Risk of colorectal and other gastro‐intestinal cancers after exposure to nitrate, nitrite and N‐nitroso compounds: a follow‐up study

Abstract

N-nitroso compounds are potent carcinogens detected in foodstuffs. The importance of dietary nitrosamines in relation to human cancer development is, however, uncertain. We studied the relationship between intake of nitrates, nitrites and N-nitrosodimethylamine (NDMA) and risk of cancers of the gastro-intestinal tract in a cohort of 9,985 adult Finnish men and women. During a follow-up period of up to 24 years, 189 gastro-intestinal cancer cases were diagnosed in the cohort, initially free from cancer. Intake of nitrate, nitrite and NDMA were estimated, based on food-consumption data from a 1-year dietary history interview covering the total diet of the participants. A significant positive association was observed between intake of NDMA and subsequent occurrence of colorectal cancer with a relative risk (RR) between the highest and lowest quartiles of intake of 2.12 [95% confidence interval ( N-nitroso compounds are potent carcinogens that can induce tumours in various animal species at a variety of sites (Forman, 1987;Tricker and Preussmann, 1991). Humans are exposed to nitrosamine compounds both from the diet and other environmental sources as well as from endogenous synthesis within the body (Mirvish, 1995;Bartsch and Spiegelhalder, 1996). N-nitrosodimethylamine (NDMA) and other volatile N-nitroso compounds have been detected in foods with added nitrates or nitrites, such as salt-preserved fish and meat, and in food processed by smoking or direct-fire drying (Scanlan, 1983;Hotchkiss, 1989).It is plausible to hypothesize that N-nitroso compounds from foods represent a risk factor for cancers of the gastro-intestinal tract. This is supported by results from both ecological comparisons and case-control studies that have shown an increased risk of cancers of the stomach and upper aerodigestive tract associated with intake of foods with potentially high contents of nitrosamines, such as salted, smoked and pickled foods (Kono and Hirohata, 1996;Eichholzer and Gutzwiller, 1998). Increased risk of colorectal cancer has been associated with high consumption of processed meats in several cohort studies (Bjelke, 1980;Willett et al., 1990;Giovannucci et al., 1994;Goldbohm et al., 1994). A few studies on the intake of NDMA and occurrence of cancers of the stomach and upper aerodigestive tract have yielded discrepant findings (Risch et al., 1985;Chyou et al., 1990; Gonzáles et al., 1994;La Vecchia et al., 1995;Pobel et al., 1995;Rogers et al., 1995). We investigated whether intake of NDMA or foods rich in nitrosamines is predictive for colorectal cancer or other cancers of the gastro-intestinal tract in a Finnish cohort of men and women followed up for up to 24 years. POPULATION AND METHODSDuring the period 1966-1972, the Mobile Health Clinic of the Social Insurance Institution undertook multiphasic screening examinations in several regions of Finland (Knekt, 1988). As part of the main study, detailed data about food consumption were collected from 9,985 individuals who had never had cancer, by dietary history interview (J...

Dietary intake of different types and characteristics of processed meat which might be associated with cancer risk – results from the 24-hour diet recalls in the European Prospective Investigation into Cancer and Nutrition (EPIC)

“…This raises the question whether information at the food level as an indicator of cured PM consumption is sufficient to describe exposure differences for nitrite/nitrate through PM consumption, because this approach assumes a similar NaNO 2 content in the ready-to-eat PM products in the different countries which might not be correct. In a Finnish study, conducted between 1966 and 1972, mean intake of nitrite was 5.3 mg day 21 , provided nearly exclusively by cured meats and PM 5,36 . However, another report from Finland calculated an average daily intake of 1.88 mg 33 .…”

Processed meat consumption, dietary nitrosamines and stomach cancer risk in a cohort of Swedish women

“…However, that conclusion was based mainly on casecontrol studies, which are more susceptible to systematic bias than prospective cohort studies, and recent prospective studies have been inconsistent. [3][4][5][6] Besides much salt and nitrites or nitrates, processed meat products like bacon, sausage and ham often contains carcinogenic nitrosamines.7-9 N-nitrosodimethylamine (NDMA) is the most frequently occurring nitrosamine in foods.10 Nitrosamines can also be formed endogenously in the stomach through nitrosation of nitrite with amines.7 To date, 5 case-control studies [11][12][13][14][15] and only 1 prospective cohort study 3 with a small number of cases (n 5 68) have investigated the association between NDMA or nitrosamine intake and stomach cancer risk, with 4 case-control studies [11][12][13]15 showing a positive association.To examine whether associations exist between intake of processed meat and NDMA and risk of stomach cancer, we used prospective data from the Swedish Mammography Cohort, a large population-based cohort with 18 years of follow-up and repeated assessments of diet. In addition, we evaluated risk of stomach cancer in relation to consumption of red meat, poultry and fish.…”

Food Additives in Products for Children Marketed in Brazil

“…Several studies indicate adverse effects to food additives, in both acute and chronic forms, such as toxic reactions in metabolism, triggering allerg ies [4][5], carcinogenicity in animals [6], p robable carcinogenicity in hu mans [7][8] and behavioural changes [9][10]. Regarding such effects, those that are linked to children health stand out, because children are among the biggest consumers of p rocessed products and, thus, have more susceptibility to these adverse effects.…”