Food Additives & Contaminants: Part A. 2016; 33:1, 41-53.
Quantitative risk assessment on the dietary exposure of Finnish children and adults to nitrite
Johanna Suomi1, Jukka Ranta1, Pirkko Tuominen1, Tiina Putkonen2, Christina Bäckman2, Marja-Leena Ovaskainen3, Suvi M. Virtanen3,4,5 & Kirsti Savela1
1 Risk Assessment Research Unit, Finnish Food Safety Authority Evira, Helsinki, Finland
2 Chemistry and Toxicology Unit, Finnish Food Safety Authority Evira, Helsinki, Finland
3 Unit of Nutrition, National Institute for Health and Welfare THL, Helsinki, Finland
4 School of Health Sciences, University of Tampere, Tampere, Finland
5 Research Center for Child Health, Tampere University and University Hospital, and the Science Center of Pirkanmaa Hospital District, Tampere, Finland
Nitrite intake from the consumption of cured meat and tap water was estimated for Finnish children of 1, 3 and 6 years as well as Finnish adults of 25–74 years. Nitrite content in the foods was measured by capillary electrophoresis, and was then used together with individual food consumption data from the FINDIET 2007 and DIPP studies in a stochastic exposure assessment by a Monte Carlo Risk Assessment (MCRA) program. Nitrite intake from additive sources and tap water was assessed, and more than every 10th child between the ages 3 and 6 years was estimated to have a nitrite intake exceeding the acceptable daily intake (ADI) of nitrite. The high exposure levels were caused by frequent consumption of large portions of sausages, up to 350 g day–1 or 750 g in 3 days, among the children. Median nitrite intake from cured meat was 0.016, 0.040, 0.033 and 0.005 mg kg–1 body weight day–1 for children of 1, 3 and 6 years and adults, respectively. Bayesian estimation was employed to determine safe consumption levels of sausages and cold cuts for children, and these results gave rise to new national food consumption advice.
Nitrite (nitrite ion NO2–) is used as food preservative to prevent the growth of dangerous microbes, particularly Clostridium botulinum. The use of nitrites (E249 or E250) is necessary especially if the product has low salt content, if there are doubts about the efficiency of the cold chain management or if the storage time is long. However, high intake of nitrite is linked to a number of health effects, e.g. methaemoglobinemia. Therefore, maximum added amounts of nitrite in foods are defined in legislation ((EC) No 1333/2008). In Finland, the usual added amounts in processed meat have typically been 80 to 120 mg kg-1, which is lower than the legislative maximum amounts.
Our aim was to find out the levels of dietary nitrite exposure among Finnish consumers of different ages and to assess whether the exposure of any population subgroup exceeds the level which does not cause any damage to health (the acceptable daily intake ADI).
The ADI of nitrite is 0.07 mg nitrite ion kg-1 consumer’s body weight day-1. It was determined on the basis of toxicological effects on the heart and the lungs in a 2-year rat study [ref 1], and the most recent EFSA expert opinion [ref 2] agrees that the available data gave no reason to change the value.
The main source of total nitrite in the body is endogenous formation of nitrite from nitrate consumed in e.g. leafy vegetables. However, most studies show health damaging effects only in connection to nitrite consumed in nitrite form, such as nitrite additives to cured meat.
In our study [ref 3], the nitrite exposure of Finnish children of 1 to 6 years and adults of 25 to 74 years was evaluated using individual consumption data of foods containing nitrite as additive and analysis results of those foods. A new capillary electrophoresis method was also developed and validated for the measurement of nitrite and nitrate from foodstuffs. Based on the consumption data collected previously and the concentration data measured in this study, the exposure of the different age groups was calculated probabilistically using a Monte Carlo based online program.
Among the adults and elderly people, the nitrite intake of men was higher than that of women, and the highest exposure (relative to the individual’s body weight) was found among men of 35 to 40 years. The middle-aged Finnish men consumed the nitrite containing foods the most, particularly different sausages. Despite the high consumption we found out that only a tiny part (0.05%) of the studied adult population was in danger of exceeding the ADI of nitrite.
Among the children, the 1-year-olds consumed nitrite-containing foods in moderation, but roughly one in ten children in the 3-year-old and 6-year-old age groups had nitrite exposure exceeding the ADI of nitrite. Different types of sausages were the main source of added nitrite for the children, and some of the children in the studied population consumed high amounts of sausages (up to 750 g in three days). Figure 1 shows the sources of nitrite exposure for 3-year-old Finnish children. The sources shown only include foods where nitrite is used as food additive. Nitrite formed endogenously from consumed nitrate is not shown in the figure.
From the results it was evident that the children in the studied group ate nitrite-containing foods too much and too often. It was therefore necessary to assess a safe portion size for the children so that consumption advice could be given.
Using Bayesian statistics, a “safe” weekly portion size of sausages, cold cuts or a combination of both foods was calculated. The portion size was determined so that the exposure from these foods and from a fixed value of exposure from drinking water remains below or equal to the ADI. Average body weights of children in each age group were used in the calculations, and the distribution of nitrite levels of the sausages and cold cuts were based on concentrations measured from these products. Since nitrite levels in meat products decrease over time, the foods were measured a week before their best-before dates, which was estimated to be the most probable time of consumption.
This risk assessment provided valuable information for choosing risk management actions to improve the health of consumers. Based on the results of this study as well as on the fat and salt levels of sausages sold in Finland, new consumption advice [ref 4] were given for Finnish children.
 WHO Food Additives Series. First draft by Speijers GJA & van den Brandt PA. (2003) Nitrite (and potential endogenous formation of N-nitroso compounds. In: WHO Food Additives Series No. 50, Safety evaluation of certain food additives. WHO.
 EFSA, Panel on Food Additives and Nutrient Sources added to Food (ANS) (2010). Statement on nitrites in meat products. EFSA Journal 8(5):1538-1550.
 Suomi J, Ranta J, Tuominen P, Putkonen T, Bäckman C, Ovaskainen M-L, Virtanen SM, Savela K. (2016) Quantitative risk assessment on the dietary exposure of Finnish children and adults to nitrite. Food Additives & Contaminants: Part A. 33:1, 41-53. DOI: 10.1080/19440049.2015.1117145
Assoc.Prof, Ph.D., Senior Researcher
Finnish Food Safety Authority Evira
Mustialankatu 3, FI-00790 Helsinki, Finland