The Finnish Food Authority (Ruokavirasto) studied the exposure of working-age and elderly people to cadmium, lead, arsenic, mercury, nickel and aluminum via food and drinking water.
The magnitude of lead and inorganic arsenic intake was such that health hazards could not be ruled out, but their probability is low or at most moderate. Non-alcoholic drinks including rice-based drinks, cereals (including rice) as well as fish and seafood were the top sources for inorganic arsenic exposure.
Lead concentrations in food have also decreased during the past few decades, according to the report. Cereals, vegetables, fruit and berries and non-alcoholic drinks are the main sources. These groups are also the main foods for aluminum as a contaminant.
Food eaten a lot and in big quantities
The main sources of heavy metals for average consumers are food categories that are consumed often and in large doses, such as bread, different beverages including coffee, fish and shellfish.
“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,” said Johanna Suomi, senior researcher in the Risk Assessment Unit of the Finnish Food Authority.
Exposure estimates were made based on food consumption information from the FinDiet studies in 2007 and 2012 as well as monitoring data of the authorities, previous research projects, and the concentration database compiled based on own-check results from industry.
One in five women over the age of 45 have an elevated risk of osteoporotic fracture due to cadmium exposure. For 6 percent the risk is more than three times higher than for those with less exposure. The greatest dietary exposure to heavy metals was faced by women of fertile age (from 25 to 45 years old) but the mercury exposure of this group was low.
“Finnish women of 25 to 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 fetus 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,” said Suomi.
Heavy metal exposure except methylmercury drops with age
Exposure to methylmercury, found in fish and other seafood, was highest for those over 65 years old, because according to FinDiet 2007 and 2012 data, they ate more fish more often than younger people.
The exposure to mercury was low for most of the population, however the tolerable weekly intake of methylmercury was exceeded by roughly 1.5 percent of 25 to 64-year-olds and 3 percent of 65 to 74-year-olds. For everyone studied, the intake of inorganic mercury was under the maximum tolerable weekly intake, which means the risk is insignificant.
For less than one per cent of the Finnish adult population, cadmium exposure exceeds the maximum tolerable weekly intake defined by the European Food Safety Authority (EFSA). Exceeding this maximum value may lead to kidney damage.
Cadmium exposure comes mainly from plant-based foods like cereals, vegetables and potatoes, since they are consumed often but concentrations are mostly not high.
For some people, the nickel exposure through food is so high that those with a nickel allergy may also get skin symptoms due to food-based exposure.
Aluminum, which is found in food as a contaminant, remains under the maximum tolerable weekly intake for all groups studied.