic production has led to a reduction in cadmium levels in cereals, but no significant differences have been observed in other food groups. In the case of cereals, too, the situation is ambiguous, as some studies have shown even higher cadmium levels in organic cereals than in traditionally cultivated cereals.
13. Does cooking food affect metal levels?
No cooking method affects all metals in the same way in all foods. In fish, cooking may increase the metal levels in the food, while in meat the effect may be the opposite. Indeed, the effect of cooking on metal levels appears to depend on how much water is removed from the food during cooking.
14. Why are products containing harmful substances such as metals not banned?
Metals cannot be completely eradicated from food because they occur naturally in, for example, the soil, from which they are absorbed by plants. However, legislation sets maximum levels for metal in foods and feeds in order to keep human exposure at a safe level.
15. Do companies regularly monitor in their in-house control the metal levels in their products?
Yes. Operators' in-house control includes monitoring the composition of products also for potential contaminants such as metals. Food business operators are responsible for ensuring the safety of the product they have manufactured, had manufactured or imported and that the product otherwise complies with the legislation. Municipal food control authorities ensure that companies meet this obligation.
16. What is meant by a balanced, varied and moderate diet?
Balanced diet means choosing different foods from different food categories. Food categories include, for example, vegetables, fruits and berries, meat, cereals and cereal products, etc. A varied diet, on the other hand, means the use of different products from different categories (for example, different types of fruit and berries). Moderation in the size of portions is also a safety-enhancing principle. It is a good idea to scale food portions to match the age of the child and the usual doses for adults. A good diet includes a wide variety of foods and varies depending on the season, for example. A balanced, varied and moderate diet ensures an adequate intake of essential nutrients and on the other hand supports food safety.
17. Based on Finnish Food Authority's risk assessment, should certain foods be avoided in young children’s diet?
Finnish Food Authority has issued recommendations to restrict the consumption of certain foods by young children due to the metals they contain. These include exceptions to general fish eating recommendations for certain fish and the recommendation that rice beverages should not be used as the only beverage for young children. Also instructions should be complied with for the safe consumption of oilseeds.
Based on the risk assessment , these recommendations on restrictions on the use of food are necessary to reduce young children's exposure to (heavy) metals and should therefore remain in force. On the other hand, the study shows no need for new recommendations to limit the use of individual foods. It is important to remember the importance of a balanced, varied and moderate diet.
18. Do metals pose a problem for persons on a special diet?
For persons on a special diet, a very one-sided diet can constitute a significant source of metals. This is why in special diets, such as a gluten-free diet, it is a good idea to make sure that substitute products are used as widely as possible instead of foods that are avoided. For example, besides rice, millet, buckwheat, corn, gluten-free oats can be consumed, as well as a variety of potatoes, root vegetables, rice and other suitable cereal supplements.