Eating habits affect the intake of heavy metals

The national risk assessment by the Finnish Food Authority specifies the estimated amounts of exposure of consumers that were previously published by the European Food Safety Authority (EFSA) at the EU level. Based on the results, a part of working-age Finnish adults are exposed to amounts of heavy metals in food that exceed the level of insignificant risk. The likelihood of organ damage is nevertheless low. In the risk assessment by the Finnish Food Authority, the exposure of Finns of 25 - 74 years of age to cadmium, lead, inorganic arsenic, different forms of mercury, nickel and aluminium in food and drinking water was studied. The exposure to heavy metals was the greatest in the youngest age groups, and it decreased by age.

The largest sources of heavy metals for average consumers are usually the food categories that are consumed often and in large doses, such as bread, different kinds of beverages as well as coffee, fish and shellfish.

“For the part of the population with the most exposure, products with higher concentrations of heavy metals than in food on average are also large sources of exposure. For example, oil seeds such as sunflower seeds may be a significant source of cadmium and nickel for consumers who consume a lot of them, and the concentrations of different heavy metals in food supplements may be considerable”, says Senior Researcher and Docent Johanna Suomi, PhD, Risk Assessment Unit of the Finnish Food Authority.

Young women are exposed to heavy metals

“Finnish women of 25 - 45 years of age get more heavy metals from their food than women who have passed the fertile age. Because heavy metals can be transferred to the foetus through the placenta, exposure during and partially before pregnancy may affect the development of the future child. Many of these harmful substances damage the developing central nervous system, among other things”, Suomi says.

Exposure to methylmercury, found in fish and other seafood, was an exception. Its intake was the highest for those over 65 years of age, because according to the FinDiet 2007 and 2012 data, they ate more fish more often than younger Finns.

The exposure to mercury was low for the majority of the population, however: the tolerable weekly intake of methylmercury was exceeded by roughly 1.5 % of 25 - 64 -year-olds and a bit over 3 % of 65 - 74 -year-olds. For everyone studied, the intake of inorganic mercury was clearly under the maximum tolerable weekly intake, which means that the risk is insignificant.

Heavy metals damage bones and internal organs

Exposure to cadmium has been linked to the increased risk of osteoporosis in postmenopausal women. In the risk assessment, it was found that based on the food consumption information from 2012, approximately one fifth of the women over 45 years old receive amounts of cadmium in their diet that have been linked to an elevated risk of osteoporotic fractures. For approximately 6 %, the risk is more than three times higher than the risk for those with less exposure.

For a bit less than one per cent of the Finnish adult population, cadmium exposure exceeds the maximum tolerable weekly intake defined by EFSA. Exceeding the maximum value may lead to kidney damage.

For some Finns, the nickel exposure through food is so high that people with a nickel allergy may also get skin symptoms due to food-based exposure.

Aluminium, which is found in food as a contaminant, remains under the maximum tolerable weekly intake for all groups studied; the maximum value is based on the amount that causes damage to the central nervous system in animal tests and a safety factor.

Not all heavy metals have a prescribed safe amount of exposure

Out of the heavy metals studied, inorganic arsenic and lead do not have an amount of exposure that is considered safe. In fact, they are linked to a low or moderate risk of health hazards for a part of the population.

The concentration of arsenic in well water can be high in certain parts of Finland, and those who drink such water may be exposed to significantly higher amounts of arsenic than estimated in the risk assessment based on the concentration in drinking water.

The exposure of Finns to lead is low, however, and lead concentrations in food have decreased during the last few decades.

The exposure estimate was made based on the food consumption information gathered in the FinDiet studies in 2007 and 2012 as well as the monitoring data of the authorities, previous research projects, and the concentration database compiled based on the own-check results of the industry.

By following the instructions for safe use on the website of the Finnish Food Authority, consumers can reduce their exposure to heavy metals. 

Risk assessment on the dietary heavy metal exposure and aluminium exposure of Finnish adults (pdf) in Finnish, the description in English.

Instructions for safe use of foodstuffs 

Further information:

Senior Researcher Johanna Suomi, Risk Assessment Unit, johanna.suomi@ruokavirasto.fi